PART II – ELECTRICAL SAFE WORK PRACTICES

1 Electrical Safety Principles & Controls

1.1 Principles of Electrical Safety

1.1.1 Electricity is different from other forms of hazardous energy, because it is both
undetectable by human senses and potentially immediately fatal upon contact.
Since we use electricity every day and everywhere in our lives, this requires a
broad application of specialized equipment construction methods and safe work
practices to prevent serious injuries or death.

1.1.2 All electrical equipment must be installed and used in accordance with
manufacturer’s instructions. Equipment shall be approved for use (accepted by
the Electrical AHJ) and shall not be modified or used outside of its approval
intent. See the Electrical Equipment Safety Program for more information.

1.1.3 Sufficient training is required to safely interact with electrical equipment.

Operators must be trained to operate equipment within its design intent and to not
defeat engineering controls.

1.1.4 Personnel who service, modify, repair or build electrical equipment must be
able to recognize the hazards and establish controls to prevent injury. These
personnel are called Qualified Electrical Workers (QEW’s).

1.1.5 The most fundamental aspect of QEW training is the ability to Test Before
Touch. Without an innate human sense to detect a hazardous condition, QEW’s
must understand how to properly use test equipment to prove an Electrically
Safe Work Condition.

1.1.6 Live repair work is considered extremely hazardous and is generally

prohibited. Exceptions can be made but require detailed justification and
approval by senior management (EEWP – Section 6.6).

1.1.7 Whenever possible, all work performed on equipment will be performed

deenergized. In order to prove and maintain deenergization, QEW’s must follow
a strict process to establish an Electrically Safe Work Condition. This process
involves both Lockout/Tagout and Test Before Touch. Because this is so
fundamental to safe electrical work, it is captured in the electrical safety
medallion in Fig. 4.1.7.
1.1.8 Some forms of diagnostics require the equipment to be energized while circuit
parts are exposed. Only QEW’s with the proper PPE may perform diagnostics.

1.1.9 Some combinations of switching, testing and LOTO can involve significant
procedural complexity. In these cases, written work plans are developed,
reviewed and approved by knowledgeable parties in advance and executed with
formal procedural compliance. Refer to 6.8 for how and when to build an
Electrical Safe Work Procedure.

1.1.10 Proper body positioning must be an integral part of both everyday work habits
and detailed work planning. This principle is embedded in the shock protection
and arc flash protection boundaries, but must also be emphasized in everything
from routine switching activities to setting up barriers and barricades.

1.2 Application of ISM to Electrical Safety

1.2.1 The Integrated Safety Management process applies in full to electrical work.

1.2.2 The general process for implementing ISM can be found in PUB-3140,
Integrated ES&H Management Plan.

1.2.3 Every electrical job requires an appropriate level of electrical hazard analysis,
work planning, authorization and direct field supervision (6.11) that is
commensurate with the risk level of the job.
1.2.4 ISM Steps for Electrical Work:

a. Step 1: Define the scope of work

b. Step 2: Analyze the hazards

c. Step 3: Develop/implement controls

d. Step 4: Perform work

e. Step 5: Feedback and improve

1.3 Planning Electrical Work

1.3.1 Every electrical job shall be planned in advance of performing the job briefing.

1.3.2 Planning can be formal or informal, depending on the level of risk and the
determination of the risk assessment.

1.3.3 Planning is simply performing the first three steps in the ISM process loop in 4.2.4:

a. Define the scope of work

b. Analyze the Hazards

c. Develop/Implement controls
1.3.4 Certain higher risk jobs require the plan to be formally documented in an
Electrical Safe Work Procedure (ESWP). See 6.8.

1.3.5 Electrical Hazard Analysis

a. If the energized electrical conductors or circuit parts operating above the shock
hazard thresholds of
2.2.13 are not placed in an Electrically Safe Work Condition, other safety-
related work practices, such as the ones described in Sections 6 through 10,
shall be used to protect employees who might be exposed to the electrical
hazards involved.

b. Such work practices shall protect each employee from arc flash and from
contact with energized electrical conductors or circuit parts, operating above
the shock hazard thresholds of 2.2.13, directly with any part of the body or
indirectly through some other conductive object.

c. Work practices that are used shall be suitable for the conditions under
which the work is to be performed and for the voltage level of the
energized electrical conductors or circuit parts.

d. Appropriate safety-related work practices shall be determined before any

person is exposed to the electrical hazards involved by using both shock
hazard analysis and arc flash hazard analysis.
 A shock hazard analysis shall be performed in accordance with 7.1.
 An arc flash hazard analysis shall be performed in accordance with 8.1.

e. The electrical hazard analysis determines the type and rating of shock and arc
flash PPE, as well as approach boundaries to be used.

1.3.6 Developing Controls

a. Depending on the results of the Electrical Hazard Analysis, controls must be

selected to minimize both the risk to the persons performing the work and to
persons who may be in the area. Controls are selected from Section 6. The
following are examples of questions to consider when planning the work.

b. Determine who can perform the work.

 Who will be the Person In Charge?
  What level of QEW is required?
 Is a Standby Person or Safety Watch required?

c. Determine what level of documentation or authorization is required.

 Is a written ESWP required?
 Is an EETP or EEWP required?
 Is a complex LOTO procedure required?
 d. Determine how to minimize exposure to the workers.
 Can the arc flash energy be reduced?
 Can parts of the system be locked out?
 Can additional temporary barriers be placed over exposed parts or openings?

e. Determine how to control access to the work area.

 Are barricades required?
 Should attendants be stationed to control access?

f. Determine what other additional controls should apply.

1.4 Hierarchy of controls

1.4.1 To prevent and mitigate hazards, controls must be tailored to the work being
performed, the risk of harm posed by the work, and the extent or degree of harm
that could occur while performing the work. This tailoring of controls to hazards
based upon risk is generally referred to as the “graded approach.”

1.4.2 The preferred hierarchy of controls is:

a. Elimination or substitution of the hazards: in the design of equipment or

apparatus, careful consideration should be made when applying hazardous
electrical power to a device. For example, control and interlock circuitry
could be designed to operate at 24 VDC instead of 120 VAC.

b. Engineering controls: in the design of equipment or apparatus, permanent

guarding, enclosing, or insulation of hazardous voltage sources to prevent
unnecessary exposure to the operator.

c. Administrative controls: implementation of an Electrically Safe Work

Condition (Lockout/Tagout), restricted access to qualified electrical workers,
and documented safe work plans are examples of administrative controls.

d. Personal protective equipment: working on energized equipment while

protected with PPE is a last resort.
1.4.3 The tailoring process should include:

a. Identifying controls for specific hazards

b. Establishing boundaries for safe operation

c. Implementing and maintaining controls

1.5 Authorization

1.5.1 Authorization to perform electrical work is covered by the ES&H Manual Work
Planning and Control
program. All electrical work shall require line management authorization.

1.5.2 Specific authorization is to be provided by the activity lead after the employee
has been approved as a Qualified Electrical Worker by the Electrical AHJ for
Safe Work Practices and has received equipment- specific training. The activity
lead must ensure that the employee is thoroughly familiar with the equipment
(within the context of his or her job function) and with the energy-control
procedures.

1.5.3 The authorizing person shall consider the following factors in authorizing electrical
work:

a. Who is performing the work? Are they suitably qualified and experienced?

b. Who is supervising the work? Are they suitably qualified and experienced?

c. Is a written Electrical Safe Work Procedure (ESWP) necessary or advised?

d. Are any permits required and have they been approved?

e. What system operational conditions will (or should) be required? Are these
accounted for in the plan?

f. What could go wrong and what should be done about it? Is the level of
planning and supervision appropriate for the level of risk?

1.6 Executing the Plan

1.6.1 Every electrical job shall have a designated Person In Charge (PIC) (6.9).

1.6.2 The PIC shall perform a Job Briefing with all persons involved prior to executing the
job (6.12).

1.6.3 Individual Qualified Electrical Workers should think through the set of self-
 control questions to ensure they are adequately prepared for the task (4.7).

1.6.4 The PIC should remain alert for changes in the scope of work that may
naturally develop during the execution of the plan. Individual QEW’s shall
notify the PIC for any change in the scope of work. A change in scope shall
trigger a review of the hazards and controls.

1.7 Self-Controls for the Qualified Electrical Worker

1.7.1 Electrical safety self-control is a process by which one performs his or her own
safety analysis before beginning any task. This is the first step of a personal
hazard/risk analysis. It can be accomplished by simply asking questions of
oneself. If one can honestly answer “yes” to all of the following questions, he or
she has done well at controlling his or her own safety. If one responds “no” to
any of the questions, there is a safety concern that he or she should address
before proceeding with the work.

1.7.2 This set of self-control questions makes the employee slow down and think
about what he or she is going to do. Applying these controls can significantly
reduce the probability of the employee being injured or killed while
performing electrical work.

a. Do I fully understand the scope of the work?

b. Am I trained and qualified to perform this work safely?

c. Have I performed this type of task before; if not, have I discussed the details with
my supervisor?

d. Have I thought about possible hazards associated with this work and taken
steps to protect myself against them?

e. Have I determined whether or not I will be near exposed energized parts?

f. If I am going to be exposed to energized parts, can they be put into an

Electrically Safe Work Condition? [If “No,” skip to item i.]

g. Did I verify, using appropriate protective and test equipment, that the
 conductors or equipment are in a de-energized state?

h. Have I applied a lockout/tagout device?

i. If I will be exposed to energized parts, do I know what voltage levels are involved?

j. Do I know the safe approach distance to protect against the electrical shock
hazard?

k. Do I know the safe approach distance to protect against the electrical arc/flash
hazard?

l. If a permit for energized work is required, have I obtained one?

m. Do I have the proper electrical PPE for this type of energized electrical work?

n. Do I have the appropriate voltage-rated tools and test equipment, in the

proper working order, to perform this work?

o. Have I considered and controlled the following factors in my work environment?

 Close working quarters
 High traffic areas
 Intrusion/distraction by others
 Flammable/explosive atmosphere
 Wet location
 Illumination in the area

p. Do I understand that doing the work safely is more important than the time
pressure to complete the work?

q. Do I feel that all of my safety concerns about performing this work have been
answered?
2 General Electrical Safety for All Persons

2.1 Scope

2.1.1 This section applies for all personnel at Berkeley Lab, both QEWs and non-QEWs.

2.1.2 This section deals primarily with workplace electrical safety. This includes
working around or with electrical equipment, but does not include working
on or inside electrical equipment.

2.2 General requirements

2.2.1 A fundamental principle of electrical safety is that only Qualified Electrical

Workers (QEWs) may be authorized to perform electrical work. This includes
both live and deenergized work, for build, service, maintenance, and repair of
equipment. A more detailed description of electrical work and what non- QEWs
may perform is in 6.3.

a. A QEW is one who has demonstrated skills and knowledge related to the
construction and operation of electrical equipment and installations, has
received safety training to identify and avoid the hazards involved, and who has
been approved by the Electrical AHJ for Safe Work Practices.

b. Any person who is not a QEW is called a non-QEW.

c. A non-QEW may perform deenergized electrical work under the direct field
supervision of a QEW.

2.2.2 Safe work practices for the non-QEW generally include the following:

a. Proper handling and use of cord- and plug- connected equipment.

b. Ensuring that electrical equipment is listed by an NRTL or inspected and

found acceptable by the Electrical AHJ for non-NRTL equipment. The
equipment must not be modified and must be used in accordance with its
listing intent. See the Electrical Equipment Safety Program.
 c. Reporting all instances of defective electrical equipment for repair by a Qualified
Electrical Worker.

d. Proper safe work practices for switching electrical disconnects and circuit breakers.

2.3 Recognizing electrical hazards

2.3.1 Deenergizing electrical equipment

a. Power switches: The normal operator method for turning off electrical
equipment typically does not remove all electric power from the equipment.
Some electrical parts within equipment still remain live even after all visible or
audible signs seem to show otherwise. Just because the external lights turn off,
vibration sounds cease, and visible movement stops, do not assume that there is
no shock
 hazard within electrical equipment. A shock hazard may still exist when
enclosure panels or covers are removed.

Fig. 5.3.1.a – This thermal evaporator was placed out of service because of a fluid leak.
Although the power switch was turned off and the control panel showed no visible sign of
electric power, the cord was still plugged in (behind the drawer cabinet to the left) and
the 220V transformer in the bottom (next to the red wires) had exposed live parts. The
cover panel, which was removed, did not have any shock hazard warning label. The
evaporator is not listed by an NRTL and had not been inspected under the Electrical
Equipment Safety Program. The evaporator should have been inspected, labeled, and
unplugged prior to removing the panel.

b. Emergency Stops (E-Stops) have various design parameters, but most are only
designed to immediately stop moving parts when a person gets caught in the
machinery. This does not remove electrical power from the system. A shock
hazard may still exist when enclosure panels or covers are removed.
Fig. 5.3.1.b – An Emergency Stop (E-Stop) does not cut all electrical power to equipment.

2.3.2 Shock Hazard Labeling

a. Modern laboratory equipment that meets product safety codes and standards is
required to be labeled with warning about electrical hazards. The international
symbol for a shock hazard is found in Fig. 5.3.2.a.

Fig. 5.3.2.a – International Symbol for a Shock Hazard

b. However, with legacy laboratory equipment, or with new equipment that is not
listed by an NRTL and that has not yet been inspected under PUB-3000
Chapter 14, Electrical Equipment Safety Program, sufficient labeling may or
may not be in place. The user should use caution when opening equipment.
 When unsure, contact a QEW for assistance.

c. Actual shock hazard warnings may or may not be applied on all equipment
enclosure panels. While Berkeley Lab electrical equipment inspectors apply
additional shock hazard warning labels to
equipment, many panels are not necessarily labeled with shock hazard
warnings. Note that if a panel requires a TOOL or KEY to access, labeling is
not required by product safety codes. Do not open panels with a tool or key
unless you know there is no electrical hazard. Consult with a QEW for a proper
determination. Typical labeling to watch for includes the samples in Fig.
5.3.2.c.
Fig. 5.3.2.c– Typical Hazard Warning Labels Found on Electrical Equipment
2.3.3 Sometimes it is necessary to open electrical equipment to perform non-
electrical work that does not require a QEW. However, the electrical hazard
must be isolated, controlled and verified safe prior to work. This is called
“establishing an Electrically Safe Work Condition”.

a. Hard-wired equipment will need to be locked out by a QEW in

accordance with the EHS Lockout/Tagout Program. Equipment that has
been inspected under the EESP will be labeled according to Fig. 5.3.3.a.

Fig. 5.3.3.a – Example of label applied to hard-wired equipment, indicating

requirement to lock out prior to servicing.

b. In general, cord-and-plug equipment can be placed in an Electrically Safe

Work Condition by a non- QEW when there is no stored hazardous electrical
energy. This is done simply by unplugging the equipment. Zero Voltage
Verification (ZVV) by a QEW is not required. Cord-and-plug equipment that
has been inspected under the EESP will be labeled according to Fig. 5.3.3.b.

Fig. 5.3.3.b – Example of label applied to cord-and-plug equipment, indicating

requirement to unplug prior to servicing.

c. Further, in accordance with the Lockout/Tagout Program, Work

Process C, Cord-and-Plug Equipment, cord-and-plug equipment is
 exempt from LOTO controls when:
 All hazardous energy is controlled by unplugging the equipment.
 The plug(s) remain(s) under exclusive control of the worker performing the
work.

d. If there is stored electrical energy greater than the capacitor thresholds in Table
2.2.13 (>10 J and
>100V), then the cord-and-plug exemption does not apply and there must
be a Complex LOTO Procedure that includes safe discharge verification
by a QEW.
  Note: For cord-and-plug 115 VAC chassis equipment, there is no stored
energy hazard if the following conditions are met:
- all voltage outputs are less than 100 VDC, and
- there is no mechanical, video or radiation output
 Stored energy hazards can be analyzed using the methods in 15.3.6.
Contact a QEW or an ESO for help if necessary.

Fig. 5.3.3.d – Example of label applied to equipment, indicating stored energy from
capacitors above the shock threshold.

e. If there is more than one power source (multiple plugs), take special care to
ensure that exclusive control can still be maintained by the person doing the
work. If exclusive control cannot be maintained, then a Complex LOTO
Procedure must be developed and used.
2.4 Portable electric equipment

2.4.1 This section applies to the use of cord- and plug-connected utilization
equipment, including cord sets (extension cords).

2.4.2 Handling. Portable equipment shall be handled in a manner that will not cause
damage.

a. Flexible electric cords connected to equipment shall not be used for

raising or lowering the equipment.

b. Flexible cords shall not be fastened with staples or hung in such a fashion as
could damage the outer jacket or insulation.

2.4.3 Grounding-Type Equipment.

a. A flexible cord used with grounding-type utilization equipment shall

contain an equipment grounding conductor.

b. Attachment plugs and receptacles shall not be connected or altered in a manner

that would interrupt continuity of the equipment grounding conductor.
Additionally, these devices shall not be altered in order to allow use in a
manner that was not intended by the manufacturer.

c. Adapters that interrupt the continuity of the equipment grounding conductor shall
not be used.

2.4.4 Visual Inspection of Portable Cord- and Plug- Connected Equipment and Flexible
Cord Sets.

a. Frequency of Inspection. Before each use, portable cord- and plug-connected

equipment shall be visually inspected for external defects (such as loose
parts or deformed and missing pins) and for evidence of possible internal
damage (such as a pinched or crushed outer jacket).
 Exception: Cord- and plug-connected equipment and flexible cord sets
 (extension cords) that remain connected once they are put in place and
are not exposed to damage shall not be required to be visually inspected
until they are relocated.

b. Defective Equipment. If there is a defect or evidence of damage that might

expose an employee to injury, the defective or damaged item shall be
removed from service and no employee shall use it until repairs and tests
necessary to render the equipment safe have been made.

c. Proper Mating. When an attachment plug is to be connected to a receptacle

(including on a cord set), the relationship of the plug and receptacle contacts
shall first be checked to ensure that they are of mating configurations.

2.4.5 Conductive Work Locations (Damp or Wet)

a. Conductive work locations are typically classified as damp or wet. Equipment used
in such locations
 must be rated accordingly. Most office and laboratory equipment is rated
“For Indoor Use Only”, which precludes damp or wet locations unless
additional measures are taken.

b. Wet locations include anywhere outdoors and anywhere within 3 feet of a

liquid source where splashing is likely (such as emergency showers, eyewash
stations, and some laboratory sinks with washdown hoses).

c. Damp locations include anywhere that is protected from direct exposure to the
elements but not necessarily in an indoor environment with HVAC atmosphere
controls. This can include garages, sheds, lean-tos and similar structures. Damp
locations also include anywhere within 6 feet of a liquid source (such as
emergency showers, eyewash stations, and sinks).

d. Portable electric equipment used in damp or wet locations, or in job locations

where employees are likely to contact water or conductive liquids, shall be
rated for damp or wet locations, or:
 Equipment placed in damp locations that is not rated for the wet location
must be protected with a GFCI.
 Equipment placed in wet locations that is not rated for the wet location
must be protected with a GFCI and a splash guard.

Pic 5.4.5.d – This listed equipment is rated for “FOR INDOOR USE
ONLY”.
 e. In job locations where employees are likely to contact or be drenched with
water or conductive liquids, ground-fault circuit-interrupter (GFCI) protection
for personnel shall also be used (see 5.8.3).

f. For temporary tasks, portable tools and equipment powered by sources other
than 120 VAC, such as batteries, air, and hydraulics, should be used to
minimize the potential for injury from electrical hazards for tasks performed in
conductive or wet locations.

2.4.6 Connecting Attachment Plugs.

a. Employees’ hands shall not be wet when plugging and unplugging flexible
cords and cord- and plug- connected equipment if energized equipment is
involved.
 b. Energized plug and receptacle connections shall be handled only with
insulating protective equipment if the condition of the connection could
provide a conductive path to the employee’s hand (for example, if a cord
connector is wet from being immersed in water).

c. Locking-type connectors shall be secured after connection.

2.4.7 Overcurrent protection of circuits and conductors may not be modified, even
on a temporary basis, beyond that permitted by applicable portions of
electrical codes and standards dealing with overcurrent protection.

2.4.8 Rating of equipment.

a. Portable electric equipment and its accessories shall be rated for circuits and
equipment to which they will be connected. Check the equipment nameplate
for rating information. This will typically include voltage, amperes, and
wattage.

b. Equipment marked “FOR INDOOR USE ONLY” is not suited for use
outdoors, in construction, or in damp or wet environments.

2.5 Extension cords for temporary use

2.5.1 Extension cords are for temporary use only and shall not take the place of
permanent wiring. Temporary use is constrained by the NEC, Article 590,
Temporary Installations.

2.5.2 When equipment is no longer being used, the extension cord should be
unplugged and stored. Where equipment is intended to stay in a specific
location, and a receptacle is not located close enough to plug in the equipment,
submit a work order request to have a receptacle installed where needed.

2.5.3 Time Constraints

a. Portable equipment usage: temporary wiring can be used while the equipment is
 used.

b. Construction: temporary wiring can be installed for the duration of construction.

c. Experiment: temporary wiring can be installed for the duration of experiments

and developmental work.

a. Emergencies and tests: temporary wiring can be installed for the duration of
emergencies and tests,

b. Holiday lights: temporary wiring can be installed for a maximum of 90 days.

2.5.4 Extension cords shall not be permanently attached to building surfaces, or
concealed in walls, floors, or ceilings, or located above suspended or dropped
ceilings.

2.5.5 Extension cords shall not be installed in raceways (conduit or cable tray).

2.5.6 Listing

a. Cord sets shall be listed by an NRTL, or

b. Where special circumstances require fabrication of a custom cord set, it shall

be fabricated by a QEW Electrician and shall meet the requirements of wire
gauge and length for the load as set in Table 5.5.15. Selection of materials
shall be made in accordance with UL 817, Standard for Safety, Cord Sets and
Power Supply Cords.

2.5.7 Only two extension cord sets may be daisy chained, unless they are equipped with
locking connectors rated for the environment. When daisy chaining cords, the
gauge of all cords shall be rated for the total length per 5.5.15.

2.5.8 Protection from damage

a. Extension cords shall be protected from accidental damage. Sharp corners and
projections shall be avoided. Where passing through doorways or other pinch
points, protection shall be provided to avoid damage.

b. An outdoor-use extension cord is intended to be used in conjunction with

portable electric equipment that is intended for use outdoors. The extension
cord is intended for use outdoors only while the portable equipment is in
operation. It is intended to be stored indoors where it is not exposed to
sunlight, weather, or both while not in use. It can also be used indoors.

2.5.9 Extension cord markings:

a. Cord markings determine the type and service duty of a cord.

b. All cord sets, whether for indoor or outdoor use, shall be of hard-service or
junior hard-service only and shall have one of the following markings: SOW,
SOOW, STW, STOW, STOOW, SEW, SEOW, SEOOW, SJOW, SJOOW,
SJTW, SJTOW, SJTOOW, SJEW, SJEOW, or SJEOOW.

c. Cord sets for construction sites shall be of hard-service only and shall have
one of the following markings: SOW, SOOW, STW, STOW, STOOW,
SEW, SEOW, or SEOOW.
 Markin Meani
g ng
S Hard-service cord, rated for 600 V
SJ Junior hard-service cord, rated for 300 V
E Thermoplastic elastomer
T Thermoplastic
O Oil-resistant outer jacket
OO Oil-resistant outer jacket and oil-resistant
insulation
W Weather and water resistant (suitable for
outdoor use)

“(UL)” – this cord is NRTL-

listed
“12/3” – 12 AWG, 3-conductor
“SJTW” – Junior hard
service, Thermoplastic,
Weather and water resistant.
Suitable for outdoor use but
not for construction sites.

2.5.10 Before Use

a. Inspect thoroughly before each use. Do not use if damaged. Use only properly
maintained extension cords that have no exposed live parts, exposed
ungrounded metal parts, damage, or splices.

b. A cord set that is not marked “FOR OUTDOOR USE” is to be used indoors
only, and shall not be used on construction sites.

c. Look for the number of watts on appliances to be plugged into cord. See
product or label markings for specific wattage. Do not plug more than the
specified number of watts into this cord.

d. Route the cord in a way that avoids tripping hazards.

e. Make sure appliance is off before connecting cord into outlet.

 f. Fully insert plug into outlet. Do not use excessive force to make connections.

g. Do not connect a three-prong plug to a two-hole cord.

h. Do not remove, bend, or modify any metal prongs or pins of cord.

2.5.11 During Use

a. Keep away from water.

b. Do not use when wet.

 c. Avoid overheating. Uncoil cord and do not cover it with any material.

d. Do not drive, drag or place objects over cord.

e. Do not walk on cord.

2.5.12 After use

a. Always unplug when no longer needed.

b. Grasp plug to remove from outlet. Do not pry the plug by sticking the fingers
between the receptacle and plug face, as this could cause an electrical shock.
Do not unplug by pulling on cord, as this could damage the plug.

c. Make sure the grounding prong is present in the plug. Make sure the plug
and receptacle are not damaged.

d. Wipe the cord clean and examine for cuts, breaks, abrasions, and defects in the
insulation.

e. Always store the cord indoors, even if the cord is marked for outdoor use. Coil
or hang the cord for storage. Coiling or hanging is the best way to avoid tight
kinks, cuts, and scrapes that can damage insulation or conductors.

2.5.13 Repairs

a. Only qualified electrical workers may make repairs of extension cords.

b. Never splice extension cords, even for a repair. If an extension cord is

damaged, it may be made into two cords, provided the proper connectors are
used in a proper manner.

c. Only qualified personnel may install cord caps for use with potentials greater than
50 V.

2.5.14 Grounding
 a. Always use three-conductor (grounded) cord sets—even if the device has a
two-conductor cord. Never use two-conductor extension cords at the
Laboratory.

b. Do not cut off the ground pin of a cord set or compromise the ground protection in
any way.

c. Do not use extension cords with a ground conductor that has less current-
carrying capacity than the other conductors.

2.5.15 Amperage

a. Use of an undersized cord results in an overheated cord and insufficient

voltage delivered to the device, thus causing device or cord failure and a fire
hazard. An undersized cord also constitutes a
 serious shock hazard, as it may not allow the breaker feeding it to trip.

b. Make sure that the wire size is sufficient for the current and distance required.
See Table 5.5.15 for recommended extension cord sizes for portable electric
tools.
 This table is copied from NFPA 70B-2013, Table 29.5.1. Size is based on
current equivalent to 150 percent of full load of tool and a loss in voltage
of not over 5 volts.
 If voltage is already low at the source (outlet), voltage should be
increased to standard, or a larger cord than listed should be used to
minimize the total voltage drop.

Extensi Nameplate Ampere

on Rating
Cord 0-2.0 2.1-3.4 3.5-5.0 5.1-7.0 7.1- 12.1-
Lengt Amps Amps Amps Amps 12.0 16.0
Amps Amps
h (ft) 115 230 115 230 115 230 115 230 115 230 115 230
V V V V V V V V V V V V
25 18 18 18 18 18 18 18 18 16 18 14 16
50 18 18 18 18 18 18 16 18 14 16 12 14
75 18 18 18 18 16 18 14 16 12 14 10 12
100 18 18 16 18 14 16 12 14 10 12 8 10
200 16 18 14 16 12 14 10 12 8 10 6 8
300 14 16 12 14 10 14 8 12 6 10 4 6
400 12 16 10 14 8 12 6 10 4 8 4 6
500 12 14 10 12 8 12 6 10 4 6 2 4
600 10 14 8 12 6 10 4 8 2 6 2 4
800 10 12 8 10 6 8 4 6 2 4 1 2
1000 8 12 6 10 4 8 2 6 1 4 0 2
Table 5.5.15 – Recommended Wire Size (AWG) For Extension Cords

2.6 Relocatable Power Taps (Power Strips)

2.6.1 A relocatable power tap (RPT, also referred to as a power strip or multiple outlet
strip) is an electrical enclosure with an attached power supply cord and
attachment plug for connection to a permanently installed branch circuit
receptacle outlet, and provided with one or more receptacle outlets. There are no
 time constraints on how long RPTs may remain connected to a branch circuit
receptacle outlet.

2.6.2 These requirements cover cord-connected, relocatable power taps rated 250 VAC
or less and 20 A or less. A relocatable power tap is intended only for indoor use
as an extension of a grounded alternating- current branch circuit for general use.
Pic. 5.6.2 - Example of a Relocatable Power Tap (RPT)

2.6.3 Only use NRTL-labeled relocatable power taps.

a. All RPTs are listed to UL 1363, Standard for Safety, Relocatable Power Taps.

b. Custom fabricated relocatable power taps shall not be permissible.

c. Listed RPTs will typically have a UL sticker on the back such as the one in
Pic. 5.6.3, stating “Listed Power Tap”. RPTs that also have surge suppression
are dual-listed for Transient Voltage Surge Suppression (TVSS).

Pic. 5.6.3, Labeling and markings on the back of a listed relocatable power tap
d. Note that Power Distribution Units (PDU’s) for Information Technology
Equipment are for permanent installation and are listed to a different
standard, UL 60950, Standard for Safety, Information Technology Equipment
– Safety – Part 1: General Requirements. This section does not apply to
PDU’s.
2.6.4 Usage

a. Relocatable power taps are for indoor use only, and not approved for
construction sites or for outdoor use.

b. In technical spaces such as electrical rooms, machine rooms, machine shops

and laboratory spaces, RPTs shall only be used to power low-powered loads,
such as computers, peripherals, or audio/video components. Bench top
laboratory or testing equipment may also be powered from RPTs provided
they do not exceed the maximum load of 5.6.5.d.

c. Relocatable power taps may only be plugged directly into a permanent

receptacle outlet (no daisy- chaining):
 Do not plug a relocatable power tap into another relocatable power tap.
 Do not plug a relocatable power tap into an extension cord.

d. Where a relocatable power tap is not permitted, the following options are available:
 Move the equipment closer to a permanent receptacle.
 Procure a relocatable power tap with a longer cord (commercially
available with up to 25 foot cords).
 Have a permanent receptacle installed closer to the equipment.
 For temporary use only (see 5.5), use an extension cord with multiple
outlets, an adapter cord set, or a power distribution box rated for the
load and environment.

2.6.5 Amperage

a. Exceeding the load rating of the device or outlet could introduce a fire hazard.

b. The total connected amperage load of the RPT shall not exceed its rating,
regardless of whether all the equipment is used simultaneously or not (100%
load factor).

c. Refer to limitations of use marked on the data plate of the device. Do not
exceed the load rating of the device.
 d. Equipment rated at greater than 600 Watts (5 Amps) must be plugged directly
into a wall receptacle whenever possible. Do not use RPT’s for this purpose.
This includes most space heaters, hotplates, refrigerators, microwave ovens and
coffee pots.

2.6.6 Mounting

a. Do not permanently mount relocatable power taps to any facility surface.

b. It is acceptable to hang them from screws or hooks if they are manufactured with
slots or keyholes.

c. It is acceptable to attach them with Velcro or any means that will not require the
use of a tool to
 remove.

d. It is not acceptable to use wire ties for mounting, as this is considered a permanent
installation.

e. In equipment racks, the preferred method of supplying 120/208-V utility

power to rack-mounted instruments is via a special relocatable power tap
specifically designed to be rack-installed.

2.7 Adapter Cord Sets

2.7.1 An adapter cord set is intended for use at locations such as construction sites
and is designed to convert one plug to 2 or 3 single-outlets of the same
configuration as the plug or convert to another configuration.

Pic 5.7.1 – Examples of Adapter Cord Sets

2.7.2 Adapter cord sets are marked “Intended for use on construction sites and similar
locations.”

2.7.3 Care shall be taken to not overload either the branch circuit or any part of the
assembled system of cord set(s) and adapter cord set(s).

2.7.4 When combining adapter cord sets and extension cord sets (which can also have
multiple cord connectors at the load end), there shall be no more than 6 total
available receptacles to which a tool or appliance can be plugged in. If the adapter
cord set is placed at the load end of the extension cord set, the extension cord set
 shall be at least 12 AWG and no more than 100 feet long.

2.8 Ground Fault Circuit Interrupters

2.8.1 A Ground Fault Circuit Interrupter (GFCI) is a safety device designed to limit
line-to-ground shock current to less than 5 mA. Listed devices are designed to
trip between 4-6 mA in less than 20 msec.

2.8.2 Principle of Operation

a. GFCIs are devices that sense when current—even a small amount—passes to

ground through any path other than the proper conductor. When this condition
exists, the GFCI quickly opens the circuit,
 stopping all current flow to the circuit and to a person receiving the ground
fault. Figure 5.8.2 shows a typical circuit arrangement of a GFCI designed to
protect personnel. The incoming two-wire circuit is connected to a two-pole,
shunt-trip overload circuit breaker.

Fig. 5.8.2 – Principle of GFCI Operation

b. The load-side conductors pass through a differential coil onto the outgoing
circuit. As long as the current in both load wires is within specified tolerances,
the circuit functions normally. If one of the conductors comes in contact with a
grounded condition or passes through a person's body to ground, an unbalanced
current is established. In Fig. 5.8.2, 1 amp of ground fault current is flowing
out of the circuit. The differential transformer picks up this unbalanced current,
and a current is established through the sensing circuit to energize the shunt
trip of the overload circuit breaker and quickly open the main circuit.
c. A fuse or circuit breaker cannot provide this kind of protection. The fuse or
circuit breaker trips or opens the circuit only if a line-to-line or line-to-ground
fault occurs that is greater than the circuit protection device rating.

d. Differential transformers continuously monitor circuits to ensure that all

current that flows out to motor or appliances returns to the source via the
circuit conductors. If any current leaks to a fault,
 the sensing circuit opens the circuit breaker and stops all current flow.

e. A GFCI does not protect the user from line-to-line or line-to-neutral contact
hazards. For example, if an employee using a double-insulated drill with a
metal chuck and drill bit protected by a GFCI device drills into an energized
conductor and contacts the metal chuck or drill bit, the GFCI device does not
trip (unless it is the circuit the GFCI device is connected to) as it does not
detect a current imbalance.

2.8.3 Where required5:

a. Outdoors: Use a GFCI when working outdoors and operating or using cord-
and plug-connected equipment supplied by 125-volt, 15-, 20-, or 30-ampere
circuits. For other types of circuits, contact the EHS Electrical Safety Group
for guidance.

b. Indoors: Use a GFCI around construction sites, in wet or damp areas, or in an

area where a person may be in direct contact with a solidly grounded
conductive object (e.g., working in a vacuum tank). Wet or damp areas include
areas within 6 feet of a sink, shower, emergency eyewash station or other
water source, but do not include fire sprinklers.

c. GFCI protection devices shall be tested in accordance with the manufacturer’s

instructions.

d. Where GFCI protection is not permanently installed, portable GFCI protection is

acceptable.

e. Permanently installed GFCIs take the form of GFCI receptacles or GFCI

circuit breakers. Standard receptacles that are protected by an upstream GFCI
must be marked “GFCI PROTECTED OUTLET”.
5
The National Electric Code requires installation of permanent GFCI protection in
certain areas. The list of areas where permanent GFCIs are required grows every code
cycle but is not retroactive to old installations. However, NFPA 70E requires the use of
GFCI protection in conductive work locations (5.4.5) and in all locations currently
required by the latest edition of the NEC. This means that portable GFCI protection must
be used wherever an older NEC code of record did not require permanent GFCI
installation.
 f. Portable GFCIs consist of either plug-mounted GFCI devices or portable
inline GFCI devices. When using a portable inline GFCI, it shall be placed
between the receptacle and the cord.

g. It is best practice to always use GFCI protection with portable electric hand
tools even when not required. GFCI protection is permitted to be used in any
location, circuit, or occupancy to provide additional protection from line-to-
ground shock hazards.

2.8.4 Auto-reset feature:

a. There are two types of portable GFCI’s. Some have an automatic reset and some
do not.

b. For temporary use with extension cords and power tools, use a portable GFCI
without an auto-reset feature. This requires the user to test the device by
resetting it every time the device is plugged in.
 c. For permanent use where a GFCI receptacle or breaker is not installed,
consider using a portable GFCI with an auto-reset feature. This is especially
critical for loads that should restart automatically after a short power outage,
like refrigerators.

2.8.5 Tripped GFCI

a. When a GFCI has tripped, it is usually an indication that there is a problem

with a short to ground. Examine the equipment to see if there are any wet
areas that may be causing the trip. It is okay to reset the GFCI. If it trips
again, call a QEW to investigate.

b. If you suspect that the equipment design is causing current leakage, contact
the Electrical Safety Group and schedule an inspection of the equipment.

c. Do no continue to reset the GFCI if it trips repeatedly. Stop work and call a QEW
to investigate.

d. Do not bypass a GFCI or look for a non-GFCI protected outlet if a GFCI trips
repeatedly. The tripping is a sign of a potentially fatal shock hazard and should
be evaluated carefully. Stop work and call a QEW to investigate.

2.8.6 Testing a GFCI

a. The actual test of a GFCI is very simple and can be done safely by anyone.
Apply a load (such as a night light or lamp) to the GFCI, press the TEST
button, and verify the load trips off. Press the RESET button and verify the
load comes back on.

b. In general, GFCIs are required to be tested “in accordance with manufacturer’s

instructions”. Today’s manufacturers require monthly testing. While monthly
testing may not be practicable due to the sheer number of devices and the
repeated power disruption to the loads, users should know that the typical
failure rate for GFCIs is fairly high, somewhere between 10-25% over just a
few years use.
c. Best practice:
 Portable inline GFCIs: test every time it is used. Portable GFCIs without
an auto-reset feature require resetting anyways when initially plugging
in. Test the GFCI once more after the initial reset.
 Receptacle GFCIs: if you have not used this receptacle before, test the
GFCI before plugging in a device. However, be aware that some GFCIs
provide downstream protection for other receptacles. Testing will
interrupt the power to all downstream devices.
 Plug-mounted GFCI’s: test every time it is used. If used frequently, test
monthly.

d. If a GFCI fails the test, either through obvious mechanical jamming of the
buttons or failure to interrupt the load, call a QEW Electrician for a repair.
2.9 Heating Tapes and Cords

2.9.1 Many experiments at Berkeley Lab use heating tapes or cords, including many
high-vacuum apparatuses. The heating tapes or cords pose an electrical shock
hazard if not used properly. This section also applies to heating pads, wraps, or
similar components intended to be applied directly to a laboratory apparatus.

2.9.2 General Electrical Safety Requirements for Use of Heating Tape

a. Whenever possible, use heating tapes that bear a listing mark by UL or another
NRTL.

b. Use three-wire (grounded) heating tape and cord systems whenever practical.
Two-wire heat tapes and cords, while allowed for use at LBNL, are inherently
less safe than three-wire systems.

c. Inspect heating tapes and cords before use and discard any that display
signs of excessive wear, fraying, or overheating. Do not repair damaged
items.

d. Properly ground all conductive equipment surfaces before heating tapes are
powered.

e. Equipment undergoing heating with a variable AC transformer controlled

heat tape must be monitored on a regular basis to prevent overheating of
either the chamber or the heating device.

f. Heating tapes and cords with an AC plug that can be split into two pieces
must have the plug replaced or glued together.

g. Read all the manufacturer’s instructions before using any heating device.

h. Do not plug heating tape directly into a receptacle. There must be some type of
controller such as a variac or a heat controller system.
 i. Use heat tapes only on surfaces for which they are designed. Glas-Col®
heating cords are an example of a cord that may not be used at LBNL for
any purpose but heating glassware and nonmetallic apparatuses.

j. If you are unsure whether or not your heating tape or cord is approved for
use at LBNL, refer to PUB-3000 Chapter 14, Electrical Equipment Safety
Program or contact the EHS Electrical Safety Group.

2.9.3 Heating Tape Power Source Requirements

a. A ground fault current interrupter (GFCI) protected power source must be

used. Portable GFCI adaptors are acceptable.

b. A maximum of 1920 W (16 A) of heating capacity may be placed on a 20-amp

circuit breaker.
 c. A maximum of 1440 W (12 A) heating capacity may be placed on any
individual power cord or receptacle

d. Do not use relocatable power taps (power strips) for heating tape.

2.10 Portable Heating Devices

2.10.1 Use of portable electric heating devices is covered by PUB-3000, Chapter

12, Fire Prevention and Protection, Work Process I, Portable Heating
Devices. It includes include portable electric space heaters, coffee pots, and
hot plates.

2.11 Holiday Lights

2.11.1 Holiday lights are permitted for temporary installation up to 90 days in

office areas. They are not permitted in laboratory areas or technical spaces.

2.11.2 Always use GFCI protection on holiday lights.

2.11.3 Do not staple holiday lights.

2.11.4 Holiday lights are designed to be daisy-chained. Observe the maximum total
load restrictions when daisy-chaining holiday lights.

2.12 Working Space Around Electrical Equipment

2.12.1 Clear Spaces. Working space required by this section shall not be used for storage.

2.12.2 Working space around electrical enclosures or equipment shall be adequate for
conducting all anticipated maintenance and operations safely, including sufficient
space to ensure safety of personnel working during emergency conditions and
workers rescuing injured personnel.

2.12.3 Spacing shall provide the dimensional clearance (addressed in the following
subsections) for personnel access to equipment likely to require examination,
 adjustment, servicing, or maintenance while energized. Such equipment includes
panelboards, switches, circuit breakers, switchgear, controllers, and controls on
heating and air conditioning equipment.

2.12.4 These working clearances are not required if the equipment is not likely to require
examination, adjustment, servicing, or maintenance while energized. However,
sufficient access and working space is still required.

2.12.5 Dead-Front Assemblies

a. Working space shall not be required in the back or sides of assemblies, such
as dead-front switchboards, switchgear, or motor control centers, where all
connections and all renewable or
 adjustable parts, such as fuses or switches, are accessible from locations
other than the back or sides.

b. Where rear access is required to work on nonelectrical parts on the back of

enclosed equipment, a minimum working space of 30 in horizontally shall be
provided.

2.12.6 Working spaces may overlap.

2.12.7 Height of Working Space

a. The working space shall be clear and extend from the grade, floor, or platform
to a height of 6½ ft or the height of the equipment, whichever is greater.

b. Within the height requirements of this section, other equipment that is

associated with the electrical installation and is located above or below the
electrical equipment shall be permitted to extend not more than 6 in beyond
the front of the electrical equipment.

2.12.8 Width of Working Space

a. A minimum working space 30 inches wide shall be provided in front of

electrical equipment rated at 600 V or less and is likely to require servicing
while energized. This provides room to avoid body contact with grounded parts
while working with energized components of the equipment.

b. The width of the working space may be centered in front of the equipment
or can be offset. The depth of the working space shall be clear to the floor.

c. For equipment rated above 600 V, the width of the working space shall be 36
inches.

d. In all cases, there shall be clearance in the work area to allow at least a
90-degree opening of equipment doors or hinged panels on the service
equipment.
 Depth varies

Fig. 5.12.7 – Working space in front of a panelboard <600 V. Depth varies depending on
Voltage and Condition.

2.12.9 Depth of Working Space

a. The depth of the working space varies depending upon existing conditions (Table
5.12.9, Fig. 5.12.9).

b. Condition 1: Exposed live parts on one side of the working space and no live
or grounded parts on the other side of the working space, or exposed live
parts on both sides of the working space that are effectively guarded by
insulating materials.

c. Condition 2: Exposed live parts on one side of the working space and
grounded parts on the other side of the working space. Concrete, brick, or tile
walls shall be considered as grounded.

d. Condition 3: Exposed live parts on both sides of the working space.

 Condition 1 Condition 2

Condition 3 Fig 5.12.9 – Illustration of

Conditions for Working Clearance

Minimum Depth of Working Clearance in Front

of Panel Face
Volts to Ground Conditio Conditio Conditio
n1 n2 n3
0-150 V 3 ft 3 ft 3 ft
151-600 V 3 ft 3.5 ft 4 ft
601-2500 V 3 ft 4 ft 5 ft
2501-9000 V 4 ft 5 ft 6 ft
9001-25000 V 5 ft 6 ft 9 ft
Table 5.12.9 – Minimum clearances in front of electrical equipment
2.13 Switching

2.13.1 This section concerns the switching of electrical disconnects and circuit breakers
for normal operation of electrical equipment.

2.13.2 All non-QEWs who perform switching on premises wiring panelboards or any
circuit breaker or fused disconnect rated at 15 Amps or greater must take the
class EHS0536 – Electrical Switching Safety for non-QEWs.

2.13.3 Switching is the manual operation (opening or closing) of any electrical

isolation on energized equipment. Manual operation includes the operation of
through-the-door breaker handles or other dead-front switching.

2.13.4 Non-QEWs are permitted to perform switching on panelboards and local

equipment disconnect switches (fused disconnects or circuit breakers) where
there is no shock or arc flash hazard. To help non-QEWs in determining when
switching is allowed, the following rules are established. These rules are more
restrictive than the rules established in Sections 7 or 8, which are applied by
QEWs.

a. For more information on determining a shock hazard or an arc flash

hazard, see Sections 7 or 8 respectively and contact a QEW for assistance.

b. Non-QEWs are not authorized to perform switching of power circuit breakers in

switchgear.

2.13.5 Determination of a shock hazard for switching

a. Check the condition of the panel enclosure. Switching is allowed where the
panel is fully enclosed and in good repair. There can be no visible exposed
live parts. Covers must be latched tight and all fasteners must be in place.

b. Finger safe rating is not sufficient for switching of disconnects inside enclosures by
non-QEWs.
2.13.6 Determination of an arc flash hazard for switching

a. An arc flash hazard is a dangerous condition associated with the possible

release of energy caused by an electric arc, resulting in second-degree burns
to the skin or ignition of clothing. An arc flash hazard may exist when
performing normal switching of electrical equipment.

b. Where a panelboard or disconnect switch is labeled with an arc flash label,

check the incident energy at the working distance. Switching is allowed where
the incident energy is 4 cal/cm2 or less.
c. Where the panelboard or disconnect switch is not labeled with an arc flash
label, contact the Facilities Engineering Department for assistance getting an
arc flash label. If switching is required before the label is available, check the
panel voltage and main circuit breaker or fuse amp ratings. Switching is
allowed where:
 Voltage 120 VAC or less – all cases
 Voltage 250 VAC or less and main breaker or switch rating 250 A or less
 Voltage 750 VAC or less and main breaker or switch rating 60 A or less

d. In all other cases, a Qualified Electrical Worker is required to perform the

switching.
Pic – In this case, the panel is not labeled with arc flash energy. However, it is a 120/208
VAC panel and the main breaker is rated for only 100 A, so non-QEWs are allowed
to perform switching in this panel.

2.13.7 Minimum PPE: the minimum PPE for electrical switching is a leather glove on
the switching hand and safety glasses.

2.13.8 Switching method: when performing switching, the worker will take the
following standard precautions:

a. Stand to the side. Where possible, do not reach across the panel to the switch
handle, instead stand on the same side of the panel as the switch handle.

b. Place hand on the switch handle but do not operate the switch.

c. Face away from the switch, close the eyes, take a deep breath and hold it.

d. Forcefully throw the switch in a complete full motion.

e. Verify system response.

2.13.9 Tripped circuit breakers. The following applies to molded case circuit breakers
commonly operated by non-QEWs.

a. Circuit breakers are designed to trip for two types of overcurrent condition:
overload and short- circuit.

b. In an overload condition, the thermal element will open the breaker after a
certain time depending on the amount of overload. This can take anywhere
from an hour (135% overload) to a couple of
 minutes (200% overload). This action protects the wiring insulation from
overheating and causing a fire. This can happen when multiple high current
loads are run at the same time on the same circuit. For example, running a
space heater, a coffee maker, and a microwave at the same time.

c. In a short-circuit condition, the breaker is subjected to a high current surge

(>2000 Amps) and uses the resulting magnetic impulse to trip the breaker
instantaneously. This can happen either by a ground fault (for grounded
equipment) or a phase to neutral short. It is important to note that while
breakers are rated to interrupt a short circuit once without failing, it is possible
(even likely) that they will fail catastrophically should they be reclosed on short
circuit. This can result in injury to the hands and face.

d. If it is readily apparent that the circuit breaker tripped on an overload

condition, correct the condition by removing the excess load. After removing
the excess load, reset and close the breaker. If the circuit breaker trips again,
leave it alone and call a Qualified Electrical Worker for assistance.

e. If there is no apparent cause of overload, do not assume that the breaker can
be reclosed, even once. Leave the breaker alone and call a Qualified
Electrical Worker for assistance.

f. See 10.4.13 for more information on reclosing circuits after protective device
operation.

2.13.10 Switching of Fluorescent Lighting

a. For routine switching of fluorescent lighting, do not use circuit breakers in

panel boards unless these are specifically rated for switching duty.

b. A switching duty (SWD) circuit breaker is listed under UL 489 specifically

for switching fluorescent lighting loads on a regular basis.

c. SWD circuits breakers can be identified by a “SWD” marking on the front

or side of the breaker. However, panel board trim pieces may need to be
 temporarily removed by a QEW for visual confirmation.

d. Note that there are no 480 VAC, 3-phase SWD breakers. SWD circuit breakers
are limited to 15 or 20 Amps and less than 347 Volts.
3 Electrical Safe Work Controls

3.1 Scope

3.1.1 This section establishes the necessary work planning and control requirements
for Qualified Electrical Workers (QEWs) performing electrical work.

3.2 Qualified Electrical Workers (QEWs)

3.2.1 A Qualified Electrical Worker (QEW) is one who has demonstrated skills and
knowledge related to the construction and operation of electrical equipment and
installations, has received safety training to identify and avoid the hazards
involved, and who has been approved by the Electrical AHJ for Safe Work
Practices.

3.2.2 Any person who is not a QEW is called a non-QEW.

3.2.3 Only QEWs may be authorized to perform electrical work (see 6.3.1) on
equipment designed to operate above the shock hazard thresholds of Table
2.2.13.QEWs shall be classified in accordance with Table 6.2.3, depending
primarily on the type of utility power feeding the equipment they perform
electrical work upon.

QEW Level Source Type

50 – 300 VAC, 50-60 Hz power,
QEW 1 (i.e. Researchers, provided there is no arc flash hazard
Fire Alarm Technicians
and Engineers)

QEW 2 (i.e. Lighting 50 – 750 VAC, 50-60 Hz power,

Electricians, HVAC, with or without arc flash hazard
Electricians, Electronics
Technicians and
 Electrical Engineers)

QEW 3 (i.e. High

Voltage Electricians >750 VAC Utility 60 Hz
and High Voltage
Electrical Engineers)

QEW R (Researchers) Other non-line exposure above the

thresholds of Table 2.2.13, not
otherwise categorized
Table 6.2.3 – QEW Levels
 a. QEW’s may be authorized to perform work at lower QEW levels, provided
that they meet all of the requirements for equipment specific training.

b. Determination of an arc flash hazard for the purposes of QEW 1 level

determination shall be done in accordance with Section 8.

3.2.4 AHJ approval of QEW’s

a. AHJ approval of QEWs shall be in accordance with PUB-3000, Chapter 8,

Electrical Safety Program, Work Process E, AHJ Approval of Berkeley Lab
QEWs. Some exceptions apply when non-QEWs perform work under the
supervision of a QEW.

b. Construction subcontractors tasked with performing electrical work under the

cJHA process are also required to be accepted as QEWs, and fall under PUB-
3000, Chapter 8, Electrical Safety Program, Work Process F, AHJ Acceptance
of Construction Subcontractor QEWs.

c. Vendors tasked with performing electrical work under the sJHA process are
also required to be accepted as QEWs, and fall under PUB-3000, Chapter 8,
Electrical Safety Program, Work Process G, AHJ Acceptance of Non-
Construction Subcontractor QEWs. Some exceptions apply when non-QEWs
perform work on their own equipment and under the supervision of a QEW.

d. The EHS Electrical Safety Group will issue a QEW badge to approved QEWs.
The badge is to be carried with the employee’s LBNL Badge. In addition to
name, photo, and employee ID number, the QEW Badge will indicate QEW
level and any restrictions on the approval.

3.2.5 Training requirements for QEWs shall be in accordance with PUB-3000,

Chapter 8, Electrical Safety Program, Work Process I, Electrical Safety
Training for Berkeley Lab QEWs.

3.3 Electrical Work and Requirement for a QEW

3.3.1 Electrical work is defined as any task that involves a shock or arc flash hazard or
could create potential shock or arc flash hazards for future users. A Qualified
Electrical Worker is required for all electrical work, with the following
exceptions:

a. Exception: Berkeley Lab personnel who only perform electrical work on

cord-and-plug equipment are not required to be accepted as QEWs provided:
 The equipment is unplugged.
 The equipment meets the requirements for the cord-and-plug exemption
to Lockout/Tagout (LOTO) in accordance with the Berkeley Lab ES&H
Manual Lockout/Tagout Program, Work Process C, Cord-and-Plug
Equipment.
 A QEW provides direct field supervision (6.11) of any electrical
work performed while equipment is unplugged.
  Personnel are trained and authorized by their line management to
perform the work on that specific equipment.

b. Exception: Berkeley Lab personnel who only perform electrical work on hard-
wired equipment that has been placed in an Electrically Safe Work Condition
are not required to be accepted as QEWs provided that:
 A QEW places the equipment in an Electrically Safe Work Condition.
 All persons join the LOTO in accordance with the Berkeley Lab ES&H
Manual Lockout/Tagout Program.
 The QEW provides direct field supervision (6.11) of any electrical work
performed while in an Electrically Safe Work Condition.
 The QEW performs Test Before Touch every time job continuity is
interrupted.
 Personnel are trained and authorized by their line management to
perform the work on that specific equipment.

3.3.2 Qualified Electrical Workers shall be required for the following tasks, which are
classified as electrical work:

a. Any modification, repair, build or assembly of electrical circuit parts or

wiring designed to operate above the shock thresholds of Table 2.2.13, even
after being placed in an Electrically Safe Work Condition. Examples include:
 Making or tightening electrical terminal connections with tools, as
poor or improper connection can create serious hazards.
 Any work on the grounding and bonding system
 Any work on the power entry module or field wiring terminals
 Replacing critical components with new components of different ratings.
Critical components include electrical components or assemblies used in a
power or safety circuit whose proper operation is essential to the safe
performance of the system or circuit (e.g. fuses, circuit breakers, power
wiring, transformers, heaters, motors, overloads, interlocks, emergency
stops, etc.).

b. Any operation of equipment that does not meet the requirements for normal
 operation of 6.3.5.

c. Hazardous switching, where there is a shock or arc flash hazard in accordance with
6.3.6.

d. Any task within the Restricted Approach Boundary of exposed live parts that
have not been placed in an Electrically Safe Work Condition, including
placing equipment in an Electrically Safe Work Condition.
3.3.3 Non-QEWs may perform the following types of tasks:

a. Normal operation of approved electrical equipment in accordance with 6.3.5.

b. Non-hazardous switching, where there is no shock or arc flash hazard in

accordance with 6.3.6.

c. Access within the Limited Approach Boundary of exposed live parts that have
not been placed in an Electrically Safe Work Condition, if escorted by a QEW
as required in 7.3.2.c.

d. Any task that does not involve the modification, repair, build or assembly of
electrical circuit parts or wiring designed to operate above the shock thresholds
of Table 2.2.13, within the Limited Approach Boundary of exposed live parts
that have been placed in an Electrically Safe Work Condition. Zero Voltage
Verification (ZVV) must be performed by a QEW and the non-QEW must
apply a personal LOTO lock in accordance with PUB-3000, Chapter 18,
Lockout/Tagout Program.

e. Voltage and current measurements below the shock hazard thresholds,

provided that they are outside of the Limited Approach Boundary or Arc
Flash Boundary of other exposed energized parts operating above the
thresholds.

3.3.4 Some tasks may or may not require a QEW, where the presence of a shock
or arc flash hazard is dependent on the configuration of the equipment.

a. Non-QEWs shall seek the help of a QEW or other knowledgeable individual

(like an Electrical Safety Advocate or supervisor) in determining whether such
a task requires a QEW. The Electrical AHJ for Safe Work Practices shall have
final authority over such determinations.

b. Typical R&D equipment may or may not have sufficient engineered safeguards
to mitigate shock or arc flash hazards when performing common tasks such as
adjusting system parameters in digital controllers with cabinet doors open while
 the system is energized. Where a shock or arc flash hazard is present, a QEW is
required.

c. Examples of tasks that may or may not require a QEW include:

 Work in proximity to energized components that are protected by finger
safe designs (see 7.2.3). A QEW is required to determine whether parts
are in fact finger safe for the scope of work being proposed.
 Like-for-like replacement of electrical components designed to be
user-serviceable by the manufacturer. This can include replacement of
bulbs, fuses, circuit boards, relays or other plug-and-play devices.
Some devices are designed to eliminate the hazard and require no
special tools or methods, and therefore could be performed by a non-
QEW.
 Adjusting variable speed drive control parameters in a cabinet with live
exposed 208 VAC. A QEW can apply temporary barriers over exposed
parts, allowing a non-QEW to safely perform the work.
3.3.5 Normal operation

a. Under normal operation of approved electrical equipment, the user/operator

is protected by engineering controls, including insulation, enclosures,
barriers, grounds and other methods to prevent injury. Approved means that
it has been accepted either by the Electrical AHJ for Safe Installations in
accordance with the Safe Electrical Installations Policy, or by the Electrical
AHJ for Safe Equipment in accordance with PUB-3000, Chapter 14,
Electrical Equipment Safety Program.

b. Where all of the following conditions are satisfied, normal operation of

electric equipment is not considered electrical work and shall be permitted
by non-QEWs:
 The equipment is properly installed, in accordance with applicable
industry codes and standards and the manufacturer's
recommendations.
 The equipment is properly maintained by qualified persons.
 The equipment doors are closed and secured.
 All equipment covers are in place and secured.
 There is no evidence of impending failure (10.4.10 and 10.4.11).

c. Where the conditions for normal operation are not satisfied, it is assumed that
a shock or arc flash hazard may exist when operating the equipment.
Operation by a non-QEW is not permitted.

3.3.6 Switching

a. Switching is the manual operation (opening or closing) of any electrical

isolation. This includes the operation of through-the-door breaker handles or
other dead-front switching.

b. Energized switching is classified as either hazardous or non-hazardous,

depending on whether a shock or arc flash hazard is present.

c. Non-hazardous switching is any switching where there is no shock or arc flash

 hazard. In all cases the conditions for normal operation must be satisfied for
non-hazardous switching. Non-QEWs may only be authorized to perform non-
hazardous switching. The restrictions in 5.13 are designed for a non-QEW to
be able to identify when safe switching can be performed. As an alternative, a
QEW may perform a shock and arc flash hazard analysis in accordance with
7.1 and 8.1 to determine if a non-QEW can perform safe switching in a
specific instance.

d. Hazardous switching, where a shock or arc flash hazard is present, is classified

as electrical work. Only QEWs may be authorized to perform hazardous
switching, wearing the appropriate level of PPE in accordance with the shock
and arc flash hazard analyses.

e. Where a QEW performs non-hazardous switching, only the minimum PPE of 5.13
shall be required.

f. In all cases, only load-rated switches, circuit breakers, or disconnects shall be

used for the opening, reversing, or closing of circuits under load conditions.
3.3.7 Types of Electrical Work. When engineering controls are not yet in place, not
approved, or removed for diagnostics, maintenance, or repair, work on electrical
equipment is classified as electrical work and falls into one of the following
modes. These modes are primarily used as short hand terminology for indexing
types of electrical work:

a. Mode 0 – Electrically Safe Work Condition

b. Mode 1 – Establishing an Electrically Safe Work Condition (LOTO)

c. Mode 2 – Energized Diagnostics (Testing & Troubleshooting)

d. Mode 3 – Energized Repair/Installation (EEWP)

3.4 Mode 0 – Electrically Safe Work Condition

3.4.1 An Electrically Safe Work Condition is a state in which an electrical conductor or

circuit part has been disconnected from energized parts, locked/tagged in
accordance with the Berkeley Lab Lockout/Tagout Program, tested by a QEW to
ensure the absence of voltage (Zero Voltage Verification – ZVV), and grounded if
determined necessary.

3.4.2 Work performed in an Electrically Safe Work Condition may or may not be
classified as electrical work, in accordance with 6.3.

3.4.3 Energized electrical conductors and circuit parts shall be put into an Electrically
Safe Work Condition by following the process in 6.5 before an employee
performs work if any of the following conditions exist:

a. There is a shock hazard, as determined by a shock hazard analysis in Section 7.1.

b. There is an arc flash hazard, as determined by an arc flash hazard analysis in

Section 8.1.

3.4.4 Exceptions:
a. Normal operation as described in 6.3.5.

b. Switching: Where a disconnecting means or isolating element that has been

properly installed and maintained is operated, opened, closed, removed, or
inserted to achieve an Electrically Safe Work Condition for connected
equipment or to return connected equipment to service that has been placed in
an Electrically Safe Work Condition, the equipment supplying the
disconnecting means or isolating element shall not be required to be placed in
an Electrically Safe Work Condition provided a risk assessment is performed
and does not identify unacceptable risks for the task.
2
 Note: if the arc flash incident energy is greater than 40 cal/cm , the
risk is considered unacceptable unless an engineered remote
switching device can be used (see 8.11).
 c. Additional Hazards or Increased Risk: Energized work shall be permitted
where line management can demonstrate that de-energizing introduces
additional hazards or increased risk. Examples of additional hazards or
increased risk include, but are not limited to, interruption of life-support
equipment, deactivation of emergency alarm systems, and shutdown of
hazardous location ventilation equipment.

d. Infeasibility: Energized work shall be permitted where the line management

can demonstrate that the task to be performed is infeasible in a de-energized
state due to equipment design or operational limitations. Examples of work
that might be performed within the limited approach boundary of exposed
energized electrical conductors or circuit parts because of infeasibility due to
equipment design or operational limitations include performing diagnostics
and testing (for example, start-up or troubleshooting) of electric circuits that
can only be performed with the circuit energized and work on circuits that
form an integral part of a continuous process that would otherwise need to be
completely shut down in order to permit work on one circuit or piece of
equipment.

e. Non-hazardous voltage: Energized electrical conductors and circuit parts that

operate at less than the shock thresholds of 2.2.13 shall not be required to be
deenergized where the capacity of the source and any overcurrent protection
between the energy source and the worker are considered and it is determined
that there will be no increased exposure to electrical burns or to explosion due
to electric arcs.

3.5 Mode 1 – Process for Establishing an Electrically Safe Work Condition (LOTO)

3.5.1 An Electrically Safe Work Condition shall be achieved where required by 6.4 by
executing the following process:

a. Determine all possible sources of electrical supply to the specific equipment.

Check applicable up-to- date drawings, diagrams, and identification tags.
b. After properly interrupting the load current, open the disconnecting device(s) for
each source.

c. Wherever possible, visually verify that all contact points of the disconnecting
devices are fully open or that drawout-type circuit breakers are withdrawn to
the fully disconnected position.

d. Apply personal LOTO locks and tags to the isolation(s) in accordance with PUB-
3000, Chapter 18,
Lockout/Tagout Program.

e. Perform Zero Voltage Verification (ZVV) to verify that the circuit parts are
deenergized. Follow the requirements in Section 9.
3.5.2 Where the possibility of stored electrical energy exists, dissipate the stored
energy by grounding the phase conductors or circuit parts with an approved rated
tool designed for the purpose. For high voltage circuits apply temporary personal
protective grounds rated for the available fault duty. Mode 1 work is considered
energized electrical work but exempt from the requirements for an EEWP. If the
Mode 1 process exposes the worker to any hazard, the activity should be covered
by work control procedures, and a hazard analysis should be performed.

3.5.3 When Mode 1 work is performed in the context of a Complex LOTO Procedure
that involves more than just electrical hazards, care shall be taken to appoint a
designated Person In Charge for the electrical portion of the work. The electrical
PIC will conduct the electrical portion of the LOTO Briefing, which will count as
the Job Briefing.

3.5.4 Placing cord and plug equipment into an Electrically Safe Work Condition is not
electrical work and does not require a QEW and does not require a zero voltage
verification, provided that it meets all of the requirements of LOTO Exemption in
PUB-3000, Chapter 18, Lockout/Tagout Program, Work Process C, Cord-and-
Plug Equipment.

3.5.5 Electrical requirements for proper lockout points

a. Where fuses are used, the simple removal of the fuse is an acceptable means of
isolation for lockout. To prevent the fuse from being replaced by others, lock
out access to the fuse holder. Locking away the fuses themselves without
preventing insertion of different fuses is not a sufficient method of control.

b. Fuseholders with exposed energized terminals shall temporarily be placed

in an Electrically Safe Work Condition while removing or replacing the
fuses.

c. Fuseholders with guarded terminals, but where removal of the fuse exposes
energized terminals that can be touched, shall temporarily be placed in an
Electrically Safe Work Condition while removing or replacing the fuses.
d. Where the lockout point requires the disconnection of wires, the requirements
of 10.4.15 shall be followed.

e. Drawout type circuit breakers:

 Circuit breakers fitted with a racking option shall be racked out to the
fully disconnected position, or removed entirely from the cubicle, when
the isolation is used for the purpose of establishing an electrically safe
work condition.
 Either the racking mechanism or the door shall be locked out to
physically prevent re- insertion of the breaker or any other breaker.
 Where a remote racking device is available, it shall be used. See Section
8.12.4.
3.5.6 The process for clearing a LOTO and restoring equipment to normal operation is
considered Mode 1 work until all grounding devices have been removed the
equipment has been verified safe. After that, restoration falls under normal
operation. When performing Temporary Partial Restoration for testing and the
equipment is not placed in a fully safe normal operating condition, electrical
work shall be performed in Mode 2.

3.6 Mode 2 – Energized Diagnostics (Testing & Troubleshooting)

3.6.1 Energized diagnostics are permitted without an Energized Electrical Work Permit
(EEWP) and include testing, troubleshooting, voltage measuring and visual
inspections. While energized diagnostics do not require an EEWP, they still
require full application of electrical safe work controls. This includes proper
planning, qualifications, job briefing, PPE, temporary barriers, barricades, and
other suitable controls as necessary.

3.6.2 In Mode 2, measurements, diagnostics, testing, and visual inspection of

equipment functions are conducted with the equipment energized and with
some, or all, of the normal protective barriers removed and interlocks bypassed.
Note that Zero Voltage Verification (ZVV) Verification is covered by the Mode
1 process and is not considered Mode 2.

3.6.3 Mode 2 work is considered energized electrical work but exempt from the
requirements for an EEWP. If the Mode 2 process exposes the worker to any
hazard, the activity should be covered by work control procedures, and a hazard
analysis should be performed.

3.6.4 If any portion of the worker’s body passes the Restricted Approach Boundary,
appropriate shock PPE should be worn. If any portion of the worker’s body
passes the Arc Flash Boundary, the appropriate arc flash PPE should be worn.

3.6.5 Manipulation of insulated wires for inspection

a. Insulated wires inside panels may need to be manipulated for inspection of

 wire numbers, sizes, or circuit tracing. This can be performed in Mode 2.

b. All PPE for shock and arc flash protection must be worn.

c. This is not considered visual inspection.

3.6.6 Limited diagnostics are permitted under the QEW skill of the craft subject to the
limitations in 6.10. Complex diagnostics may require additional planning, an
Electrical Safe Work Procedure (6.8), direct field supervision (6.11), or a
combination of controls as necessary for the complexity of the diagnostics and
the degree of hazard involved.

3.6.7 All diagnostic work requires a designated Person In Charge and a Job Briefing.

3.6.8 Visual Inspections

a. Visual inspection of normally-enclosed, exposed energized facilities

distribution equipment greater than 750 VAC (Class 1.4) is prohibited.

b. Other energized electrical equipment may be visually inspected without

placing it in an Electrically Safe Work Condition under the following
conditions:
 Cover panels are hinged or can be removed without risking
breaking the plane of the opening.
 The equipment does not show evidence of impending failure (10.4.10 and
10.4.11).
 Only Qualified Electrical Workers, and persons escorted by a Qualified
Electrical Worker, are authorized to perform the visual inspection.
 The worker must wear the appropriate minimum PPE per Section 10.1. If
inside the arc flash boundary, this must be a QEW 2 wearing the
appropriate arc flash PPE.
 No part of any tool or body may enter the Restricted Approach Boundary.
 The worker must position his/her body in such a way as to preclude
inadvertent movement that would break the Restricted Approach
Boundary.

3.6.9 Infrared Inspections

a. Infrared scans are performed with equipment and/or systems in an

energized state due to load current requirements.
b. During an infrared scan no person will break the Restricted Approach
Boundary of the electrical equipment that has the doors open or covers
removed.

c. Infrared inspections on energized low-voltage equipment shall follow the

requirements of Visual Inspection in 6.6.8.

d. Infrared inspections on energized high-voltage equipment shall require using

permanently installed infrared inspection ports.

e. Performing infrared inspections may create an arc flash hazard (see 8.2.5.e).
3.6.10 Subcontractor Energized Electrical Testing Permit (EETP)

a. Where Required: When subcontractor QEWs perform testing or

troubleshooting on exposed energized electrical conductors or circuit parts
that are not placed in an Electrically Safe Work Condition work.

b. Exceptions:
 Where the equipment is labeled with the arc flash and shock hazards, and
the testing or troubleshooting is performed within the skill of the craft of
the Subcontractor QEW, an EETP shall not be required.
 Where a Subcontractor LOTO Permit already specifies all the relevant
hazards and controls, an additional EETP shall not be required.

c. Elements of the EETP: The energized electrical testing permit shall include, but
not be limited to, the following items:
 An Electrical Safe Work Procedure (see section 6.8) approved by the
EHS Electrical Safety Group
 Verification that the Subcontractors are current in their QEW certification.

d. Approval: The EHS Electrical Safety Group is the final approver for the EETP.

e. Documented Job Briefing:

 All persons participating in the EETP job briefing shall sign in to the EETP.
 The completed EETP, Electrical Safe Work Procedure, and job briefing
sign-in sheet shall be returned to the Electrical AHJ for Safe Work
Practices for record keeping.

f. Application for an EETP: Contact the Electrical Safety Group to apply for an
EETP.

3.6.11 Other controls

a. A standby person or safety watch is required for Mode 2 work (6.13).

 Exception: Visual or infrared inspection of Class 1.2a or 1.2b
equipment does not require a standby person.
b. Alerting techniques are required for Mode 2 work. This includes temporary
barricades and signage using the DANGER signal word. Attendants may be
necessary depending on the situation (10.3).
 Exception: Visual or infrared inspection of Class 1.2a or 1.2b
equipment does not require alerting techniques.
3.7 Mode 3 – Energized Repair Work (EEWP)

3.7.1 Energized electrical work that does not meet the requirements for Normal
Operation, Switching, Placing the equipment in an Electrically Safe Work
Condition, or Energized Diagnostics shall be classified as Electrical Repair Work
and shall be performed in an Electrically Safe Work Condition unless it meets one
of the exemptions in 6.4.4.

3.7.2 When performing Electrical Repair Work on energized electrical conductors or

circuit parts that are not placed in an Electrically Safe Work Condition (i.e., for
the reasons of increased or additional hazards or infeasibility per 6.4.4), work to
be performed shall be considered Energized Electrical Repair Work and shall
require an approved Energized Electrical Work Permit (EEWP).

3.7.3 Elements of the EEWP. The energized electrical work permit shall include, but
not be limited to, the following items:

a. An Electrical Safe Work Procedure (see section 6.8) approved by the EHS
Electrical AHJ for Safe Work Practices

b. Justification for why the work must be performed in an energized condition

c. Energized work approval by a senior line manager designated by the EHS

Electrical AHJ for Safe Work Practices.

3.7.4 Justification:

a. The justification for the EEWP is one of the critical elements of an EEWP.
The EEWP requester must provide sufficient information to substantiate the
request. Energized repair, modification or installation is a high-risk activity
that is most often avoided with proper planning and coordination.

b. Justification shall be based on the increased or additional hazards

clause of 6.4.4.c or the infeasibility clause of 6.4.4.d, or both.
 c. Additionally, justification for the following shall also be provided in the EEWP
application:
 Reason why the work must be performed and no alternatives have been
found adequate, including not doing the work at all.
 Reason why the work cannot be delayed until the next scheduled or
unscheduled outage.

3.7.5 Approval:

a. The EHS Electrical AHJ for Safe Work Practices is not the final approver for
the EEWP. Only a senior line manager who has the authority to require an
outage instead of energized work is authorized to approve an EEWP.

b. After consideration of the scope of work and the justification statement, the EHS
Electrical AHJ for
 Safe Work Practices will select the appropriate senior line managers for
approval of the EEWP. In most cases this will be a division director (or their
deputy) for the division most impacted by the outage. In some cases the EHS
Electrical AHJ for Safe Work Practices will refer the EEWP to the Chief
Operating Officer (COO) for final approval.

3.7.6 Documented Job Briefing:

a. The job briefing for the EEWP shall be documented. All persons
participating in the EEWP job briefing shall sign in to the EEWP.

b. The completed EEWP, Electrical Safe Work Procedure, and job briefing
sign-in sheet shall be returned to the Electrical AHJ for Safe Work
Practices for record keeping.

3.7.7 Application for an EEWP: Contact the Electrical AHJ for Safe Work Practices to
apply for an EEWP. Note that as a matter of policy, the AHJ will normally reject
all applications for an EEWP unless the justification is fully substantiated.

3.7.8 Other controls

a. A safety watch is required for Mode 3 work. See 6.13 for more information.

b. Alerting techniques are required for Mode 3 work. This includes temporary
barricades and signage using the DANGER signal word. Attendants may be
necessary depending on the situation. See 10.3 for more information.

3.8 Electrical Safe Work Procedure (ESWP)

3.8.1 An Electrical Safe Work Procedure is a documented, step-by-step procedure

for executing a specific task or set of tasks on electrical equipment.

3.8.2 An Electrical Safe Work Procedure is the interface between the “planning” and
the “doing.” It is designed to provide an awareness of both electrical hazards
and discipline for all personnel who are required to work in an energized
 electrical environment. A procedure on safe practices on or near electrical
conductors allows for an instant audit of what is required to perform work on
or near energized electrical conductors and circuit parts.

3.8.3 Procedural compliance.

a. Procedures shall be executed as written and approved. No shortcuts or spur-of-

the-moment activity shall be permitted.

b. Work on or near energized conductors and circuit parts that develops, and
which has not been previously identified by a procedure, should be reviewed,
and a special procedure should be written prior to the performance of the work.
 c. When a procedure cannot be safely followed, because the qualified electrical
worker feels there is information missing, an incorrect step, this will be a stop
work condition. Work will not proceed until guidance has been received and the
problem resolved to each person’s satisfaction.

d. Field changes to the Electrical Safe Work Procedure are permissible after
review by an Electrical Safety Officer.

3.8.4 An Electrical Safe Work Procedure may be required for any mode of electrical work.

3.8.5 An Electrical Safe Work Procedure is recommended for all jobs where the
complexity of the task exceeds the normal skill of the craft for the Qualified
Electrical Worker, or where a significant level of coordination is required
between multiple individuals. An Electrical Safe Work Procedure shall be
required for the following types of activities:

a. Any activity requiring an Energized Electrical Work Permit (EEWP)

b. Switching of high voltage distribution equipment (Switching Tags are a form of

ESWP)

c. All activities performed on equipment where arc flash incident energy at

the typical working distance is calculated at >40 cal/cm2, before other
controls are applied

d. Activities performed less than once per year, unless performed under direct field
supervision (6.11)

e. Any activity as deemed necessary by the work lead or an Electrical Safety Officer

3.8.6 The Electrical Safe Work Procedure shall be prepared by one or more QEWs
who are familiar with a given facility or plant.

3.8.7 The Electrical Safe Work Procedure shall be reviewed and approved by an Electrical
Safety Officer.
3.8.8 Elements of the Electrical Safe Work Procedure:

a. Title. The title identifies the specific equipment where the procedure applies.

b. Purpose. The purpose is to identify the job to be performed.

c. Qualification. The training and knowledge that qualified personal shall

possess in order to perform particular tasks are identified.

d. Supervision. The level of direct field supervision (6.11), and the training
and knowledge that supervisor shall possess in order to supervise the
execution of the ESWP.

e. Emergency response plan. Identification of how and where to call for

help, emergency egress, emergency lighting, AED, insulated rescue hook,
location of nearest electrical disconnect, etc.

f. Hazard identification. The hazards that were identified during development of the
procedure are
 highlighted. These are the hazards that may not appear obvious to personnel
performing work on or near the energized equipment.

g. Hazard classification. Results of the shock hazard analysis and arc flash
hazard analysis. The degree of risk, as defined by the hazard analysis, is
identified for the particular job to be performed.

h. Limits of approach. The approach distances and restrictions are identified

for personnel access around energized electrical equipment. Specify
requirement for attendants and/or barricades.

i. Safe work practices. The controls that shall be in place prior to, and during the
performance of, work on or near energized equipment are emphasized.

j. Personnel protective clothing and equipment. The minimum types and

amounts of protective clothing and equipment that are required by personnel to
perform the tasks described in the procedures are listed. Personnel performing
the work shall wear the protective clothing at all times while performing the
tasks identified in the procedure.

k. Test equipment and tools. All the test equipment and tools that are required to
perform the work described in this procedure are listed. The test equipment
and tools shall be maintained and operated in accordance with the
manufacturer’s instructions.

l. Reference data. The reference material used in the development of the

procedure is listed. It includes the appropriate electrical single-line
diagrams, equipment rating (voltage level), and manufacturer’s operating
instructions.

m. Procedure steps. The steps required by qualified personnel wearing personal

protective clothing and using the approved test equipment to perform specific
tasks in a specified manner are identified.
 n. Sketches/drawings. Sketches or drawings are used, where necessary, to
properly illustrate and elaborate specific tasks.

3.8.9 Documented Job Briefing:

a. All persons participating in the Electrical Safe Work Procedure shall sign in to the
job briefing.

b. The completed Electrical Safe Work Procedure and job briefing sign-in sheet
shall be retained by the work supervisor for record keeping.
3.9 Person in Charge (PIC)

3.9.1 Every electrical job shall be assigned a Person In Charge (PIC). The PIC shall
be a Qualified Electrical Worker with suitable competence and experience in
the set of tasks to be performed.

3.9.2 The PIC is responsible for the safe execution of the work.

3.9.3 The PIC shall ensure that:

a. For skill of the craft level tasks, that all persons assigned are suitably
competent, experienced and trained prior to starting work.

b. For specific tasks beyond skill of the craft, that there is an approved Electrical
Safe Work Procedure, or appropriate direct field supervision (6.11), or both.

c. When a question arises that cannot be resolved in the field with the personnel
present, the PIC shall place the equipment in a safe state, pause the work (hold
point) and seek additional assistance. The PIC shall not resume work until the
questions have been satisfactorily resolved.

3.10 QEW Skill of the Craft

3.10.1 Skill of the craft is defined as the set of tasks for which a Qualified Electrical
Worker is fully competent and can perform without additional planning support
or supervision. These vary depending on the individual’s experience, position
description and routine daily work assignments.

3.10.2 When performing skill of the craft level work, all Qualified Electrical Workers
shall be able to determine the degree and extent of the hazard, and the PPE and
job planning necessary to perform the task safely.

3.10.3 Where two or more QEWs are performing work under skill of the craft, one shall
be designated as Person in Charge. When working alone, the QEW shall be the
Person In Charge of his or her own work.
3.10.4 Tasks beyond the normal skill of the craft shall require support in the form of
additional planning and/or direct field supervision. A risk assessment should
determine the appropriate level of control. A written work plan may be a
substitute for direct field supervision. Conversely, direct field supervision may
be a substitute for a written work plan. For higher risk jobs, both a written work
plan and direct field supervision may be required.
3.10.5 Specific training is required for new equipment or when the QEW is not familiar
or experienced with the construction and operation of specific electrical
equipment or installation methods. Line management is responsible for ensuring
that training or extra instruction is made available prior to performing work.
QEWs are responsible for identifying when they do not have the required
knowledge or skill related to specific equipment, and for seeking out training or
extra instruction prior to performing work.

3.11 Direct Field Supervision

3.11.1 Direct field supervision means that a designated competent QEW is present on
site and is providing oversight, guidance and instruction on a specific task or
set of tasks to another person.

3.11.2 Depending on the level of risk, direct field supervision can be performed by a
designated QEW, a QEW Work Lead, a QEW Supervisor, an Electrical Engineer
or an Electrical Safety Officer. In all cases, the designated QEW providing direct
field supervision shall be suitably competent for the set of tasks.

3.11.3 Where an ESWP is required, the level of direct field supervision shall be specified in
the ESWP.

3.11.4 The degree of oversight depends on the level of risk. The following are
examples, as each case will depend on multiple risk factors:

a. For Mode 0 work, it may be sufficient for the QEW providing oversight to
give instructions before the work, check in periodically during the work, and
perform a final inspection upon completion of the work.

b. For other modes, direct field supervision needs to be continuous and at the job site.

c. Where a QEW is providing oversight for an apprentice (or equivalent)

performing Mode 1, 2 or 3 work, the QEW shall remain within arm’s reach
and capable of immediately and physically stopping an unsafe act, such as
touching a potentially energized circuit part before completing the ZVV
process.
3.12 Job Briefing

3.12.1 A job briefing is a verbal communication of the job plan to employees

involved with the job. A job briefing is required for EVERY JOB.

3.12.2 The job briefing is conducted by the designated Person in Charge (PIC) of
the work. The PIC shall conduct the job briefing with the involved
employees before the start of each job.

3.12.3 The job briefing shall be documented with a sign-in sheet for all work requiring
an Electrical Safe Work Procedure. The completed sign-in sheet shall be saved
for record keeping.

3.12.4 The job briefing shall at a minimum, cover the following subjects:

a. Detailed scope of work,

b. hazards associated with the job,

c. work procedures involved,

d. special precautions,

e. energy source controls,

f. two-person rule, and

g. PPE requirements.

3.12.5 If the work or operations to be performed during the workday are repetitive and
similar, at least one job briefing shall be conducted before the start of the first
job of each day or shift. Additional job briefings shall be held if significant
changes, which might affect the safety of the employees, occur during the
course of the work.

3.12.6 A brief discussion is satisfactory if the work involved is routine, and if the
 employee, by virtue of training and experience, can reasonably be expected to
recognize and avoid the hazards involved in the job. A more extensive discussion
shall be conducted if the work is complicated or extremely hazardous, or if the
employee cannot be expected to recognize and avoid the hazards involved in the
job.

3.13 Working Alone or Accompanied

3.13.1 In accordance with the Berkeley Lab Working Alone Policy, workers at Berkeley
Lab are not allowed to work alone when the mitigated hazards associated with
their work could incapacitate them such that that they could not "self-rescue" or
activate emergency services. This includes when an individual may receive
severe electrical shock or arc flash injury.

a. Working alone is defined as when a worker performs electrical work out of sight
and earshot of
 anyone who can help in the event of an emergency.

b. Working accompanied is defined as when a worker performs work with a

Standby Person or a Safety Watch. If either the Standby Person or the Safety
Watch has to leave the area, the activity is considered to be Working Alone,
and must terminate if prohibited in the work authorization.

3.13.2 Working Alone. Typically, the following types of work are allowed to be
performed alone, as the risk of shock or arc flash is considered to be negligible:

a. Normal operation

b. Switching, unless Facilities Distribution High Voltage (>750 VAC) Switching

(Class 1.4)

c. Work performed in an Electrically Safe Work Condition (Mode 0)

d. Placing electrical equipment in an Electrically Safe Work Condition

(Mode 1) when the hazard classification is Yellow (Class X.2) or lower

3.13.3 Standby Person

a. A Standby Person is a second person designated to fulfill the requirements of

working accompanied when a QEW is performing certain types of high hazard
electrical work. While the primary purpose of the second person is to initiate
the emergency response system, a Standby Person is also expected to know
how to deenergize electrical equipment and to safely release a QEW from
contact with energized parts. This triggers additional controls and training.

b. Both the Standby Person and the QEW performing work for which a Standby
Person is required may perform separate jobs or tasks so long as safety is not
compromised.

c. For Facilities High Voltage Distribution (>750 VAC) work, the Standby
Person must also be a QEW 3 (or a QEW 2 who has completed QEW 3 safety
 training). For other work, a Standby Person may be a non-QEW provided that
the emergency disconnect can be operated as non-hazardous switching.

d. A non-QEW performing the role of a Standby Person shall complete and

remain current in the training requirements for Standby Persons set in the
Electrical Safety Program, Work Process J, Electrical Safety Training for
Non-QEWs. These include:
 EHS0116 First Aid
 EHS0123 CPR/AED
 EHS0260 Electrical Safety for Non-QEW Lab Personnel
 EHS0536 Electrical Switching for non-QEWs
 EHS0537 Electrical Injuries and Emergency Response
e. A Standby Person is required when work is considered high hazard electrical
work, as established by the conditions (hazard class and mode of work) in
Tables 3.3 - 3.8, by the Electrical Safe Work Procedure or by the work
supervisor:
 Normal operation: not required
 Switching: requires a Standby Person for Facilities Distribution High
Voltage (>750 VAC) Switching (Hazard Class 1.4).
 Mode 0: not required
 Mode 1: requires a Standby Person when the hazard classification is Red
(Hazard Class X.3) or higher.
 Mode 2: requires a Standby Person when the hazard classification is
Yellow (Hazard Class X.2) or higher. Exception - Mode 2 in Hazard
Class 1.2 may be performed alone, if proper voltage rated gloves and
leather protectors are worn.
 Mode 3: must always be a Safety Watch (6.13.4).

f. Briefing. The standby person must be briefed in emergency procedures and the
electrical work being performed. During the briefing process, the QEW will
assess the qualifications of the standby person to determine that the work may
proceed safely.

g. The Standby Person must:

 If a non-QEW, remain outside of the limited approach boundary or the
arc flash boundary except to initiate a rescue attempt.
 Be aware of the QEW’s tasks. Remain in visual and audible
contact with the QEWs performing the work.
 Be able to deenergize equipment. The electrical disconnecting means
must be located outside of the limited approach boundary and the arc
flash boundary. If it would take more than 1 minute to reach the
designated electrical disconnect, then an acceptable means (such as an
insulated rescue hook or rubber insulated gloves) shall be selected and
prepared to rescue the QEW without first disconnecting power.
 Know the location of nearest telephone, and how to alert emergency rescue
personnel.
  Know the location of the nearest AED.
 Know how to free an injured worker from the hazard.

h. When two or more QEWs are working together, a separate Standby Person is
not required. All QEWs shall be prepared to fulfill the duties of Standby Person
for each other.

i. In the event of an electrical incident, the Standby Person shall initiate the
emergency response in accordance with the Electrical Safety Program, Work
Process K.
3.13.4 Electrical Safety Watch

a. A Safety Watch is a more stringent hazard control measure than the Standby
Person and must be implemented when there are grave consequences from a
failure to follow safe work procedures.

b. A Safety Watch is required when work is considered very high hazard

electrical work, as established by the conditions (hazard class and mode of
work) in Tables 3.3 - 3.8, by the Electrical Safe Work Procedure or by the
work supervisor.
 Normal operation: not required
 Switching: not required
 Mode 0: not required
 Mode 1: not required
 Mode 2: requires a Safety Watch when the hazard classification is Red
(Hazard Class X.3) or higher.
 Mode 3: requires a Safety Watch when the hazard classification is
Yellow (Hazard Class X.2) or higher.

c. The Safety Watch must be a Qualified Electrical Worker of the same level as
that required for the QEWs performing the work, and shall be responsible for
monitoring the Qualified Electrical Worker(s) doing the work.

d. Duties of the Safety Watch include:

 Remain outside of the limited approach boundary or the arc flash
boundary except to initiate a rescue attempt.
 Have a thorough knowledge of the specific working procedures to be
followed and the work to be done.
 Know the location of nearest telephones, and how to alert emergency rescue
personnel
 Know the location of the nearest AED. For Mode 3 work under an EEWP,
have an AED at the job location but outside of the limited approach
boundary or arc flash boundary, whichever is greater.
 Be able to deenergize equipment. The electrical disconnecting means
 must be located outside of the limited approach boundary and the arc
flash boundary. If it would take more than 1 minute to reach the
designated electrical disconnect, then an acceptable means (such as an
insulated rescue hook or rubber insulated gloves) shall be selected and
prepared to rescue the QEW without first disconnecting power.
 At all times, remain in visual and audible contact with the QEWs
performing the work. For critical tasks, remain close enough to the work
in progress to safely monitor the progress and methods of the QEWs
doing the work.
 Closely monitor the progress of the work. Have a copy of the written
work control documents (such as EEWP, ESWP, LOTO Permit,
Switching Tag, etc.) and check or initial tasks
 or steps as necessary. The Safety Watch may call out specific steps and
instructions to the QEWs performing the work, record test
measurements on the procedures.
 Use clothing and PPE appropriate to the hazard and the distance from the
work in progress
 In no case be more than 50 feet from the qualified person(s) performing the
work.
 Ensure only qualified persons are allowed to enter the limited approach
boundary.
 Ensure that the limited approach boundaries are properly barricaded and
controlled.
 Have no other duties that preclude continually observing, coaching,
and monitoring for potential hazards and mistakes.

e. If signs and barricades do not provide sufficient warning and protection for
the limited approach boundary, one or more attendants shall also be
stationed as necessary to warn and prevent non- QEWs from entering (see
10.3).
4 Shock Protection

4.1 Performing a Shock Hazard Analysis

4.1.1 The purpose of a shock hazard analysis is to determine shock hazards and
appropriate safety controls to prevent a shock.

4.1.2 A shock hazard analysis shall determine whether parts are exposed, the voltage to
which personnel will be exposed, the shock protection boundary requirements,
and the personal protective equipment necessary in order to minimize the
possibility of electric shock to personnel.

4.1.3 Where special body positioning techniques are required to prevent shock in the
completion of tasks, these shall be listed. However, consideration shall first be
given to improve barriers, barricades and other precautionary techniques
instead of relying solely on body positioning.

4.1.4 A shock hazard analysis shall be completed prior to performing any work within
the Limited Approach Boundary of exposed electrical conductors or circuit parts
that are or might become energized.

4.1.5 Results of the shock hazard analysis shall be integrated with the arc flash
hazard analysis results as appropriate, and documented into the Electrical Safe
Work Procedure as required.

4.1.6 Steps in performing a shock hazard analysis:

a. Determine whether there is a shock exposure created by the scope of work.

b. Determine the voltage of energized conductors or circuit parts that will be exposed
during the work.

c. Determine the shock protection boundaries associated with the shock hazards.

d. Determine the shock protection PPE: accounting for body position during the
various phases of the work, determine an appropriate combination of rubber
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 insulating gloves and insulating barriers for all work within the Restricted
Approach Boundary.

4.2 Determination of a Shock Hazard

4.2.1 A shock hazard exists when an energized electrical conductor or circuit part is
exposed.

4.2.2 Energized electrical conductors and circuit parts are considered exposed if
capable of being inadvertently touched or approached nearer than a safe
distance by a person, by not being enclosed, guarded or insulated.

a. A part is considered suitably enclosed when it is surrounded by a case, housing,

fence, or wall(s) that prevents persons from accidentally contacting the part.

Page 111 of 217

 b. A part is considered suitably guarded when it is covered, shielded, fenced,
enclosed, or otherwise protected by means of suitable covers, casings, barriers,
rails, screens, mats, or platforms to remove the likelihood of approach or
contact by persons or objects to a point of danger.

c. A part is considered suitably insulated when it is separated from other

conducting surfaces by a dielectric (including air space) offering a high
resistance to the passage of current.

4.2.3 Finger-safe designs.

a. Finger safe designs eliminate the likelihood of inadvertent or accidental contact

with bare hands and fingers.

b. Finger safe design requirements are set by IEC 60529, Degrees of Protection
Provided By Enclosures (IP Code). Equipment is normally not labelled for
finger safe design. A field evaluation of finger safe design compliance can be
made by a QEW using an Articulated Test Finger (Fig. 7.2.3). Either the UL or
the IEC test fingers may be used and can be borrowed from the Electrical
Safety Group. The panel must first be placed in an Electrically Safe Work
Condition.

c. The two designations for finger safe ratings are IP2X and IPXB, where X is a
placeholder for another rating, such as water resistance or dust resistance.
Both are equivalent as far as the fingers are concerned.

d. When performing a shock hazard analysis, finger safe parts are not considered
exposed even when energized, so long as the QEW is only interacting with the
hands.

e. Finger safe parts shall be considered exposed in any of the following conditions:
 The QEW is handling conductive tools or parts, such as loose wires,
wire harnesses, screws, bolts, or circuit boards.
 Any non-QEW is escorted within the Limited Approach Boundary.

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 f. Non-QEWs are not trained to recognize hazardous conditions in electrical
panels, and are not expected to be able to determine whether parts are finger
safe or not. Non-QEWs may be authorized to work inside finger safe live
panels provided they receive a job briefing from a QEW detailing the shock
hazard posed by the live components.

4.2.4 Temporary barriers.

a. Temporary barriers may be placed over exposed parts. When these are in
place, the exposure is eliminated.

b. When placing barriers for non-QEWs and QEWs alike, the barriers shall be
sufficient to:
 Insulate against the voltage hazard
 Remain securely in place for the duration of work

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  Prevent inadvertent contact by bare hands and fingers, when using insulated
tools
 Prevent inadvertent contact by conductive tools and parts if necessary

Fig. 7.2.3 – Articulated Test Fingers. IEC at the top, UL at the bottom.

4.3 Shock Protection Boundaries

4.3.1 Shock protection boundaries are defined based on equipment voltage alone and
are illustrated in Figure 7.3 and listed in Tables 7.3.AC and 7.3.DC. Shock
protection boundaries are not defined unless an energized conductor is exposed
(7.2). There are three shock protection boundaries:
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a. Limited Approach Boundary

b. Restricted Approach Boundary

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 c. Prohibited Approach Boundary

4.3.2 Limited Approach Boundary

a. The Limited Approach Boundary is the closest distance that a non-QEW

can approach exposed energized conductors without escort.

b. For AC equipment <750 VAC, the Limited Approach Boundary of 42 inches is

based on the depth of the required working space in Condition 2 (5.12.9). This
in turn is based on the standard human arm length of 3 feet, plus 6 inches of
lean. The idea is that non-QEWs looking over the shoulder of a QEW are very
likely to want to point at the equipment and may inadvertently make contact
with exposed parts.

c. A non-QEW may be escorted within the Limited Approach Boundary by a

Qualified Electrical Worker, but may never enter the Restricted Approach
Boundary. Where there is a need for a non- QEW to cross the limited approach
boundary, a QEW shall advise him or her of the possible hazards and
continuously escort the non-QEW while inside the limited approach boundary.
Under no circumstance shall the escorted non-QEW be permitted to cross the
restricted approach boundary.

d. Where one or more non-QEWs are working at or close to (but outside of) the
limited approach boundary, the designated person in charge (PIC) of the work
space where the electrical hazard exists shall advise the non-QEW of the
electrical hazard and warn him or her to stay outside of the limited approach
boundary.

e. The Limited Approach Boundary is also the trigger distance for

implementing an Electrically Safe Work Condition (see 6.4). Note that this
applies even though shock protection boundaries are defined when the
equipment is not in an Electrically Safe Work Condition. Following the
LOTO Program requirements, each individual must apply their personal
LOTO lock(s) prior to working within the Limited Approach Boundary.
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 f. All tools that enter the Limited Approach Boundary shall be insulated for the
equipment voltage.

4.3.3 Restricted Approach Boundary

a. Above 300 VAC, the Restricted Approach Boundary is based on adding 12

inches of inadvertent movement to the minimum air flashover distance for
the voltage.

b. Access to the Restricted Approach Boundary shall be restricted to Qualified

Electrical Workers only, and requires an Energized Electrical Work Permit for
Mode 3 work as described in 6.7.1.

c. All parts of the Qualified Electrical Worker’s body that enter the Restricted
Approach Boundary shall be insulated or guarded from the energized electrical
conductors or circuit parts as follows:

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  The Qualified Electrical Worker shall wear rubber insulating gloves
(or rubber insulating gloves and sleeves) to protect the hands (or
hands and arms) from shock. These are considered insulation only
with regard to the energized parts upon which work is being
performed.
 If there is a need for other parts of the Qualified Electrical Worker’s body
to cross the Restricted Approach Boundary to other energized electrical
conductors or circuit parts, those energized electrical conductors or circuit
parts shall be insulated from the Qualified Electrical Worker and from
any other conductive object at a different potential, using a combination
of insulating blankets, insulating sheeting or barriers as determined by
analysis.

4.3.4 Prohibited Approach Boundary

a. Coming closer than the Prohibited Approach Boundary is considered the

same as making contact with energized parts.

b. There are no additional requirements at Berkeley Lab for entering the

Prohibited Approach Boundary6, as an EEWP is required for entering
the Restricted Approach boundary.

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6 Note: In this Electrical Safety Manual, all NFPA 70E requirements for entering the
Prohibited Approach Boundary are rolled up into the Limited and Restricted Approach
Boundaries.

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Fig. 7.3 – Shock Protection Boundaries for an exposed, energized conductor.

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 Nominal System Limited Approach Boundary Restricted Approach
AC Voltage Boundary
Range, Phase to Exposed Exposed
Phase a Movable Fixed
Conductor Circuit
b
Part
<50 V Not Not Not
specified specified specified
50 V–300 10 ft 3 ft 6 in Avoid
Vc contact
301 V–750 10 ft 3 ft 6 in 12 in
Vd
751 V–15 10 ft 5 ft 2 ft 2 in
kV
15.1 kV–36 kV 10 ft 6 ft 2 ft 7 in
36.1 kV–46 kV 10 ft 8 ft 2 ft 9 in
46.1 kV–72.5 10 ft 8 ft 3 ft 3 in
kV
72.6 kV–121 10 ft 8 in 8 ft 3 ft 4 in
kV
>121 kV Contact the Electrical Safety Group
for direction
Note: All dimensions are distance from exposed energized electrical conductors or circuit
parts to worker.
a. For single-phase systems, select the range that is equal to the system’s maximum
phase-to-ground voltage multiplied by 1.732.
b. Exposed movable conductor describes a condition in which the distance between the
conductor and a person is not under the control of the person. The term is normally
applied to overhead line conductors supported by poles.
c. Does not include 277 V single phase, as this is not the phase to phase voltage.
d. Includes 277 V single phase, as the phase to phase voltage is 480 V.
Table 7.3.AC – Shock Protection Boundaries for AC Systems

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 Nominal Limited Approach Boundary Restricted Approach
DC Boundary
Exposed Exposed Fixed
Potential Circuit Part
Differen Movable
ce Conductor
a

<100 V Not Not specified Not

specified specified
100 V–300 10 ft 3 ft 6 Avoid
V in contact
301 V–1 kV 10 ft 3 ft 6 12 in
in
1.1 kV–5 10 ft 5 ft 1 ft 5 in
kV
5.1 kV–15 10 ft 5 ft 2 ft 2 in
kV
15.1 kV–45 10 ft 8 ft 2 ft 9 in
kV
45.1 kV– 75 10 ft 8 ft 3 ft 2 in
kV
75.1 kV–150 10 ft 8 in 10 ft 4 ft 0 in
kV
150.1 kV–250 11 ft 8 in 11 ft 8 in 5 ft 3 in
kV
250.1 kV–500 20 ft 0 in 20 ft 0 in 11 ft 6 in
kV
500.1 kV–800 26 ft 0 in 26 ft 0 in 16 ft 5 in
kV
Note: All dimensions are distance from exposed energized electrical conductors or circuit
parts to worker.
a. Exposed movable conductor describes a condition in which the distance between the
conductor and a person is not under the control of the person. The term is normally
applied to overhead line conductors supported by poles.
Table 7.3.DC – Shock Protection Boundaries for DC Voltage Systems

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4.4 When Voltage Rated Gloves Are Required

4.4.1 Qualified Electrical Workers shall wear rubber insulating gloves with leather
protectors where there is a shock hazard to the hands due to contact with
energized electrical conductors or circuit parts. This includes anytime the hands
enter the Restricted Approach Boundary.

4.4.2 A shock hazard to the hands is considered to exist as follows:

a. For all cases:

 Whenever the task creates an unacceptable risk of accidentally contacting
exposed energized parts. Take into account body positioning and
equipment configuration.
 When manipulating insulated wires that are not jacketed for
physical protection. For example, separating THHN wires in an
MCC to perform a load check with a clamp-on ammeter.

b. For exposures at 50-300V, where the Restricted Approach Boundary is “Avoid

Contact”:
 Any time QEW is required to reach over, across, or near (closer than 3
inches) exposed live parts, unless all exposures are finger safe per 7.2.3.
 When performing a voltage test with a contact voltmeter, unless the
terminals are finger safe per 7.2.3 or using probes with finger guards.

c. For exposures 301-750V:

 Any time the hands enter the Restricted Approach Boundary (12 inches from
the exposure).
 When opening or removing enclosure covers (hinged or bolted).
 When temporarily defeating or bypassing an electrical safety interlock per
10.4.14.

d. For exposures >750 V:

 Any time the hands enter the Restricted Approach Boundary (2 ft 2
inches from the exposure for 12.47 kV). This includes when using an
insulated stick.
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  When manipulating high voltage wires or cables (even if they are jacketed).

4.5 When Leather Protector Gloves Are Required

4.5.1 Leather protector gloves may be omitted under limited use conditions, where
small equipment and parts manipulation require unusually good finger dexterity,
provided the following conditions of ASTM F 496, Standard Specification for In-
Service Care of Insulating Gloves and Sleeves, section 8.7.4 are met:

a. For Class 00 gloves, the rating shall be halved to 250 VAC/375 VDC.

b. For Class 0 gloves, without other restriction.

c. For gloves of Class 1-4, only where the possibility of physical damage to
gloves is unlikely and provided the voltage class of the glove used is one
class above the voltage exposure.

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4.5.2 Rubber insulating gloves that have been used without protectors shall not be used
with protectors until given an inspection and electrical retest. It is recommended
to exchange the gloves for a new set of tested gloves immediately after use
without leather protectors.

4.5.3 Note that “small equipment and parts manipulation” does not include testing with
a meter and usually implies work in Mode 3, which requires an Energized
Electrical Work Permit (EEWP).

4.6 When Voltage Rated Blankets or Sheeting Are Required

4.6.1 QEWs shall apply insulated blankets or insulated sheeting over exposed
parts that could come in contact with the arms or other parts of the body that
are not adequately protected by the use of rubber insulating gloves.

4.6.2 Alternatively, QEWs may also wear rubber insulating sleeves where there is a
danger of arm injury from electric shock due to contact with energized electrical
conductors or circuit parts. Note that blind reaching is prohibited per 10.4.2.

4.7 When Insulated Sticks (Hot Sticks) Are Required

4.7.1 Insulated sticks shall be used for high voltage exposures (> 750 VAC or >
1000 VDC), where the Restricted Approach Boundary exceeds 1 foot.

4.7.2 Insulated sticks shall be used for all tasks within the Restricted Approach Boundary.

4.8 Selection of Shock Protection PPE

4.8.1 Shock protection PPE shall be based primarily on the voltage of the highest
exposure. Rubber insulating gloves, sleeves, and blankets shall be rated according
to the following table:

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 Cla Class Max Use Voltage
ss Color AC/DC
00 Beige 500 VAC / 750
VDC
0 Red 1,000 VAC / 1,500
VDC
1 White 7,500 VAC / 11,250
VDC
2 Yellow 17,000 VAC /
25,500 VDC
3 Green 26,500 VAC /
39,750 VDC
4 Orange 36,000 VAC /
54,000 VDC
Table 7.8.1 – ASTM Classification of Voltage Glove and Blanket Ratings

4.8.2 More information about Shock PPE standards, care, inspection and use can be found
in Section 16.

4.9 Primary vs. Secondary Shock Protection

4.9.1 Primary shock protection is defined as a protective device (rubber insulating

glove, sleeve, blanket, barrier or insulating stick) that, used alone, is fully
sufficient in preventing a shock to personnel that might be exposed.

4.9.2 Secondary shock protection is defined as a supplementary measure, used in

conjunction with a primary shock protection method, to further reduce the risk of
a shock. Some of the PPE available for secondary protection was used for bare-
hand work. Bare-hand work is not authorized.

4.9.3 Secondary shock protection methods include:

a. EH (Electrical Hazard) shoes meeting ASTM F2413 can provide a secondary

source of electric shock protection under dry conditions. EH rated shoes are
regular work shoes with an insulated barrier built into the sole.

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Fig. 7.9.3 – Example of Electrical Hazard (EH) Rated Work Shoes

b. Dielectric floor mats

c. Rubber insulating gloves (above 34 kVAC/54 kVDC)

4.9.4 When working on high voltage systems (>750 VAC), the primary shock
protection device is the insulating stick (hot stick). Rubber insulating gloves and
sleeves may be substituted as primary shock protection up to 34 kVAC/54 kVDC
(Class 4 maximum use voltages) as long as no other part of the body enters the
restricted approach boundary. Above this level there are no rubber insulating
gloves and the insulating stick becomes the sole primary shock protection device.

4.9.5 Primary shock protection devices shall be tested before issue and periodically in
accordance with the requirements in Section 17. Tests for devices used as
secondary protection is recommended but not required.

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8 Arc Flash Protection

8.1 Arc Flash Hazard Analysis

8.1.1 The purpose of an arc flash hazard analysis is to determine whether an arc flash
hazard exists and what appropriate safety controls are necessary to prevent a
second-degree burn.

8.1.2 An arc flash hazard analysis shall be required for all AC systems above the
thresholds of 2.3.3 when planning work under either of the following
conditions:

a. Work within the limited approach boundary of exposed energized electrical

conductors or circuit parts.

b. Work involves interaction with equipment where conductors or circuit parts are
not exposed but an increased likelihood of injury from an exposure to an arc
flash hazard exists.

8.1.3 An arc flash hazard analysis shall not be required for DC systems7.

8.1.4 An arc flash hazard analysis shall determine whether an arc flash hazard exists,
and if so, the arc flash boundary, the incident energy at the working distance,
and the personal protective equipment that people within the arc flash boundary
shall use.

8.1.5 At Berkeley Lab, the arc flash hazard analysis for AC systems shall be
performed using the incident energy analysis method. The “table method” of
NFPA 70E-2012 Article 130.7(C)(15) shall not be used.

8.1.6 Where special body positioning techniques are recommended to stay out of the
line of fire during the performance of tasks, these shall be listed. However,
consideration shall first be given to improve barriers, barricades and other
precautionary techniques instead of relying solely on body positioning.

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8.1.7 Results of the arc flash hazard analysis shall be integrated with the results of the
shock hazard analysis as appropriate, and documented into the Electrical Safe
Work Procedure as required.

8.1.8 Steps in performing an arc flash hazard analysis:

a. Determine whether there is an arc flash hazard exposure created by the scope of
work.

b. Determine the incident energy at the working distance.

c. Determine the arc flash boundary.

7 NFPA 70E-2012 has introduced methods to perform an arc flash hazard analysis for DC
systems. These have not yet been adopted by Berkeley Lab.

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 d. Determine the arc flash PPE, accounting for body position during the various
phases of the work. This may include a combination of arc flash PPE, arc
flash blankets, and barriers for all work within the Arc Flash Boundary.

8.2 Determination of an Arc Flash Hazard

8.2.1 An arc flash hazard is a dangerous condition associated with the possible release
of energy caused by an electric arc, resulting in second-degree burns to the skin
or ignition of clothing.

8.2.2 An arc flash hazard may exist when a person is interacting with the equipment
in such a manner that could cause an electric arc, regardless of whether
energized electrical conductors or circuit parts are exposed. However, under
normal operating conditions, enclosed energized equipment that has been
properly installed and maintained is not likely to pose an arc flash hazard.

8.2.3 The following equipment, when rated at 50-250 VAC, 50-60 Hz power, does
not pose an arc flash hazard, regardless of the activity:

a. Any equipment for which the calculated incident energy at the working
distance is 1.2 cal/cm2 or less.

b. Any equipment that is cord and plug and less than 100 A rated input.

c. Any equipment rated at 120 VAC. This does not include 120 VAC circuit
breakers in a 208 VAC panel with an arc flash hazard.

d. Any equipment rated at 208-240 VAC when at least two overcurrent

protective devices (circuit breakers or fuses) are installed between the
equipment and the closest upstream transformer.

e. Any equipment rated at 208-240 VAC when the closest upstream transformer
is rated at less than 125 kVA.

8.2.4 The following activities do not create an arc flash hazard:

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a. Reading a panel meter while operating a meter switch.

b. Work on control circuits with exposed energized electrical conductors and

circuit parts, 120 VAC or below without any other exposed energized
equipment over 120 VAC. Includes opening of covers to gain access.

c. Insulated cable examination with no manipulation of cable.

d. For DC systems, insertion or removal of individual cells or multi-cell units of

a battery system in an open rack.

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 e. Removal or installation of covers for equipment such as wireways, junction
boxes, and cable trays that does not expose bare energized electrical
conductors and circuit parts.

f. Application of temporary protective grounding equipment after ZVV.

8.2.5 The following activities can create an arc flash hazard when the available
incident energy at the working distance is greater than 1.2 cal/cm2:

a. Work within the Restricted Approach Boundary of energized electrical

conductors and circuit parts greater than 120 VAC, including voltage testing

b. Operation of a circuit breaker, switch, contactor, or starter

 Exception: when conditions for normal operation are satisfied (6.3.5),
the threshold for an arc flash hazard is greater than 4 cal/cm2.

c. Removal of bolted covers to expose bare energized electrical conductors and

circuit parts

d. Opening hinged door(s) or cover(s) to expose bare energized electrical conductors

and circuit parts

e. Visual inspection (including infrared inspection) of exposed bare energized

electrical conductors and circuit parts
 Exception: if doors or covers are removed and replaced while the
equipment is in an electrically safe work condition, and there is a
barricade between the inspector and the equipment that is outside of
the limited approach boundary, then there is no arc flash hazard.

f. Insertion or removal of individual starter buckets from motor control

center (MCC). See requirements of 8.12.

g. Insertion or removal (racking) of circuit breakers or starters from cubicles, doors

open or closed

h. Insertion or removal of plug-in devices into or from busways

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i. Insulated cable examination with manipulation of cable

j. Insertion and removal of revenue meters (kW-hour, at primary voltage and current)

k. Application of temporary voltage and current monitoring sensors or clips

inside panelboards or switchboards

l. Opening voltage transformer or control power transformer compartments

m. Outdoor disconnect switch operation (hookstick operated) at 1 kV through 15 kV

n. Outdoor disconnect switch operation (gang-operated, from grade) at 1 kV through

15 kV

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 o. Application of temporary protective grounding equipment without ZVV

8.2.6 All other activities will be evaluated on a case-by-case basis.

8.3 Incident Energy Analysis

8.3.1 The incident energy analysis is the calculation of arc flash incident energy by
competent engineering persons for a circuit, panel, or system. It is typically
performed by an electrical engineer in conjunction with the short circuit and
protection study.

8.3.2 The incident energy analysis shall be updated when a major modification or
renovation takes place. It shall be reviewed periodically, not to exceed 5 years,
to account for changes in the electrical distribution system that could affect the
results of the arc flash hazard analysis.

8.3.3 The incident energy analysis shall take into consideration the design of the
overcurrent protective device and its opening time, including its condition of
maintenance. Improper or inadequate maintenance can result in increased
opening time of the overcurrent protective device, thus increasing the incident
energy.

8.3.4 The incident energy analysis method shall be used to calculate:

a. The arc flash boundary, and

b. The incident energy at the specified work distance.

8.3.5 The incident energy analysis shall be documented and kept on file.

8.4 Arc Flash Boundary

8.4.1 The arc flash boundary is the distance from an exposed, energized conductor at
which the arc flash incident energy is 1.2 cal/cm2. This is the threshold at which
an arc flash could result in a second-degree burn to the worker, should an arc
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 occur at that conductor. In general, the arc flash boundary is determined by the
available fault current and the time to clear the fault, which determines the energy
deposited into the arc.

8.4.2 The arc flash boundary may be inside or outside the shock approach boundaries.
Figure 8.4.2a shows an arc flash boundary that is outside of the Limited
Approach Boundary, as is typical with many facility circuits, and Fig. 8.4.2b
shows an arc flash boundary that is inside the Prohibited Approach Boundary, as
is common with many high-voltage, low-energy circuits.

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Fig. 8.4.2a Arc flash boundary outside of the limited approach boundary.

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Fig. 8.4.2b Arc flash boundary inside of the prohibited approach boundary.

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8.5 Working Distance

8.5.1 Arc-flash protection is always based on the incident energy level on the person’s
head and torso at the working distance, not the incident energy on the hands or
arms. The degree of injury in a burn depends on the percentage of a person’s skin
that is burned. The head and torso make up a large percentage of total skin surface
area and injury to these areas is much more life threatening than burns on the
extremities.

8.5.2 Care must be taken to note the working distance that is associated with the
calculated incident energy. Where the task requires a working distance that is
closer than the working distance, the incident energy must be recalculated under
engineering supervision. Conversely, tasks that are performed farther than the
indicated working distance may allow a relaxation in the specified PPE and
controls provided that the incident energy is recalculated under engineering
supervision. In either case, the arc flash hazard analysis and controls shall be
documented.

8.6 Incident Energy Analysis for Facility Power Systems

8.6.1 For facility power systems (i.e., Hazard Classes 1.2, 1.3, and 1.4) that are from
200 VAC to 15 kVAC, the incident energy analysis shall be performed by
Facilities Engineering.

a. Equipment rated at <15 kVAC will be evaluated in accordance with IEEE Std
1584, Guide for Performing Arc Flash Hazard Calculations, including 1584a –
Amendment 1 and 1584b – Amendment 2: Changes to Clause 4.

b. Equipment rated at >15 kVAC will be evaluated using ArcPRO.

8.6.2 Typical working distances are shown in Table 8.6.2. These are incorporated
in the incident energy analysis.

Classes of Equipment Typical Working

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 Distance (in)
15 kV switchgear 36
5 kV switchgear 36
Low-voltage switchgear 24
Low-voltage MCC’s and 18
panelboards
Cable 18
Other To be determined in
the field
Table 8.6.2 – Typical working distances for arc flash incident energy calculation

8.6.3 2-second rule:

a. A maximum time exposure cap of 2 seconds is normally applied in the

calculation of incident energy, where the overcurrent protective device does not
trip at the calculated arcing current. This practice

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 is based on an assumption that the worker will likely remove himself or
herself from the arc flash if physically possible, within a maximum time of 2
seconds. See NFPA 70E Annex D.6 or IEEE 1584b- 2011 4.6, Step 5 for more
information.

b. The 2-second rule shall not be applied for any work within electrical manholes,
in vaults, on elevated platforms, or in any other situation where the worker is
unlikely to be physically capable of exiting the arc flash boundary on their own.

c. Workers who are working in spaces where they are unlikely to be physically
capable of exiting the arc flash boundary on their own shall seek EHS support
in performing the arc flash hazard analysis.

8.7 Incident Energy Analysis for R&D Systems

8.7.1 Specialized system knowledge and methods may be necessary to calculate the
incident energy and arc flash boundaries for some non-typical electrical
equipment found in DOE workplaces, such as DC or capacitor systems, as
methods are not available in existing codes and standards. Engineering
supervision should be used to determine whether an arc flash hazard exists.

8.8 Energy Reducing Maintenance Switches

8.8.1 An arc energy reducing maintenance switch allows a worker to set a circuit
breaker trip unit to operate faster while the worker is working within an arc flash
boundary, and then to set the circuit breaker back to a normal setting after the
potentially hazardous work is complete.

8.8.2 Energy reducing maintenance switches have various names depending on the
manufacturer:

a. Arcflash Reduction Maintenance Switch (ARMS) for Eaton gear

b. Reduced Energy Let Through (RELT) for GE gear

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c. Dynamic Arc Flash System (DAS) Parameter Switch for Siemens gear

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8.8.3 Arc energy reducing maintenance switching is usually available on newer
installation Low Voltage Power Circuit Breakers (LVPCB) inside low voltage
switchgear. ARMS functions by temporarily lowering the instantaneous
electronic trip setpoint to its lowest current setting. In doing so, the setting
disables the normal selective coordination with other overcurrent protective
devices in the system. Should a fault happen in the system downstream of the
breaker, there is a risk of wider power outage because the breaker in arc energy
reducing maintenance mode is likely to trip before other devices located
downstream.

8.8.4 Control. When placing the arc energy reducing maintenance switch into
maintenance mode, the switch should be controlled by placing an administrative
lock on the switch cover.

8.8.5 Restoration. After completion of the work that required placing the ARMS in
maintenance mode, the arc energy reducing maintenance switch shall be
restored to normal. Failure to restore the switch to normal could lead to
unnecessary power outages due to lack of proper selective coordination.

8.9 Arc Flash Labeling

8.9.1 Electrical equipment such as switchboards, panelboards, industrial control

panels, meter socket enclosures, motor control centers that are likely to
require examination, adjustment, servicing, or maintenance while energized,
shall be field marked with a label containing all the following information:

a. A warning about the potential for an arc flash, with the word “WARNING”
on an orange colored background

b. Nominal system voltage

c. Available incident energy and the corresponding working distance

d. Arc flash boundary

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e. Date of the arc flash hazard analysis

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8.9.2 Labeling shall conform to the requirements of ANSI Z535.

8.9.3 Labels applied prior to September 30, 2011, are acceptable if they contain the
available incident energy or required level of PPE.

8.9.4 The labeled incident energy shall be that of the highest source, faulting under
the most conservative system lineup, and shall not rely on a protective device
contained within the enclosure.

8.9.5 Where work is planned to take account of a lower incident energy, based on a less
conservative system lineup or the use of an Energy Reduction Maintenance
Switch, the arc flash hazard analysis shall be documented in an Electrical Safe
Work Procedure. LOTO controls shall be used to implement the alternate system
lineup. It is acceptable to post alternate arc flash labels where such controls are
likely to be frequently used, and thereby the Electrical Safe Work Procedure is
not required.

8.9.6 Where the incident energy exceeds 40 cal/cm2 at the standard working distance
of 8.6.2, additional requirements for arc flash labeling are listed in 8.11.4.

8.10 Arc Flash PPE Selection

8.10.1 After determining the incident energy exposure at the working distance, the
worker shall select the appropriate site-specific level of arc flash PPE from
Table 8.10.1.

8.10.2 More information about arc flash PPE standards, care, inspection and use can be
found in 17.5.

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Arc Flash Incident Arc-Rated Gear Other
PPE Energy PPE
Level Range
Daily arc-rated wear for  Safety Glasses
1.2 cal/cm2  Non-melting clothing
Min PPE or less QEW 2 and QEW 3 Crafts,  Non-melting footwear
according to 8.13
(not an arc
flash
(see 10.1) hazard)
Rating: minimum of 4 ATPV  Hard hat
 Safety glasses
1 >1.2  Hearing protection
Arc-rated long-sleeve shirt  Leather work shoes
cal/cm2 
 Heavy-duty leather gloves
to 4.0 and pants (or arc- rated
cal/cm 2 coveralls)
 Arc-rated faceshield
 Arc-rated balaclava
Rating: minimum of 8 ATPV  Hard hat
 Safety glasses
2 >4.0  Hearing protection
Arc-rated long-sleeve shirt  Heavy-duty leather work
cal/cm2 
boots
to 8.0 and pants (or arc- rated  Heavy-duty leather gloves
cal/cm 2 coveralls)
 Arc-rated faceshield
 Arc-rated balaclava
Rating: minimum of 12 ATPV  Hard hat
 Safety glasses
2+ >8 cal/cm2  Hearing protection
Arc-rated long-sleeve shirt  Heavy-duty leather work
to 
boots
12 cal/cm2 and pants (or arc- rated  Arc-rated gloves, or
coveralls) rubber insulating
 Arc-rated faceshield
 Arc-rated balaclava gloves with leather
protectors
Rating: minimum of 25 ATPV  Hard hat
 Safety glasses
3 >12 cal/cm2  Hearing protection
to  Arc-rated flash suit (pants  Heavy-duty leather work
and jacket) boots
25 cal/cm2  Arc-rated flash suit hood  Arc-rated gloves, or
rubber insulating
gloves with leather
protectors
Rating: minimum of 40 ATPV  Hard hat
 Safety glasses
4 >25 cal/cm2  Hearing protection
 Arc-rated flash suit (pants  Heavy-duty leather work
to and jacket) boots
40 cal/cm2  Arc-rated flash suit hood  Arc-rated gloves, or
rubber insulating
gloves with leather
protectors
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Table 8.10.1 – LBNL Site-Specific Arc Flash PPE Levels

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8.11 Arc flash incident energy >40 cal/cm2

8.11.1 Where the incident energy exceeds 40 cal/cm 2, there is an increased risk that the
blast effects will exceed the capacity of the arc flash PPE. Arc-rated gear protects
primarily against the thermal effects of an arc flash, not the blast effects.

8.11.2 Where the incident energy exceeds 40 cal/cm2 at the standard working distance
of 8.6.2, additional controls shall be implemented to reduce the exposure.
These include but are not limited to:

a. Placement of the ARMS switch in maintenance mode to reduce the incident

energy at the working distance.

b. Use of an alternate system lineup to eliminate high energy contributors to the

system. For example, lock out an emergency generator.

c. Using engineered remote switching devices to extend the working distance. If

possible, extend the distance outside of the calculated arc flash boundary.
Otherwise, request engineering assistance to recalculate the distance at which
the arc flash energy is reduced to 40 cal/cm 2, or calculate the incident energy
at another feasible working distance.

d. Unless specific controls are labeled on the equipment, these alternative

measures shall be documented in an approved Electrical Safe Work
Procedure.

8.11.3 Where none of the methods identified in 8.11.2 are achievable, consult with the
Electrical AHJ for Safe Work Practices.

8.11.4 Arc flash labeling for conditions where the incident energy exceeds 40 cal/cm 2 at
the standard working distance shall conform to 8.9 but shall additionally be
modified as follows:

a. The label shall state DANGER instead of WARNING, on a background colored

red instead of orange.
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b. The label shall also include the working distance at which the incident energy
equals 40 cal/cm2.

c. The label shall include the following statement: “The available arc flash
incident energy in this panel is considered to be extremely dangerous. Consult
with the Electrical Safety Group to develop the necessary safe work procedure
prior to performing any work on this panel, including switching and LOTO.”

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8.12 MCC Buckets, Busway Plug-In Units and Drawout Type Circuit Breakers

8.12.1 Energized removal and insertion of MCC buckets or busway plug-in units present
a high probability of an arc flash when compared to other activities, especially on
older equipment or equipment that has not been well maintained. Because there is
no remote racking option available, the QEW is in very close proximity to the
source of energy and often has to exert physical effort in the task.

8.12.2 Only a QEW may remove or insert an MCC bucket or busway plug-in unit.

8.12.3 Where the incident energy available in the MCC or busway is calculated at
greater than 12 cal/cm2, energized removal and insertion shall only be
performed under an approved EEWP.

8.12.4 Drawout type circuit breakers present a similar risk, although a remote racking
option is usually available. The remote racking mechanism shall be used where
available. Where a remote racking mechanism is not available and the incident
energy available in the switchgear is calculated at greater than 12 cal/cm2,
racking of drawout type circuit breakers shall only be performed under an
approved EEWP.

8.13 Daily Arc-Rated Work Wear for Electrical Work

8.13.1 The purpose of the daily arc-rated work wear requirement is to protect electrical
workers from injuries sustained when the equipment is thought to be in an
Electrically Safe Work Condition (Mode 0). Many injuries occur after LOTO or
Test Before Touch have been incorrectly performed. The daily arc-rated work
wear will not fully protect the worker, but can significantly reduce the likelihood
of a life-altering burn injury.

8.13.2 Daily arc-rated work wear shall be required for all craft QEWs levels 2-3
and their immediate supervisors, if the supervisors are also QEWs.

8.13.3 Daily arc-rated work wear by QEW classification:

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a. QEW 1: No requirement (see minimum PPE requirement in 10.1)

b. QEW 2: Minimum of arc-rated pants and long-sleeve shirt (or equivalent

combination), rated at least 4 cal/cm2, with non-melting undergarments.

c. QEW 3: Minimum of arc-rated pants and long-sleeve shirt (or equivalent

combination), rated at least 4 cal/cm2, with non-melting undergarments. Note
that arc-rated undergarments are recommended for high voltage work because
of the possibility of a tracking arc under the arc-rated PPE.

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8.13.4 QEWs assigned to wear daily arc-rated work wear shall also be furnished with
arc-rated safety vests and cold weather apparel where necessary.

8.14 Body Positioning for Arc Flash

8.14.1 Arc flash calculations are roughly based on spherical expansion, with the
incident energy decreasing proportionally to the square of distance. This is
especially accurate for an arc in open air.

8.14.2 For arc in a box, the calculation is modified twice. First, to account for the gain
of reflecting all the energy in one direction. Second, to give different exponent
factors (other than square) to account for the varying focusing effect of different
switchgear. For example, larger switchgear tends to approximate a planar
source, while a MCC bucket tend to approximate a point source.

8.14.3 However, arc flash calculations do not yet account for convective plasma flow
patterns commonly observed in real world arc flash events. Convective flow can
lead to very high concentration of the available energy that exceeds the calculated
incident energy at the working distance and can possibly exceed the arc rating of
the PPE ensemble. Proper body positioning can help the worker avoid standing
with part of the body in the line of fire (2.3.3.b and 10.2.7).

8.14.4 Proper switching technique in 10.2.7 incorporates proper body positioning for arc
flash.

8.14.5 For other cases, see 10.2.8.

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9 Zero Voltage Verification (ZVV)

9.1 Purpose

9.1.1 Zero Voltage Verification (ZVV) is the practice of testing for the absence of
hazardous voltage on circuits that have been or are being placed in an
Electrically Safe Work Condition.

9.1.2 ZVV is challenging because the worker is required to prove that something is not
there. One could stick the meter probes in the air or short them together and get
zero voltage, which is the expected reading, but that would not be a valid test.
Special testing techniques and protocols are therefore required to ensure a valid
test.

9.1.3 ZVV is intended to identify any remaining shock hazard present under the following
conditions:

a. Selection of wrong isolation point: In the case where Circuit A is to be

isolated, and the device for Circuit B is inadvertently selected as the isolation
point.

b. Mechanical or electrical failure of isolation device: The isolation device may

fail internally. One or all of the phases may still be closed even though the
device shows all external indications of being open.

c. Circuit backfeed or alternate power source: Another source of energy may

still be energizing the circuit. This could be an Uninterruptable Power
Supply (UPS), a temporary generator, incorrect wiring, or other source of
energy.

d. Residual charge: A circuit may retain a built-up capacitive charge, or may

be powered from a DC supply.

e. Adjacent energized components: Nearby energized components will present

an electrical hazard if they are not identified and controls put in place.
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9.1.4 ZVV is considered Mode 1 energized electrical work and requires a QEW. All
circuit parts shall be considered energized until the equipment has been placed
in an Electrically Safe Work Condition per
6.5. As such, the QEW is required to wear all PPE as if the test were a live
diagnostics test (Mode 2). However, the two-person rule is relaxed in Mode 1
compared to Mode 2.

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9.2 Live-Dead-Live Test Method

9.2.1 Whether used for ZVV or any supplementary voltage check (test before touch),
all voltage detectors shall be checked for proper function before and after each
use. This is known as the Live-Dead-Live test. The Live-Dead-Live test shall
consist of measuring or detecting voltage on a known energized circuit. The
known energized circuit can be:

a. A utility outlet

b. The line side of the isolation

c. A battery (resistive-type detectors only)

d. A proving unit specifically designed for this application

9.2.2 While not always feasible, it is highly preferable that the known live source be
as close as possible a match in voltage and waveform as the circuit to be
proven dead. The ideal test is to use the source immediately upstream of the
isolation point as the known live source.

9.3 Steps to perform ZVV

9.3.1 Test voltage on a known live source to verify meter function.

9.3.2 The following steps should be performed in order, where possible:

a. Verify absence of voltage difference, neutral-to-ground (for single phase

circuits). Verifies no floating neutral or shared neutral with current.

b. Verify absence of voltage difference, phase-to-ground on each phase. Keeps

meter referenced to ground for most of the test and keeps exposure lower
(i.e. 277 V vs. 480 V).

c. Verify absence of voltage difference, phase-to-neutral (if available). Provides a

backup test to phase- to-ground.
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 d. Verify absence of voltage difference, phase-to-phase on each phase (if
available). May be the only valid test on ungrounded systems.

9.3.3 Test voltage on a known live source again to verify meter function.

9.3.4 Do not change any meter settings or change the probes while performing Live-Dead-
Live.

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9.4 Where to perform ZVV

9.4.1 ZVV must be performed in such a manner as to PROVE that the LOTO that
was established has in fact isolated ALL sources of energy.

9.4.2 In addition, ZVV must be performed on ALL exposed conductors or parts that
will be touched or could be contacted by tools, wires, parts or other falling
objects.

a. Note that there cannot be any live voltage remaining inside an enclosure that
is being placed in an electrically safe work condition, even if the parts are
guarded or finger safe.

b. The ENTIRE enclosure must be dead and verified dead. If there is anything
live in a panel, Mode 0 work cannot be performed.

9.4.3 ZVV at the energy source(s):

a. Use ZVV to test each lockout isolation disconnect for absence of voltage as
close as possible to the disconnect to verify that the isolation is effective.

b. For this to be a valid proof, there can be no other component between the
disconnect and the test location that might be temporarily opening the circuit.
This includes fuses, contactors, thermal overloads and other disconnects.

c. Testing for absence of voltage is not valid when there is no voltage on the line
side of the intended lockout point. This happens frequently in outage
conditions where the isolations are at substations. Two options are available:
 Shift the lockout point for the duration of the lockout. The lockout
should be placed at the location upstream where there is still power on
the line side.
 For low voltage isolations only, shift the lockout point temporarily and
perform a continuity test through the intended isolation disconnect. Do
not perform the continuity test without locking out power to the line side

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 of the intended isolation. Continuity testing is not allowed for high
voltage isolations.

9.4.4 ZVV at the equipment:

a. Perform ZVV in the equipment to be worked upon immediately after opening

the electrical enclosure. This is to verify that the proper isolation was selected
and that there are no other sources of voltage remaining in the enclosure.
 Test the power entry terminals.
 Test every conductor to be touched. Testing must be done at each location
where conductors are going to be touched.
 Test behind any internal guard or barrier that is removed.

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 b. Additional verification may be performed with a proximity tester to ensure that
there are no foreign circuits being fed through, using the enclosure as a
raceway but without terminations to test with a contact tester.

c. If the scope of work requires cutting into insulation and there is no exposed
part to perform ZVV, see 9.7.

9.5 When to perform ZVV

9.5.1 Upon initially establishing an Electrically Safe Work Condition.

9.5.2 When any new conductor or circuit part is initially exposed by removing a
cover, opening a door, or removing a guard or barrier. This is the “first
exposure” rule.

9.5.3 When circuit conditions change, perform ZVV again before resuming work. This
includes:

a. When the LOTO is modified to change the LOTO safe zone.

b. When additional circuits are energized in parts adjacent to the LOTO safe zone.

9.5.4 When an isolation or lockbox is intentionally or unintentionally left unlocked and

unattended for any period of time, perform ZVV for any isolation for which
integrity was not maintained. For example, the RI lock is removed from a
lockbox and the lockbox is left unattended in a cart. An administrative lock is not
sufficient to maintain the integrity of a LOTO.

9.5.5 For cases other than those described in 9.5.1 through 9.5.4, supplementary
voltage checks may be performed on conductors or circuit parts that are still
in an Electrically Safe Work Condition, under LOTO and that were
previously verified dead using ZVV8.

a. When the job location has been left unattended, verify the integrity of the
LOTO and test before touch again before resuming work. This includes at a
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 minimum:
 Going offsite (off the Lab property)
 Leaving the job for more than 2 hours

b. Other supplementary voltage checks may be performed at the discretion of the

QEW or directed by the Person in Charge.

c. Supplementary voltage checks may be performed with a contact or

proximity tester, and do not require PPE. A live-dead-live check of the
voltage detector must still be performed.

d. If any part is discovered energized, the worker shall immediately stop work, notify
the Person In

8 The purpose of this clause is to encourage the frequent practice of Test Before Touch.
Although ZVV shall always be performed with a contact tester and wearing full PPE, this
should never prevent a QEW from satisfying their own need to prove absence of voltage
at any time or in any method of their choosing.

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 Charge, and notify the Laboratory ESO. Do not proceed with work. This
is a formal stop work condition. Establish a barricade and/or an attendant
around the area.

9.6 Types of Voltage Detectors

9.6.1 All voltage detectors used for ZVV shall be approved by an ESO. A list of voltage
detectors pre-approved for ZVV is included in Appendix E. For other types,
contact your ESO or the Electrical Safety Group.

9.6.2 Requirements for voltage detectors used for ZVV are:

a. Meet the requirements for Voltage Testers in 18.1.2.

b. Be of the two-pole contact type, except as allowed by Section 11.

c. Be digital high-impedance, except as allowed by 9.6.6.

d. Voltmeters with a resistance- or continuity-measuring feature shall have a

safety circuit built into the meter.

9.6.3 Permanently installed meters shall not be relied upon for ZVV, as a live
dead live test may not be performed.

9.6.4 Proximity testers (non-contact voltage testers) shall not be used alone for ZVV for
<750 VAC.

a. Proximity testers, also known as capacitive type detectors, are only designed
to detect AC voltage (50-60 Hz) above a certain threshold, sometimes as high
as 90 VAC.

b. As single pole devices, they do not have a clear reference to ground or to

another phase. While they are excellent tools for confirming presence of
nominal operating voltage, they are not always adequate for proving absence of
voltage.
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c. However, where there is a possibility that the contact probes do not make
certain contact with the conductor, as when testing though small ports or
before removing electrical insulating tape, a proximity detector shall be used
in addition to the contact voltmeter.

d. Proximity testers shall additionally be used as a pre-check prior to breaking

into insulation, like taped up motor connections, Molex connectors or wire
nuts, or before cutting an insulated wire,

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 where a contact tester cannot get good access to test. As soon as there is good
access, a follow up test is to be done with a contact tester.

9.6.5 Test probes must be selected to match the physical requirements of the test point.
Some test points are shielded, and the test leads must be narrow enough to fit
through access ports and long enough to reach the conductors.

9.6.6 High-Impedance vs. Low-Impedance Testing

a. Certain configurations of electrical/electronic equipment may induce voltages

on disconnected circuits. These are usually non-standard voltages different
from the nominal system voltage. Causes can include shared neutrals, floating
neutrals, residual capacitive charges from electronic circuits and coupling of
power waveforms across circuits.

b. Use of manufacturer-designed low-impedance adapters (such as the Fluke

SV225 Stray Voltage Eliminator) should be considered when there is the
possibility of small induced voltages to detect when those voltages would be
hazardous.

9.7 ZVV where there is no exposed conductor

9.7.1 NFPA 70E requires additional planning considerations that include methods of
verification where there is no accessible point to take voltage measurements. The
following are common situations and the appropriate methods are specified for
ZVV. In other cases not specified, contact an ESO for evaluation.

9.7.2 Cutting insulated conductors:

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a. Lockout/tagout the energy sources.

b. Wear shock protection PPE.

c. Separate out the phases and use a proximity tester to check to presence of
voltage. Use the live- dead-live method to verify function of the proximity
tester.

d. Use an insulated wire cutter to cut the wire.

e. If necessary to expose the conductor, use an insulated stripper to strip the

insulation.

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 f. Use a contact tester with alligator clips to perform ZVV on the exposed
conductor. Ensure the alligator clips also have a means to perform a valid
live-dead-live test on the available known energized source.

9.7.3 Disconnecting insulated splices:

a. Lockout/tagout the energy sources.

b. Wear shock protection PPE.

c. Separate out the phases and use a proximity tester to check to presence of
voltage. Use the live- dead-live method to verify function of the proximity
tester.

d. Use an insulated cutter to remove insulating tape or materials. Or

remove the wire nuts as applicable.

e. Use a contact tester with alligator clips to perform ZVV on the exposed
conductor. Ensure the alligator clips also have a means to perform a valid
live-dead-live test on the available known energized source.

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10 General Electrical Safe Work Practices

10.1 Minimum PPE for Electrical Work

10.1.1 The purpose of the minimum PPE requirement is to protect QEWs from injuries
sustained when the equipment is thought to be in an Electrically Safe Work
Condition (Mode 0). Many injuries occur after LOTO or Test Before Touch
have been incorrectly performed. The minimum PPE will not fully protect the
worker, but can significantly reduce the likelihood of a life-altering injury.

10.1.2 The minimum PPE requirement applies at all times when performing electrical
work, even when it has been placed in an Electrically Safe Work Condition.

a. Exception: Minimum PPE does not apply to electrical work on 120 VAC
cord-and-plug equipment that has been unplugged.

b. Exception: Minimum PPE does not apply to rough-in electrical construction work.

10.1.3 At a minimum, all QEWs performing electrical work shall wear:

a. Safety glasses, and

b. Non-melting clothing to include long pants and long sleeves, and

c. Non-melting safety footwear that fully covers the feet.

10.1.4 Note that some QEWs that work with arc flash hazards (QEW 2 and QEW 3)
have daily arc-rated wear as described in 8.13 instead of non-melting clothing.

10.2 Body Positioning

10.2.1 Body positioning is a fundamental concept in safe electrical work practices.

Nearly all of the required and recommended electrical safe work practices are
directly related to body positioning. The QEW should learn to visualize their
physical interaction with the equipment in advance in order to fully integrate
these requirements into a cohesive set of safe electrical work habits.
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10.2.2 Note that the shock approach boundaries are also related to body positioning. See
7.3.2.b and 7.3.3.a. Barriers and PPE are used to complement body positioning
techniques where these may not be sufficient to prevent electrical shock.

10.2.3 Proper body positioning for shock protection is primarily related to inadvertent
movement and should incorporate an understanding of the following elements:

a. Balance

b. Safe approach vector

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10.2.4 Balance is necessary to prevent falling forward into energized components.
Proper body positioning includes a stable stance, on a level standing surface. The
worker shall consider how to position his or her body to minimize the chance of
incidental contact with exposed energized conductors. The worker shall always
position his or her body in such a way as to reduce the likelihood of slipping,
tripping or falling into energized equipment. Examples include:

a. The worker should avoid bending over at the waist to perform electrical work,
as this could lead to falling into energized gear.

b. Where there is a risk that doors, hinged panels, and the like could swing into an
employee and cause the employee to contact exposed energized electrical
conductors or circuit parts, they shall be secured to prevent swinging.

c. When accessing a cabinet above the worker’s eye level, the worker shall
use an approved non- conductive step-stool or step-ladder to provide
adequate access. Non-approved items such as toolboxes, buckets, or
miscellaneous parts are not allowed for access to electrical equipment.

d. When working in an area with pedestrian traffic, the QEW should establish
alerting techniques (signs, barricades and/or attendants per 10.3) at a
sufficient distance to prevent anyone from bumping into the QEW while
work is being performed.

10.2.5 Safe approach vector incorporates balance while purposefully moving towards
energized gear.

a. The worker shall consider how best to approach exposed live components.

b. Walking directly towards exposed live gear is not recommended, as a slip,

trip or fall would cause the worker to fall directly towards the exposed gear.
Instead, workers should approach with an indirect route.

c. Kneeling down or bending directly in front of exposed live gear is also not

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 recommended. Instead, the worker should get down on the knees at some
distance away from the cabinet, then approach the cabinet to perform the
work from a kneeling or sitting position.

10.2.6 Older techniques for shock protection derived from bare hand methods. While
bare hand work is no longer authorized, the techniques are still good practice,
especially when performing visual inspection of energized panels:

a. Placing left hand in the pocket to avoid a shock pathway through the heart

b. Standing on rubber insulating mats as secondary protection

10.2.7 Proper body positioning for arc flash protection is primarily related to the concept of
Line of Fire.

a. This is the understanding that certain hazards have directionality when things go
wrong. Some arc

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 flash hazards are very directional (see 2.3.3.b and 8.14).

b. For this reason, when operating a load-rated switch, circuit breaker, or other
device specifically designed as a means for a disconnect, the worker should
position his or her body to the side of the circuit breaker to minimize the
exposure to the body should an arc blast occur during the operation.

10.2.8 Steps for proper body positioning for arc flash:

a. Determine the busbar configuration where the arc flash is likely to occur.
 Vertical
 Horizontal

b. Determine the source side of the busbar (top, bottom, left, right). The
convective flow will be directed along the busbar away from the source.

c. Determine if the panel configuration will redirect the ejected plasma.

d. Determine the line of fire based on b and c.

e. Determine body positioning such that the worker is not in the line of fire.
If the work must be performed in the line of fire, consider:
 Upgrading the arc flash PPE ensemble to a higher level
 Using arc-rated blankets or other suitable barriers

f. Ensure that when turning away, the arc rated flash suit hood is not pulled up
around the shoulders to expose the skin.

10.2.9 Proper body positioning for switching is primarily a protection for arc blast:

a. Stand to the side. Where possible, do not reach across the panel to the switch
handle, instead stand on the same side of the panel as the switch handle.

b. Place hand on the switch handle but do not operate the switch.

c. Face away from the switch, close the eyes, take a deep breath and hold it.
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d. Forcefully throw the switch in a complete full motion.

e. Verify system response.

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10.3 Controlling the Work Area (Alerting Techniques)

10.3.1 The Person In Charge (PIC) shall ensure the safety of bystanders by controlling
access to the electrical work area. The PIC may perform this task in person,
delegate it to an attendant, set up barricades and signs, or use a combination
thereof. The type of controls necessary depends on the severity of the hazard
involved and the likelihood of unauthorized entry into the work space. In all
cases, unauthorized personnel shall be kept outside of the limited approach
boundary or the arc flash boundary, whichever is greater.

10.3.2 Signs

a. Safety signs, safety symbols, or accident prevention tags shall be used

where necessary to warn employees about electrical hazards, which may
endanger them.

b. The person in charge of the work shall be responsible to place these

signs and tags where appropriate and ensure they meet regulatory
requirements.

c. Appropriate signs shall be placed at suitable intervals to specify the nature of

the hazard and the expectations for personnel in the area. The sign will
indicate the hazard exposure and instructions such as “KEEP OUT”, or
“APPLY LOTO PRIOR TO ENTRY”.

d. Use the signal word and color in Table 10.3.1 for signage.

e. Signage is mandatory for Mode 2 and Mode 3 work.

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 Mod Signal Word/Color
e
Switching (optional)

Mode 0 (optional)

Mode 1 (optional)

Mode 2 (mandatory)

Mode 3 (mandatory)

Table 10.3.1 – Signal Word and Color for Temporary Signs and Barricades

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10.3.3 Barricades

a. Barricades shall be used in conjunction with barricade tape and signs

where it is necessary to prevent or limit employee access to work areas
exposing employees to exposed non-insulated energized conductors or
circuit parts.

b. Conductive barricades shall not be used where it might cause an electrical

hazard. The person in charge of the work shall be responsible to evaluate the
need for barricades on a case-by-case basis.

c. Barricades shall be installed no closer than the limited approach boundary or

the arc flash boundary, whichever is greater. While the barricade is being
installed, the restricted approach boundary distance shall be maintained, or the
energized conductors or circuit parts shall be placed in an Electrically Safe
Work Condition.

d. Use the signal word and color in Table 10.3.1 for barricade tape.

e. Barricade tape is mandatory for Mode 2 and Mode 3 work.

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A DANGER barricade and sign indicating live testing and troubleshooting (MODE 2)

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A note on ANSI Z535 Signal Word Selection and application to Electrical Hazards:

For hazard alerting signs and barricade tapes, the signal word is selected according
to the risk presented by the hazardous situation that the safety message addresses. In
other words, signal word selection is based on the risk posed if the safety sign or
barricade tape is not followed.

The risk is determined based on:

a. worst credible severity of harm if an accident occurs;

b. probability of an accident if the hazardous situation occurs (i.e., if the
safety sign or barricade tape is not followed); and
c. probability of the worst credible severity occurring.

Probability of Accident if
Hazardous Situation is Not
Avoided
Will Could

Will
Probability of MODE MODE
2/3 1
Death or
Serious Injury
Coul
if Accident NOT NOT
d
Occurs USED USED

If the worst credible severity is minor or moderate injury:

For all
Probabilities NOT USED
Because Electrical Shock or Arc Flash Hazards are always potentially Fatal or
Serious, the CAUTION signal word is not used.

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If there is no credible risk of physical injury:

For all
Probabilities MOD
E0

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10.3.4 Attendants

a. An Attendant is a person who is helping to warn other personnel about

electrical hazards, which may endanger them. An Attendant may be a QEW
or a non-QEW. An Attendant may also be assigned duties as a Standby
Person or a Safety Watch (6.13).

b. An Attendant is required when normal alerting techniques such as safety

signs, barricades are not sufficient to prevent or limit access to exposed
energized conductors or circuit parts (10.3.4).

c. The person in charge of the work shall be responsible to evaluate the need for
attendants on a case- by-case basis.

d. The Attendant shall:

 Remain in the area as long as there is a potential for employees to
be exposed to the electrical hazards
 Be stationed outside the barricade
 Provide manual signaling and alerting to keep non-QEWs outside a work
area where the non- QEW might be exposed to electrical hazards.

10.3.5 Look-Alike Equipment

a. Where work performed on equipment that is de-energized and placed in an

Electrically Safe Work Condition exists in a work area with other energized
equipment that is similar in size, shape, and construction, one (or more) of the
altering methods in 10.3.1, 10.3.3, or 10.3.4 shall be employed to prevent the
employee from entering look-alike equipment.

10.4 Other Precautions for Personnel Activities

10.4.1 Alertness

a. When Hazardous. Electrical Workers shall remain alert at all times when they
are working within the limited approach boundary of energized electrical
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 conductors or circuit parts operating at 50 volts or more and in work situations
where electrical hazards might exist.

b. When Impaired. Electrical Workers shall not be permitted to work within the
limited approach boundary of energized electrical conductors or circuit parts
operating at 50 volts or more, or where other electrical hazards exist, while
their alertness is recognizably impaired due to illness, fatigue, or other reasons.

c. Changes in Scope. Electrical Workers shall remain alert for changes in the job
or task that may lead the person outside of the Electrically Safe Work
Condition (LOTO Safe Zone) or expose the person to additional hazards that
were not part of the original plan. Also see 4.6.4 and 6.12.5.

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10.4.2 Blind Reaching. Electrical Workers shall never reach blindly into areas that
might contain exposed energized electrical conductors or circuit parts where
an electrical hazard exists.

10.4.3 Illumination

a. General. QEWs shall not enter spaces containing electrical hazards unless
illumination is provided that enables the employees to perform the work
safely.

b. Obstructed View of Work Area. Where lack of illumination or an obstruction

precludes observation of the work to be performed, QEWs shall not perform
any task within the Limited Approach Boundary.

10.4.4 Conductive Articles Being Worn:

a. Conductive articles of jewelry and clothing (such as watchbands, bracelets,

rings, key chains, necklaces, metalized aprons, cloth with conductive thread,
metal headgear, or metal frame glasses) shall not be worn where they present
an electrical contact hazard with exposed energized electrical conductors or
circuit parts.

b. In all cases conductive articles of jewelry and clothing shall be removed

from the worker’s body prior to entering the Restricted Approach
Boundary.

10.4.5 Conductive Materials, Tools, and Equipment Being Handled

a. General. Conductive materials, tools, and equipment that are in contact with
any part of an employee’s body shall be handled in a manner that prevents
accidental contact with energized electrical conductors or circuit parts. Such
materials and equipment shall include, but are not limited to, long conductive
objects, such as ducts, pipes and tubes, conductive hose and rope, metal-lined
rules and scales, steel tapes, pulling lines, metal scaffold parts, structural

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 members, bull floats, and chains.

b. Approach to Energized Electrical Conductors and Circuit Parts. Means shall be

employed to ensure that conductive materials approach exposed energized
electrical conductors or circuit parts no closer than that permitted by 6.4. When
long conductive objects are handled in the vicinity of exposed energized
conductors or circuit parts, each end of the object should be under the control of
different persons. For example, a length of metal pipe should be handled by
assigning one person to each end of the pipe.

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10.4.6 Confined or Enclosed Work Spaces. When an employee works in a confined or
enclosed space (such as a manhole or vault) that contains exposed energized
electrical conductors or circuit parts operating at 50 volts or more, or where an
electrical hazard exists, the employer shall provide, and the employee shall use,
protective shields, protective barriers, or insulating materials as necessary to
avoid inadvertent contact with these parts and the effects of the electrical
hazards.

10.4.7 Foreign Body Exclusion. Care should be taken to prevent objects from falling
into electrical panels or equipment.

10.4.8 Housekeeping

a. Cleaning inside electrical cabinets shall not be performed unless the cabinet
has been placed in an Electrically Safe Work Condition.

b. Personnel performing cleaning around the exterior of cabinets that have not
been placed in an Electrically Safe Work Condition shall be mindful to
prevent foreign debris, sprays and dusts from entering the cabinet.

c. Combustible materials shall not be stored around electrical equipment or in

electrical rooms. Paperwork related to the electrical equipment may be left in
electrical rooms when stored in closed metal cabinets.

d. A clear working space shall be maintained in the front of electrical

enclosures in accordance with 5.11.

10.4.9 Occasional Use of Flammable Materials

a. Where flammable materials are present only occasionally in Unclassified

Locations, electric equipment capable of igniting them shall not be permitted to
be used, unless measures are taken to prevent hazardous conditions from
developing.

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 b. Such materials shall include, but are not limited to, flammable gases, vapors, or
liquids; combustible dust; and ignitable fibers or flyings.

c. This does not apply to equipment used in Classified Locations per the NEC,
where fire or explosion hazards may exist more than occasionally due to
flammable gases, flammable liquid–produced vapors, combustible liquid–
produced vapors, combustible dusts, or ignitable fibers/flyings.

10.4.10 Anticipating Failure

a. When there is evidence that electric equipment could fail and injure
employees, the electric equipment shall be de-energized, unless line
management can demonstrate that de-energizing introduces additional
hazards or increased risk or is infeasible because of equipment design or
operational limitation.

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 b. Evidence that electric equipment could fail includes:
 Loose or bound equipment parts
 Overheating
 Deterioration
 Any indication of severe electrical failure per 10.4.11.a

c. Contact an Electrical Safety Officer immediately for guidance. For

additional guidance on this justification, see 6.4.4.c and 6.4.4.d. Keeping
the equipment running may require an EEWP.

d. Until the equipment is de-energized or repaired, employees shall be

protected from hazards associated with the impending failure of the
equipment by suitable barricades and other alerting techniques necessary for
safety of the employees.

10.4.11 Deranged Equipment

a. Whenever electrical equipment has been subjected to a severe electrical failure,

it is considered deranged equipment until its electrical integrity can be verified
by testing and inspection. The normal means of deenergization may not be
sufficient. Indications of severe electrical failure include but are not limited to:
 Smoke, charring or fire
 Arcing, arc flash or arc blast
 Severe physical damage or deformation
 Report of sparking
 Report of electric shock

b. Determining if equipment is deranged is a judgment call. Employees should err

on the side of caution. Deranged equipment must be treated with more caution
than equipment in normal operating condition. Normal lockout and
deenergization procedures may not be sufficient to provide adequate safety.

c. Prior to beginning work on deranged equipment, a shock and arc flash

hazard analysis must be conducted with an Electrical Safety Officer.

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 d. Depending on the results of the hazard analysis, initial zero voltage
verification (ZVV) may need to be performed on the cabinet external casing
and other normally grounded metal surfaces. Voltage gloves are required for
these tests.

10.4.12 Routine Opening and Closing of Circuits

a. Load-rated switches, circuit breakers, or other devices specifically designed as

disconnecting means shall be used for the opening, reversing, or closing of
circuits under load conditions.

b. Cable connectors not of the load-break type, fuses, terminal lugs, and cable splice
connections shall

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 not be permitted to be used for such purposes, except in an emergency.

10.4.13 Reclosing Circuits After Protective Device Operation

a. After a circuit is de-energized by the automatic operation of a circuit

protective device (such as a circuit breaker trip or blown fuse), the circuit
shall not be manually reenergized until it has been determined that the
equipment and circuit can be safely energized.

b. The repetitive manual reclosing of circuit breakers or reenergizing circuits

through replaced fuses is prohibited.

c. When it is determined that the automatic operation of a device was caused by

an overload rather than a fault condition, examination of the circuit or
connected equipment shall not be required before the circuit is reenergized.

10.4.14 Safety Interlocks

a. Only qualified persons following the requirements for working inside the
restricted approach boundary as covered by 7.3.3.c shall be permitted to
defeat or bypass an electrical safety interlock over which the person has sole
control, and then only temporarily while the qualified person is working on
the equipment.

b. The safety interlock system shall be returned to its operable condition when the
work is completed.

10.4.15 Disconnection/reconnection of wires

a. Wires shall not be disconnected or reconnected without first being in an

Electrically Safe Work Condition.

b. Disconnected wires shall not be reenergized.

c. Pending permanent removal, permanently disconnected wires shall be

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 disconnected at the power supply end and tagged out at the power supply end
in accordance with the Lockout/Tagout Program.

d. Temporarily disconnected wires may be disconnected at the load end only,

provided that their power supply remains locked out for the duration. If the
power supply isolation for the wires needs to be closed to power up other
loads, then the wires need to be disconnected at both ends, and locked out at
the power supply end in accordance with the Lockout/Tagout Program
 Note: After safing off the wire line-side ends, tape a solid object to the
wires and affix a cord cap box and LOTO lock. This avoids the use of a
Tagout-Only situation.

e. The phase wires shall be disconnected first, followed by the neutral wire, followed
by the earth wire.

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 f. All disconnected wire ends shall be electrically insulated, using
electrician’s tape, wire nuts, or another suitable insulator.

g. Any wires that are discovered bare shall be treated as energized. A qualified
electrical worker shall be called to investigate and make the condition safe.

10.4.16 Electrical Single Line Drawings

a. Electrical single line drawings shall be made available for QEWs in the field,
either through physical copies or electronic access.

b. All Facilities Distribution High Voltage Switch Stations shall have a single line
drawing of the relevant circuits posted in the switch station. The drawings shall
be laminated and posted on the wall or be stored in a designated and labelled
metal cabinet.

c. All electrical single lines shall be kept current.

10.4.17 Light Fixtures

a. Light fixtures that are designed to allow bulb replacement while preventing
incidental contact with exposed energized circuit parts are not required to be
placed in an Electrically Safe Work Condition to replace the light bulbs.

b. Replacement of the ballasts or of the light fixture itself shall require that the
fixture be placed in an Electrically Safe Work Condition. Energized
replacement of these items is prohibited and is not justified under an
Energized Electrical Work Permit.

10.4.18 Cabinet Enclosures

a. All electrical cabinet covers shall be closed and fully bolted or latched
when not opened for inspection or work.

b. When temporary cables are required to be placed through a cover opening,

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which prevent closing and latching the cover, the cabinet shall be treated as if
it were opened. All electrical approach boundaries and PPE requirements
shall be in effect.

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11 High Voltage Facilities Distribution Systems (>750 VAC)

11.1 Scope

11.1.1 This section applies to Berkeley Lab owned or operated facilities distribution
installations where nominal system voltage exceeds 750 VAC. This also
includes programmatic equipment >750 VAC directly connected to facilities
distribution equipment. It does not cover open-air switchyards or substations,
but is limited to the operation and maintenance of metal clad or metal enclosed
medium voltage switchgear and transformers, and associated equipment.

11.1.2 High Voltage DC installations or equipment are not within the scope of this section
(see section 12).

11.2 Qualification requirements

11.2.1 All persons performing work on high voltage facilities distribution systems
shall be qualified to level QEW 3. This includes persons performing the role of
Electrical Standby Person.

11.3 Restricted Access to High Voltage Enclosures

11.3.1 In all electrical work, test before touch is a fundamental principle. However, if a
QEW 1 or QEW 2 were to unknowingly test a high voltage circuit with a tester
that is not properly rated, serious injury or death would ensue. Therefore, it is
imperative that high voltage circuits are kept marked and nominally out of reach
from casual access.

11.3.2 All high voltage electrical enclosures shall be marked with a high voltage danger
label that includes the highest nominal operating voltage in the enclosure.

11.3.3 All high voltage electrical enclosures with hinged doors or panels shall be kept
locked closed with a HV Admin Lock controlled by the Electrical Utilities
Coordinator. Trapped key interlock systems satisfy and exceed this requirement.

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11.3.4 All non-load-rated high voltage disconnect switches shall be kept locked with a
HV Admin Lock in their normal operating position (closed or open) to prevent
operation under load. Trapped key interlock systems satisfy and exceed this
requirement.

11.3.5 High voltage components shall not be located in low voltage enclosures that
typically require access by others who are not QEW Level 3. Where this is
unavoidable, the enclosure shall be considered a high voltage enclosure, subject
to the restrictions in this section.

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11.4 Switching

11.4.1 All high voltage switching activities shall be performed under an approved
Switching Tag, which is a form of an Electrical Safe Work Procedure. The
Switching Tag shall be prepared, reviewed and approved by separate persons
qualified as QEW3.

11.4.2 All high voltage work shall be supervised by a QEW 3 designated as Person In
Charge.

11.4.3 The Electrical Utilities Coordinator shall maintain a High Voltage Distribution
Status Board, consisting of a single-line diagram of the high voltage distribution
system operated by the Lab, and displaying all connections to the utility. The
status board may be physical or electronic. The status board shall be kept updated
with temporary markings indicating any switches out of their normal operating
position, and the location of all temporary wiring, temporary grounds and
temporary generators connected to the system.

11.4.4 High voltage vacuum circuit breakers shall be fully racked out to the disconnect
position for LOTO. The LOTO lock shall physically prevent racking in the
breaker. If the breaker is to be removed for testing, then the racking mechanism
or door shall be locked out to prevent racking in another breaker. If necessary,
lockout the shutter assembly or the door to the breaker enclosure to prevent
access to the line side connections of the breaker.

11.4.5 Where possible, high voltage circuit breakers of the drawout type shall be
racked in and out with remote racking mechanisms that allow the High Voltage
Operator to stay outside of the switch room. Remote racking mechanisms shall
be approved by the Electrical Utilities Coordinator, with torque interlocks to
prevent jamming. Where remote operation is not possible, a QEW 3 electrical
safety watch is required according to 6.13.4.

11.4.6 Where possible, high voltage circuit breakers shall be opened and closed
remotely, with remote operating devices that allow the High Voltage
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 Operator to stay outside of the switch room. Where remote operation is not
possible, a QEW 3 electrical safety watch is required according to 6.13.4.

11.5 Zero Voltage Verification

11.5.1 Zero Voltage Verification (ZVV) of high voltage circuits shall conform to
Section 9, as amended in this section.

11.5.2 The preferred method for ZVV is to use a proximity type detector on a hot stick,
followed by application of temporary personal protective grounds with a hot stick,
both wearing full PPE for shock and arc flash protection. This requires grounding
points that are very accessible, usually using a combination of ball studs and
matching clamps.

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11.5.3 Because this configuration is often not available, the next best method for ZVV
is to use a proximity type detector on a hot stick, followed by a contact type
detector on a hot stick, both wearing full PPE for shock and arc flash protection.
Then if grounds are immediately installed after checking with proximity and
contact tester, the grounds may be placed by hand without PPE.

11.5.4 In all cases, the Live-Dead-Live check is performed with a portable tester. The
self-check feature in some detectors is considered a secondary indication but
shall not be used for the Live-Dead-Live check of the detector.

11.6 Personal Protective Equipment

11.6.1 Shock Protection

a. In high voltage applications, primary shock protection is provided by an

insulated live-line tool, usually called a hot stick. Only a hot stick of a
sufficient length can provide the standoff distance necessary to safely meet
the Restricted Approach Boundary requirements for the whole body.

b. Live-line tools shall conform to ASTM F711, Standard Specification for

Fiberglass-Reinforced Plastic (FRP) Rod and Tube Used in Live Line Tools.
They shall be of sufficient length that the QEW can handle the tool without
having the hands enter the Restricted Approach Boundary.

11.6.2 Arc Flash Protection

a. Arc flash PPE shall be worn based on an arc flash hazard analysis in
accordance with 8.1. Arc-rated gloves may be needed when using a hot stick
without wearing rubber insulating gloves.

b. Note that the working distance for medium voltage switchgear is usually 36
inches. This is the typical working distance when working with a hot stick.
Working closer than 36 inches raises the arc flash incident energy considerably.
For example, an incident with a calculated energy of 6.2 cal/cm 2 at 36 inches
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 becomes about 12.3 cal/cm2 at 18 inches9.

11.7 Temporary Personal Protective Grounding of High Voltage Circuits

11.7.1 Purpose: The installation of Temporary Personal Protective Grounds at the

work location protects employees from the following hazards:

a. Accidental closing: Although all potential feeds for a deenergized circuit are
required to be locked out prior to the commencement of work, the possibility
of someone inadvertently energizing the circuit still remains.

b. Accidental Contact: A deenergized circuit could come in contact with another

energized circuit or

9 Assumptions: IEEE 1584 formulas with 12.47 kV switchgear, 10 kA bolted fault, 30

cycle clearing time, using EasyPower online arc flash calculator.

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 the deenergized circuit could be energized through human error.

c. Equipment Failure: The insulation of the switching devices opened to

deenergize the circuit could either break down or track over, and energize the
line on which work is being done.

d. Backfeed: In addition to the primary sources, there are several secondary

sources that can cause current to flow in a deenergized circuit. Some
examples of these sources include tie breakers, instrument transformers,
metering installations and auxiliary generators.

e. Induced voltage: A hazardous voltage can be induced by proximity to other

energized high voltage lines.

f. Charge build-up: the capacitance of high voltage cables can store a hazardous
charge after isolation from the source.

11.7.2 Movement of Temporary Personal Protective Grounds: The magnetic fields

produced when large currents flow through grounding cables will cause the
cables to whip violently. For this reason, grounding cables should be kept as
short as possible and placed such that workers are not injured should whipping
of cables occur. Excess length shall not be coiled, as this can add significant
impedance, delay operation of the overcurrent protective device and cause
explosive whipping of the cable.

11.7.3 Choosing the right type of Temporary Personal Protective Grounds

a. Only approved grounding cables and clamps shall be used for personal
protective grounding. Temporary personal protective ground assemblies shall
conform to ASTM F855, Standard Specifications for Temporary Protective
Grounds to Be Used on De-energized Electric Power Lines and Equipment.

b. Cables may be jacketed with clear or yellow jacketing. Clear jacketing

allows inspection of underlying cables, while high-visibility yellow
Page 195 of 217
 jacketing helps prevent leaving grounds applied for restoration.

c. Temporary personal protective ground assemblies shall be rated for the

amount of available bolted fault current at the point of installation. Refer to the
short circuit studies for a calculation of available bolted fault current.

d. The ground position of a gas switch may be used in the place of temporary
personal protective grounds.

e. When using a grounding and testing device (ground cart) in a breaker

enclosure, the ground cart shall be locked in place. Prior to inserting the ground
cart, the cover shall be locked with an HV Admin Lock in the correct position
(top or bottom) to cover the side that will remain energized. Only

Page 196 of 217

 listed ground carts from the manufacturer shall be approved for use.

11.7.4 Where to apply Temporary Personal Protective Grounds

a. Temporary personal protective grounds shall be applied directly downstream

of the LOTO isolation, and can be applied at either end of a cable run.

b. Temporary personal protective grounds shall never be installed in series with a fuse
or switch.

c. Grounding clamps shall not be installed over cable termination lugs, as these
are likely to separate under the stress of a short circuit.

11.7.5 Applying Temporary Personal Protective Grounds

a. Before applying grounds to any conductor, all potential sources to the

conductor shall be isolated and locked out in accordance with the LOTO
procedure, then tested for the absence of voltage with an approved tester, using
the Zero Voltage Verification (ZVV) procedure in 11.5. Application of
grounds on an energized circuit will likely result in a serious injury or fatality.

b. Each QEW 3 that participates in ZVV or the application of grounds shall

first apply personal LOTO locks for all of the isolations. This can be directly
at the isolations or on a group lockbox.

c. The surfaces of all grounding connections must be visually checked free of

surface corrosion or coating. If necessary, clean the connection point where
ground clamps are to be applied using an approved live-line tool rated for the
nominal line-to-line voltage of the circuit. On surfaces likely to be corroded,
such as Ufer ground cables or other grounding electrode conductors exposed
to the elements, use Class B clamps with serrations or teeth to bite through.

d. When applying Temporary Personal Protective Grounds to deenergized

equipment, the grounding cables shall be connected to the ground before
being brought near the conductor that is to be grounded. Temporary Personal
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 Protective Grounds should be carefully laid out, and if necessary, tied
securely so as not to present a hazard to the workers. All grounding
connections should be made so they do not interfere with the work.

11.7.6 Control of Temporary Personal Protective Grounds

a. The use and placement of all temporary personal protective grounds

shall be continuously controlled by a Complex LOTO Procedure in
accordance with the Lockout/Tagout Program.

11.7.7 Removing Temporary Personal Protective Grounds

a. Each QEW 3 shall apply personal LOTO locks for all of the isolations on the
LOTO procedure while removing grounds. This can be directly at the
isolations or on a group lockbox.

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b. When removing grounds, the grounding cable to each conductor shall be first
removed using a live- line tool before the ground connection point is removed.

c. Grounds may be removed temporarily for testing. When reapplying grounds

after testing, follow the requirements of 11.7.5, including ZVV and PPE.

Page 199 of 217

12 High Voltage/Low Current DC Systems (>1000 VDC, <40 mA)

12.1 Hazards

12.1.1 When the output current of high-voltage supplies is below 40 mA, the shock
hazard to personnel is low. Where combustible atmospheres or mixtures exist, the
hazard of ignition from a spark may exist. High- voltage supplies can present the
following hazards:

a. Faults, lightning, or switching transients can cause voltage surges in excess of the
normal ratings.

b. Internal component failure can cause excessive voltages on external

metering circuits and low- voltage auxiliary control circuits.

c. Overcurrent protective devices, such as fuses and circuit breakers for

conventional applications, may not adequately limit or interrupt the total
capacitive or inductive energy and fault currents in highly capacitive or
inductive DC systems.

d. Stored energy in long cable runs can be an unexpected hazard. Safety

instructions should be in place to ensure proper discharge of this energy.

e. Secondary hazards, such as startle or involuntary reactions from contact

with high-voltage/low- current systems, may result in a fall or entanglement
with equipment.

12.2 Design Considerations

12.2.1 Personnel in R&D labs may encounter energized parts in a variety of

configurations, locations, and under environmental conditions that are not
usual for most electrical power personnel.

12.2.2 Sometimes the equipment can be designed to incorporate engineered

controls that mitigate the hazards associated with working on such
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 equipment. If not, safe operating procedures should be developed and used.

12.3 Safety Practices

12.3.1 An analysis of high-voltage circuits should be performed by a qualified person

before work begins, unless all exposed energized parts are guarded. The
analysis should include fault conditions in which circuit current could rise
above the nominal rated value.

12.3.2 If the analysis concludes that the current is above 40 mA or stored high-voltage
capacitive energy is above the shock thresholds for capacitors in Table 2.2.13,
then the work is considered to be electrical work and shall be performed in
accordance with Section 6.

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12.3.3 High-voltage supplies that use rated connectors and cables, when there are no
exposed energized parts, are not considered hazards. Connections shall not be
made or broken with the power supply energized, unless they are designed and
rated for this type of duty (e.g., load-break elbows). Inspect cables and
connectors for damage and do not use if they are damaged. Exposed high-
voltage parts should be guarded to avoid accidental contact.

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13 Distributed Generation

13.1 Permanently connected standby generators

13.1.1 Standby generators shall have a posted single-line diagram. The diagram
will not be just the manufacturer’s manual drawing, as these often do not
show hardwired tie-ins and isolations.

13.1.2 The diagram will include AC output to the load, AC output to the load bank,
battery charging input, block heater input, and all connections to premises
wiring.

13.2 Portable generator connection and operation

13.2.1 For all portable generators, the generator neutral shall be securely bonded to the
generator ground bar. The generator ground bar shall be securely bonded to a
reliable grounding point, preferably to an available building ground. Where a
reliable building ground is not available, a grounding rod shall be driven into the
ground next to the generator, except as noted in 13.2.2.

13.2.2 Under the following conditions, the frame of a portable generator need not be
grounded (connected to earth) and that the frame may serve as the ground instead.
If these conditions do not exist, then a grounding electrode, such as a ground rod,
is required:

a. The generator supplies only equipment mounted on the generator and/or cord-
and plug-connected equipment through receptacles mounted on the generator,
and

b. The noncurrent-carrying metal parts of equipment (such as the fuel tank, the
internal combustion engine, and the generator’s housing) are bonded to the
generator frame, and the equipment grounding conductor terminals (of the
power receptacles that are a part of [mounted on] the generator) are bonded to
the generator frame. Thus, rather than connect to a grounding electrode
system, such as a driven ground rod, the generator’s frame replaces the
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 grounding electrode.

13.2.3 All temporary electrical installations connected to the portable generator shall
require an equipment protection ground conductor from the generator to the final
utilization equipment. The grounding conductor shall be bonded to grounding
point at the generator only. Metal enclosures for intermediate distribution boxes
shall also be bonded to the grounding conductor.

13.2.4 All utilization equipment powered from temporary electrical installations shall be
protected with GFCI’s (Ground Fault Current Interrupters). Portable GFCI’s shall
be installed between the distribution panel and the temporary cable feeding the
utilisation equipment.

13.2.5 Electrical engineering expertise shall be consulted to obtain detailed

specifications for proper grounding techniques, materials, and GFCI’s.

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13.2.6 When portable generators will be used, the LOTO Coordinator shall coordinate
with all affected persons (including customers and contractors where applicable)
to ensure that everyone knows of the possibility of electrical backfeed.

13.2.7 A Lockout Procedure shall be established in accordance with the Lockout/Tagout

Program to prevent electrical backfeed prior to wiring in the portable generator.
Only circuits requiring power shall be fed through the temporary generator.
Other normally connected circuits shall be disconnected and locked out if they
are not required to be energized.

13.2.8 The LOTO Coordinator shall review all Lockout Procedures currently in use and
verify that they are adequate and take into consideration the possibility of
electrical backfeed. Lockout Procedures shall be modified where required.

13.2.9 The portable generator wires must be completely removed from the
enclosure prior to allowing restoration of normal power to the enclosure.

13.3 Uninterruptible Power Systems (UPS)

13.3.1 This section applies to permanently installed hardwired UPS. It does not
apply to cord-and-plug desktop or rack-mounted UPS.

13.3.2 Hardwired UPS come in multiple configurations and do not have a standardized
wiring scheme. The ability to bypass the UPS for maintenance includes the
ability to run the UPS output and the normal power output at the same time for
a short time in order to transfer power without interrupting the load. A phase
monitoring and switch interlock system is normally used to prevent paralleling
the UPS output breaker with the bypass breaker out of phase. Proper switching
sequence is sometimes reinforced by the application of trapped key interlock
systems. However, the operator should have a detailed understanding of the
UPS configuration and switching requirements and should not intentionally
defeat the switching interlocks.

13.3.3 The equipment owner (whether Facilities or Program) shall be responsible for
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ensuring that hardwired UPS with switching have the following:

a. Posted single-line diagram. The diagram will not be just the manufacturer’s
manual drawing, as these often do not show hardwired tie-ins and
isolations. The diagram shall include AC and DC isolations for all inputs
and outputs, with breaker designations.

b. Where a mimic bus is displayed on the UPS, it shall be correct for the actual site
installation.

c. Posted switching procedure. All switching procedures for the UPS, including
switching from normal to bypass, bypass to normal, complete shutdown,
complete startup, and other commonly used switching procedures, will be
posted in the vicinity of the UPS.

Page 206 of 217

14 Batteries

14.1 Scope

14.1.1 This section covers hazardous batteries that are used in the following typical
applications:

a. Energy storage;

b. Voltage multipliers;

c. Filters; and

d. Isolators.

14.1.2 Hazardous batteries include the following:

a. ≤100 and >1kW, or

b. >100 V

14.1.3 Batteries are used in multiple applications. Specialized types exist that are
suitable for different applications.

14.1.4 Lead-acid storage battery types are the lead-antimony and the lead-calcium. The
lead-antimony battery is low cost, high efficiency, small size and long life.
Typically, the lead-calcium is chosen for use in UPS systems due to the similar
characteristics of lead-antimony coupled with lower maintenance requirements.
Both types use dilute sulfuric acid as the electrolyte.

14.1.5 Alkali storage battery types are the nickel cadmium and the nickel metal
hydride. These batteries use compounds of nickel peroxide and iron oxide for
the plate materials, and potassium hydroxide as the electrolyte. Storage batteries
of this type perform well in extremes of temperature.

14.1.6 Other Batteries. Specialized batteries for applications include lithium ion,
Page 207 of 217
 silver zinc, silver cadmium and mercury. Manufacturers’ data sheets provide
guidelines for safety for these and other battery types.

14.2 Qualification & Training

14.2.1 Only Qualified Electrical Workers may perform work on battery systems rated at
>100 VDC.

14.2.2 All personnel working on hazardous batteries shall complete EHS0570 Battery
Safety.

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14.3 Hazards

14.3.1 Electrical Hazards. Electrical safety during battery operations is primarily

concerned with prevention of a direct short circuit across one or more cells. Due
to the large amount of stored energy in the battery cells, along with the low
internal resistance of the cells, a short circuit could have catastrophic results
including an explosion of the cells involved.

14.3.2 Chemical Hazards

a. For each battery type considered for use, obtain Material Safety Data Sheet
(MSDS) information and understand the specific hazards involved before use.

b. Chemicals associated with battery systems may include:

 Cadmium (Cd);
 Lead (Pb);
 Lead peroxide (PbO2);
 Lithium hydroxide (LiOH);
 Lithium Hexafluorophosphate (LiPF6) in propylene/ethylene carbonate
(Flammable)
 Potassium hydroxide (KOH);
 Sodium bicarbonate (NaHCO3);
 Sodium hydroxide (NaOH); and
 Sulfuric acid (H2SO4).

c. Many of these chemicals (and other battery components not listed here) are
corrosive, poisonous and/or flammable. Possible consequences of a ruptured
container or spilled electrolyte include:
 Fire;
 Explosion;
 Chemical burns; and
 Reactions to toxic fumes, solids or liquids.

14.4 Operation and Maintenance

Page 209 of 217

14.4.1 Personnel conducting electrical work on battery systems are to follow the following
guidelines:

a. Use insulated tools in accordance with 18.1. Insulated tools should be stored
in a manner that will not expose them to degradation from battery chemicals.

b. Only instruments having a non-conductive case (e.g., the yellow rubber holster
provided with some multimeters) are permitted in the vicinity of battery
systems.

c. Storage battery systems may present terminal voltages of 48, 125 or 250 V
DC. If the physical construction of the battery system permits, inter-cell or
inter-tier cables should be disconnected

Page 210 of 217

 when performing work on the battery system. See Fig. 14.4.1. The idea behind
splitting the intercell ties in this manner is to reduce the exposed voltage in the
fewest number of steps, thereby minimizing the exposure to energized parts.

d. If one terminal of the battery system is bonded to ground, an additional hazard

exists. Single-point contact between an exposed battery terminal and
surrounding structures could result in very large short-circuit currents and
possibly lead to fires or personal injury.

14.4.2 Take care to not overcharge or exposing rechargeable batteries to higher voltages
than recommended. Use of wrong charger can cause failure and possible
explosion.

14.4.3 Operation and maintenance of automated battery test equipment must be

performed in accordance with manufacturer's instructions. Refer to the
manufacturer's operation manual for specific precautions. Ensure that the
equipment is placed in an Electrically Safe Work Condition when performing
maintenance inside the battery tester cabinet.

Page 211 of 217

Figure 14.4.1. Example of sectionalizing a large, multi-tier battery system.

Page 212 of 217

15 Capacitors

15.1 Scope

15.1.1 This section covers hazardous capacitors that are used in the following
typical Facilities and R&D applications:

a. Inverters and converters

b. Power filtering

c. Power factor correction

d. Lighting inverters

e. UPS systems

f. Variable Speed Drives (VFD)

g. Magnet power supplies

h. High voltage power supplies

i. Low voltage, high current power supplies

15.2 Qualification & Training

15.2.1 Only Qualified Electrical Workers may perform work on capacitors that exceed the
shock thresholds of
2.2.13 (10 Joules or greater and 100 Volts or greater).

15.2.2 Qualified Electrical Workers who perform work on high-hazard capacitors shall
complete EHS0571,
QEW Capacitor Safety.

15.2.3 For capacitors below the shock thresholds of 2.2.13, training class EHS057X, Non-
QEW Capacitor Safety
Page 213 of 217
 is required when:

a. 100-400 V: if the stored energy is 1 – 10 J

b. >400 V: if the stored energy is 0.25 – 10 J

15.3 Hazards

15.3.1 Shock hazard:

a. The shock hazard to a person is an impulse shock hazard limited by the

discharge time constant. For voltages less than 100 V, there is no shock hazard.
For voltages between 100-400 V, the discharge is

Page 214 of 217

 significantly limited by a long time constant, related to skin surface resistance.
Above 400 V, the skin ruptures and the time constant is limited by internal
body resistance alone.

b. For voltages above 100 V, safety margins assume only an internal body
resistance of 1000 Ohms. The time constant, , is equal to resistance times
capacitance (=RC). The discharge time through the body is assumed to be
three times the time constant.

c. At 10 Joules or greater, there is a significant shock and fibrillation hazard.

d. Below 10 Joules, a significant reflex action may occur and cause injury:
 100-400 V: if the stored energy is 1 – 10 J
 >400 V: if the stored energy is 0.25 – 10 J

e. Capacitor cases are not always grounded and should be considered

charged unless otherwise determined.

f. Hazardous capacitors may store and accumulate a dangerous residual charge

after the equipment has been de-energized. Grounding capacitors in series may
transfer rather than discharge the stored energy.

g. Because of the phenomenon of "dielectric absorption," not all the charge in a

capacitor is dissipated when it is short-circuited for a short time. High voltage
capacitors may build a charge in the presence of high electric fields.

h. A hazardous voltage can exist at the moment of contact across the

impedance of a few feet of grounding cable at the moment of contact with
a charged capacitor.

15.3.2 Short-circuit hazard

a. Capacitors have the unique ability to discharge very rapidly in a shorted

condition. AC power system faults typically occur on the order of milliseconds
and are limited by transformer impedances. Battery faults take seconds or
Page 215 of 217
 minutes to discharge. Capacitors can fully discharge in microseconds, with
very high current.

b. At around 100 J, a short through a ring or tool can cause rapid heating and
burns to the skin. Above 1 kJ, there can be substantial heating of metal, arcing
and magnetic forces causing mechanical deformation. Above 10 kJ, there is
massive conductor melting, massive magnetic/mechanical motion, and an
explosion hazard.

15.3.3 Arc Flash Hazard

a. An arc flash hazard may exist at high energy levels (>10 kJ).

b. Calculate the capacitor arc flash boundary as follows:

Page 216 of 217

𝐴𝐹𝐵 = √0.05 ∗ 𝐸

where AFB = Arc Flash

Boundary in cm E =

Capacitive stored energy in

Joules

Note: it takes about 40 kJ to cause an Arc Flash Boundary of 18 inches.

c. For capacitors >10 kJ, contact the ESO for an arc flash hazard analysis and PPE
selection.

15.3.4 Explosion hazard

a. An additional hazard exists when a capacitor is subjected to high currents

that may cause heating and explosion.

b. When capacitors are used to store large amounts of energy, internal failure of
one capacitor in a bank frequently results in explosion when all other
capacitors in the bank discharge into the fault.

c. Fuses are generally used to preclude the discharge of energy from a capacitor
bank into a faulted individual capacitor. Improperly sized fuses for this
application may explode.

15.3.5 Other hazards

a. The liquid dielectric and combustion products of liquid dielectric in capacitors may
be toxic.

b. Discharging a capacitor by means of a grounding hook can cause a loud

electric arc at the point of contact. Above 100 Joules, hearing protection is
required for hard grounding. Above 1000, soft grounding is required.
Page 217 of 217
 15.3.6 Internal faults may rupture capacitor containers. Rupture of a capacitor can
create a fire hazard. Dielectric fluids may release toxic gases when
decomposed by fire or the heat of an electric arc.

15.4 Stored Energy Hazard Assessment

15.4.1 The stored energy in a capacitor is calculated as follows:

𝐸= 𝐶. 𝑉2
1
2
where E = Capacitive stored

energy in Joules C = Total

capacitance in Farads

V = Peak voltage in Volts

Page 218 of 217

 15.4.2 Total capacitance of capacitor banks:

𝐶𝑡𝑜𝑡𝑎𝑙 = 𝐶1 + 𝐶2 + 𝐶3 + ⋯
a. For capacitors in parallel, add the capacitance:

+⋯
1 1 b. 1For capacitors
1 in series, use the following:

𝐶𝑡𝑜𝑡𝑎𝑙 � � 𝐶3
= + +
� 1 �2

or

𝐶𝑡𝑜𝑡𝑎𝑙 𝐶 1. 𝐶 2. 𝐶 3. …
= 𝐶1 + 𝐶2 + 𝐶3 + …

15.4.3 For peak voltage, always use the voltage applied across the capacitors that would
cause the maximum charge. For disconnected capacitors in storage or for
disposal, use the capacitor rated voltage.

15.4.4 DC systems: Use the maximum available pole-to-pole voltage that could be
applied to the capacitor by the system.

15.4.5 AC systems: Nominal system voltage is normally expressed in Volts rms

(root mean square). For capacitor stored energy calculations, use the peak

𝑉 = 𝑉 = 0.707 𝑉
√2 amplitude of the voltage, Vp.
𝑟𝑚𝑠 2 𝑝 𝑝

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 𝑉𝑟𝑚𝑠 𝑉𝑟𝑚𝑠
𝑝𝑉
a. Single phase AC systems: use peak AC voltage.
= = 0.707
√2
2

Page 220 of 217

 Example: A single phase 120 VAC motor with a starting capacitor:

𝑉𝑟𝑚𝑠
120= = = 170 𝑉 𝑎𝑐𝑟𝑜𝑠𝑠 𝑡ℎ𝑒 𝑐𝑎𝑝𝑎𝑐𝑐𝑐𝑡𝑜𝑟
𝑝
√2 0.707
2

𝑉𝜙𝜙−𝑁 𝑉𝜙𝜙−𝑁
b. For 3-phase Wye-connected systems, use the peak phase-to-neutral AC voltage.
𝑝𝑉 = = 0.707
√2
2

Example: A 480 V wye-connected system with power factor correction capacitors:

𝑉𝜙𝜙−𝑁
𝑉 = = 392 𝑉 𝑎𝑐𝑟𝑜𝑠𝑠 𝑡ℎ𝑒 𝑐𝑎𝑝𝑎𝑐𝑐𝑐𝑡𝑜𝑟𝑠
=
277

𝑝
0.707 0.707

c. For 3-phase Delta-connected systems, use the peak phase-to-phase AC voltage.

𝑉𝜙𝜙−𝜙𝜙 𝑉𝜙𝜙−𝜙𝜙
𝑐𝑎𝑝𝑉 = = 0.707
√2
2
Example: A 480 V delta-connected system with power factor correction capacitors:

𝑉𝜙𝜙−𝜙𝜙
𝑉 = = 679 𝑉 𝑎𝑐𝑟𝑜𝑠𝑠 𝑡ℎ𝑒 𝑐𝑎𝑝𝑎𝑐𝑐𝑐𝑡𝑜𝑟𝑠
=
480

𝑝
0.707 0.707

Note: for the same capacitance, a delta-connected system will have a total energy
3 times higher than a wye-connected system. Always check the configuration as
design requirements vary.
Page 221 of 217
 d. Capacitor banks used for power factor correction are often labeled with a
kVAR value (kilo Volt- Amps Reactive) to facilitate power engineering
calculations. Calculate the capacitance as follows:

𝑄𝑄
𝐶=
2𝜋𝜋𝜋𝑉2

Where C= Total capacitance in Farads

Q = Reactive power in VAR (Volt

Amps Reactive) f = frequency in

Hertz

V = Phase-to-phase voltage in Volts

Page 222 of 217

15.4.6 High voltage coaxial cables can store capacitive energy. Look up the
manufacturer’s datasheet on capacitance per foot and use the maximum available
output voltage of the power supply. It is normally on the order of 15-35 pF/ft.

15.4.7 More Examples

a. An HVAC compressor has a single phase 120 V motor with a 149 µF starting
capacitor in parallel with a 6 µF running capacitor.

The total capacitance is: 𝐶𝑡𝑜𝑡𝑎𝑙 = 𝐶𝑠𝑡𝑎𝑟𝑡 + 𝐶𝑟𝑢𝑛 = 149 + 6 = 155 µF

The stored energy is: 𝐸 = 1 𝐶. 𝑉2 = 0.5 ∗ 155 ∗

= 2.23 𝐽
10 ∗ �
2 0.70
�
−6 120
2

Page 223 of 217

 b. A facilities distribution power factor correction cabinet is delta-connected and
labeled as follows:

In this case, Q = 375,000 VAR, f = 60 Hz and V = 480 V. Therefore,

𝑄𝑄
𝐶=
= 2𝜋. 60. = 4.3 𝑚𝐹
375,000
2𝜋𝜋𝜋𝑉2
4802

and 𝐸 = 1 𝐶. 𝑉2 = 0.5 ∗ 4.3 ∗ 10−3 ∗ �

2
= 991 𝐽
480

0.707�

Page 224 of 217

Page 225 of 217
 c. A Glassman Power Supply is used to provide 10-12 kVDC to a vacuum
chamber and uses 25 feet of 40 kV, 20 AWG coaxial cable. The cable has a
capacitance of 26 pF/foot at 1 kHz. The power supply can provide up to 30

𝐶 = 25 𝜋𝜋𝑒𝑒𝑡 ∗
kV and has an internal stored energy of 1.8 J.
𝑝𝐹 = 650 𝑝𝐹
𝜋𝜋𝑜𝑜𝑡
26

𝐸 = 1.8 + = 1.8 + ∗ 650−1 ∗

1
= 2.09 𝐽𝑜𝑢𝑙𝑒𝑠
1
𝐶. 𝑉2 2
∗ 10 2 2 30000 2

d. An X-ray machine1 uses a 60 kV power supply and has 6 nF of capacitance.

2 1 −9 2

𝐸 = 𝐶. 𝑉 = ∗ 6 ∗ 10 = 10.8 𝐽𝑜𝑢𝑙𝑒𝑠
2 2 ∗
60000

Page 226 of 217

Page 227 of 217
 15.5 Capacitor Discharge Time

V. It is related to the time constant 𝑟.

15.5.1 The discharge time Td of a capacitor is the time it takes to reduce to less than 50

𝑟 = 𝑅𝐶

𝑇𝑑 �𝑟
50
𝑉𝑝
= �
−ln

where  = time constant

R = discharge path

resistance C = total

capacitance

Td = discharge time

(wait time) Vp = Peak

voltage

15.5.2 For bleed resistors, the resistance is normally selected to discharge the voltage to
less than 50 V within an acceptable discharge time. This is true for both installed
bleed resistors and for a soft-grounding device.

15.5.3 The power rating of the discharge resistor also should be more than the initial
discharge power:
𝑉 𝑝2
𝑄𝑄𝑑 =
𝑅

where Qd = Initial

Page 228 of 217

 discharge power R =

discharge path resistance

Vp = Peak voltage

discharge time. That is because after 3 𝑟, the residual voltage is less than 5% of
15.5.4 For voltages below 1000 V, it is common to use 3 time constants as the standard

longer than 3 𝑟.
the initial voltage. For voltages above 1000 V, the discharge time will need to be

Page 229 of 217

Fig. 15.5.4 – Exponential charge decay curve for an RC bleed network after line voltage is
removed.  is the time constant. After 3, the capacitor voltage is less than 5% of the
original voltage.

Fig. 15.6.1 – Example of a capacitor stored energy warning label

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15.6 Capacitor Hazard Labeling

15.6.1 Electrical equipment containing capacitive stored energy 10 Joules or greater

must be field marked with a label containing all the following information:

a. A warning about the potential for capacitive stored energy, with the word
“WARNING” on an orange colored background.

b. Stored energy in Joules

c. Wait time before opening enclosure

d. Date of the stored energy hazard analysis

e. An instruction to use a Complex LOTO Procedure

15.6.2 Labeling must conform to the requirements of ANSI Z535.

15.6.3 Where the stored energy exceeds 10,000 J, the signal word “DANGER” on a
red colored background must be used instead.

15.6.4 Where the stored energy is less than 10 J but above the thresholds of 15.2.3,
labeling is not required. If desired the label must use the signal word
“CAUTION” on a yellow background.

15.6.5 Caution should be used with regards to the placement of fuses and automatic
discharge safety devices. If the discharge flows through the fuses, a prominent
warning sign should be placed at each entry indicating that each capacitor should
be manually grounded before work can begin.

15.7 Hard Grounding vs Soft Grounding

15.7.1 Hard grounding is the practice of shorting a capacitor directly to ground. Since the
resistance is typically
<0.1 Ohm, the discharge time is very rapid. A loud spark and bang can happen
at higher voltage and energies. Above 100 Joules there is a hearing damage
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 hazard.

15.7.2 Soft grounding is the practice of connecting a capacitor to ground through a

power resistor. The resistor raises the time constant (=RC) and reduces the
peak discharge current (I= V/R) to safer levels. Soft grounding is required above
1000 Joules.

15.7.3 At the conclusion of the specified discharge time, there is still voltage on the
capacitors. A properly matched resistor and capacitor will reduce the voltage to
less than 50 V and the energy to less than 5 Joules. At this point hard grounding
is applied to fully short the capacitors to ground.

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15.7.4 Sometimes the grounding resistor is attached directly to the grounding stick.
Other times, there are two separate grounding points. The grounding point
labeled “Hi-Z” is the soft grounding point, where “Hi-Z” stands for High
Impedance. In this case the same ground stick is applied, first to the Hi-Z point,
then to the ground point.

15.7.5 All ground sticks must meet the requirements of 18.4.

15.8 Establishing an Electrically Safe Work Condition (Mode 1)

15.8.1 Where the stored capacitive energy is above the shock thresholds of 2.2.13 (10
Joules or greater and 100 V or greater), a Complex LOTO Procedure shall be
required in accordance with the ES&H Manual, Chapter 18, Lockout/Tagout
Program. The Complex LOTO Procedure shall incorporate the following:

a. Energy in Joules

b. Specific steps to safely discharge the capacitor, or verify that it is discharged

c. Specific tool to ground the capacitors, if required.

15.8.2 Capacitors with bleed resistors, <1000 V

a. Capacitors with a stored energy of 10 Joules or greater should have bleed

resistors installed as part of the design. However, these resistors sometimes
fail and shall not be relied upon to verify zero voltage.

b. After isolating the power supply to a capacitor bank, wait the specified time
for the bleed resistors to discharge the capacitors. By design, this is typically
1 minute or 5 minutes, but may be different depending on the application.
Where a visual voltage indicator is present, observe that it indicates that a safe
voltage has been achieved.

c. After the specified time has elapsed, open the enclosure to access the
capacitors. Use proper PPE and safe work practices for shock and arc flash
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 protection.

d. Using a properly rated volt meter, verify absence of voltage on the

capacitors. Test each pole or phase to ground and between each pole or
phase.

e. If there is residual voltage >50 V, proceed to 15.8.4.b.

15.8.3 Capacitors with bleed resistors, >1000 V

a. After isolating the power supply to a capacitor bank, wait the specified time
for the bleed resistors to discharge the capacitors. By design, this is typically
1 minute or 5 minutes, but may be different depending on the application.
Where a visual voltage indicator is present, observe that it indicates that a safe
voltage has been achieved.

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 b. After the specified time has elapsed, open the enclosure to access the
capacitors. Use proper PPE and safe work practices for shock and arc flash
protection.

c. Select a properly rated grounding device. Visually ensure that the ground
end is properly and securely connected to a ground point.

d. Ground the capacitors. Ground each pole or phase.

15.8.4 Capacitors without bleed resistors

a. After isolating the power supply to a capacitor bank, open the enclosure to
access the capacitors. Use proper PPE and safe work practices for shock and
arc flash protection.

b. Select a properly rated grounding device. Visually ensure that the ground
end is properly and securely connected to a ground point.

c. Ground the capacitors. Ground each pole or phase.

15.8.5 Capacitors of 1000 Joules to 10,000 Joules:

a. Capacitors with a stored energy of 1000 Joules or greater require soft grounding
to limit the acoustic hazard.

b. After isolating the power supply to a capacitor bank, wait the specified time
for the bleed resistors to discharge the capacitors. By design, this is typically
1 minute or 5 minutes, but may be different depending on the application.
Where a visual voltage indicator is present, observe that it indicates that a safe
voltage has been achieved.

c. After the specified time has elapsed, open the enclosure to access the
capacitors. Use proper PPE and safe work practices for shock and arc flash
protection.

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 d. Select a ground stick with a power resistor offering a matching discharge time
constant.

e. Soft-Ground the capacitors at each phase or pole, and wait the specified
discharge time. If voltage indicators are present, watch the discharge on the
indicators.

f. Hard-Ground the capacitors to dissipate all residual voltage.

15.8.6 Capacitors greater than 10,000 Joules:

a. Capacitors with a stored energy of 10,000 Joules or greater require remote

soft grounding. This is usually in the form of a “Ross Relay” that can be
visually checked for closure.

b. After isolating the power supply to a capacitor bank, wait the specified time
for the bleed resistors to discharge the capacitors. By design, this is typically
1 minute or 5 minutes, but may be different

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 depending on the application.

c. Visually verify that the Ross Relay has closed into the grounded position.
Where a visual voltage indicator is present, observe that it indicates that a
safe voltage has been achieved.

d. After the specified time has elapsed, open the enclosure to access the
capacitors. Use proper PPE and safe work practices for shock and arc flash
protection.

e. Select a ground stick with a power resistor offering a matching discharge time
constant.

f. Soft-Ground the capacitors at each phase or pole, and wait the specified
discharge time. If voltage indicators are present, watch the discharge on the
indicators.

g. Hard-Ground the capacitors to dissipate all residual voltage.

15.9 Testing capacitors (Mode 2)

15.9.1 Capacitor diagnostics can be performed energized or deenergized. When

performing energized diagnostics (Mode 2 work), follow all requirements of
shock and arc flash protection in accordance with 6.6.

15.9.2 There are no additional requirements for Mode 2 work regarding capacitors.

15.10 Personal Protective Equipment (PPE)

15.10.1 The Minimum PPE for electrical work of 10.1 is required for all capacitors above the
shock thresholds of
2.2.13 (10 J or greater and 100 V or greater).

15.10.2 Hearing protection is required when hard-grounding capacitors greater than 100 J.

15.10.3 Shock protection PPE is required for all parts of the body that enter the
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 Restricted Approach Boundary (See Table 7.3.DC).

a. Shock protection for the hands is not required for hard ground sticks provided
that the hands stay out of the RAB. If the stick is too short, then voltage rated
gloves of the proper voltage rating must be worn.

b. Soft grounding sticks are considered primary shock protection. If they are not
tested and inspected periodically, then tested and inspected voltage-rated
gloves must also be worn to handle the grounding stick. If the stick is too
short, then voltage rated gloves of the proper voltage rating must be worn.

15.10.4 Arc flash PPE may be required for high energy capacitors, greater than 10 kJ.
At a minimum, wear leather gloves and hearing protection in addition to the
Minimum PPE.

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15.11 Storage & Disposal

15.11.1 Any residual charge from capacitors shall be removed by grounding the
terminals before servicing or removal.

15.11.2 All uninstalled capacitors capable of storing 10 J or greater at their rated

voltage must be short- circuited with a conductor of appropriate size.

15.11.3 When an uninstalled capacitor is discovered without a shorting wire attached to

the terminals, it shall be treated as energized and charged to its full rated voltage
until determined otherwise. Contact an ESO to determine the appropriate steps
to safely discharge the capacitor.

15.11.4 A capacitor that develops an internal open circuit may retain substantial charge
internally even though the terminals are short-circuited. Such a capacitor can be
hazardous to transport, because the damaged internal wiring may reconnect and
discharge the capacitor through the short-circuiting wires. Any capacitor that
shows a significant change in capacitance after a fault may have this problem.
Action should be taken to minimize this hazard when it is discovered.

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16 Inductors

16.1 Scope

16.1.1 This section covers inductors as well as electromagnets and coils that are used in
the following typical applications:

a. Energy storage;

b. Inductors used as impedance devices in a pulsed system with capacitors;

c. Electromagnets and coils that produce magnetic fields to guide or confine charged
particles;

d. Inductors used in DC power supplies; and

e. Nuclear Magnetic Resonance, Electron Paramagnetic Resonance, and

Magnetic Susceptibility Systems.

16.2 Hazards
Examples of inductor hazards include:

16.2.1 Overheating due to overloads, insufficient cooling, or failure of the cooling

system could cause damage to the inductor and possible rupture of the cooling
system.

16.2.2 Electromagnets and superconductive magnets may produce large external force
fields that may affect the proper operation of the protective instrumentation and
controls.

16.2.3 Magnetic fields could attract nearby magnetic material, including tools and
surgical implants, causing injury or damage by impact.

16.2.4 Whenever a magnet is suddenly de-energized, production of large eddy currents in

adjacent conductive material can cause excessive heating and hazardous voltages.
This state may cause the release or ejection of magnetic objects.
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16.2.5 The worker should be cognizant of potential health hazards.

16.2.6 Interruption of current in a magnet can cause uncontrolled release of stored

energy. Engineered safety systems may be necessary to safely dissipate stored
energy. Large amounts of stored energy can be released in the event of a
"quench" in a superconducting magnet.

16.2.7 Current measurements in inductive circuits

a. When a current-measuring device is inserted in series with an inductive circuit,

a hazard may occur if the circuit is suddenly opened (a probe falls off or a fuse
opens, for example). Such sudden events can produce an inductive voltage
spike across the unintentional opening of the circuit. These spikes

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 can be many times the magnitude of the nominal voltage of the circuit, and can
cause breakdown of insulation or electric shock to the worker.

b. Current-measuring devices shall not be used in series with inductive circuits,

or if it is necessary to do so, then precautions shall be taken to mitigate the
hazard of electric shock from the voltage spike.

16.3 Design and Construction

The following need to be considered:

16.3.1 Provide sensing devices (temperature, coolant-flow) that are interlocked with the
power source.

16.3.2 Fabricate protective enclosures from materials not adversely affected by external
EM fields. Researchers should consider building a nonferrous barrier designed to
prevent accidental attraction of iron objects and prevent damage to the cryostat.
This is especially important for superconducting magnet systems.

16.3.3 Provide equipment supports and bracing adequate to withstand the forces
generated during fault conditions.

16.3.4 Appropriately ground electrical supply circuits and magnetic cores and
provide adequate fault protection.

16.3.5 Provide means for safely dissipating stored energy when excitation is interrupted or a
fault occurs.

16.3.6 Provide appropriate warning signs to prevent persons with pacemakers or similar
devices from entering areas with fields of greater than 0.001 Tesla.

16.3.7 Personnel exposure to magnetic fields of greater than 0.1 Tesla should be restricted.

16.3.8 When a magnet circuit includes switching devices that may not be able to
interrupt the magnet current and safely dissipate the stored energy, provide a
dump resistor connected directly across the magnet terminals that is sized to limit
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the voltage to a safe level during the discharge and safely dissipate the stored
energy.

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17 Personal Protective Equipment

17.1 Rubber Insulating Gloves

17.1.1 Purpose. Electrical rubber insulating gloves protect personnel from electrical
shock by providing an insulating barrier between equipment/conductors that
could be energized and personnel. Leather protectors are worn over the gloves
to prevent damage to the glove by mechanic abrasion and other means.

17.1.2 Selection.

a. Rubber insulating gloves shall conform to ASTM D120 – Standard

Specification for Rubber Insulating Gloves. Care of rubber insulating
gloves shall conform to ASTM F496 – Standard Specification for In-
Service Care of Insulating Gloves and Sleeves.

b. Rubber insulating gloves are classified by voltage rating. The electrical

properties that correspond to these classes are shown in Table 17.1. The rubber
insulating glove rating shall be selected based on the equipment’s line-to-line or
line-to-ground (whichever is greater) nominal voltage rating.

c. Classifications. There are six classifications of rubber electrical insulating

electrical gloves (voltage rated gloves). Glove selection is based upon the
nominal voltage of the circuit being worked upon. Gloves are clearly marked
and have color-coded labels at the cuff.

17.1.3 Leather Protectors

a. Leather protector gloves (leather protectors) shall conform to ASTM F696 –

Standard Specification for Leather Protectors for Rubber Insulating Gloves
and Mittens.

b. Leather protector gloves shall be worn over the rubber insulating gloves to
prevent mechanical damage. Leather protectors shall be sized so that the
rubber insulating glove is not deformed from its natural shape. A leather
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 protector that is too small will typically be noticed by the feel of wrinkling of
the rubber insulating glove at the fingertips. A leather protector that is too
large will result in further loss of dexterity.

c. The top cuff of the leather protector glove shall be shorter than the top cuff of
the insulating glove by at least the distance specified in Table 17.1. This is to
prevent tracking of the voltage from the leather protector to the arm.

d. Protector gloves that have been used for any other purpose shall not be used
to protect insulating gloves.

e. Protector gloves shall not be used if they have holes, tears, or other defects
that affect their ability to give mechanical protection to the insulating gloves.

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 f. Care should be exercised to keep the protector gloves as free as possible from
oils, greases, chemicals, and other materials that may injure the insulating
gloves. Protector gloves that become contaminated with injurious materials to
the extent that damage may occur to the insulating glove shall not be used as
protector gloves unless they have been thoroughly cleansed of the
contaminating substance.

g. The inner surface of the protector gloves should be inspected for sharp or
pointed objects; this inspection should be made as often as the rubber
gloves are inspected.

ASTM Class Proof Test Max. Use Leather

Class Color Voltage Voltage Protector
AC/DC AC/DC Cuff
Distance (in)
00 Beige 2,500/10,000 500/750 0.
5
0 Red 5,000/20,000 1,000/1,500 0.
5
1 White 10,000/40,000 7,500/11,25 1
0
2 Yellow 20,000/50,000 17,000/25,5 2
00
3 Green 30,000/60,000 26,500/39,7 3
50
4 Orange 40,000/70,000 36,000/54,0 4
00
Table 17.1 – ASTM Class Voltage Ratings

17.1.4 Cloth Glove Liners.

a. Cloth gloves may be worn inside the rubber insulating gloves for warmth in the
winter and to absorb perspiration in the hot weather.

b. Care should be exercised to keep the cloth gloves as free as possible from oils,
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 grease, chemicals, and other materials that may damage the insulating gloves.
Cloth gloves that become contaminated with damaging materials to the extent
that damage may occur to the insulating glove shall not be used and shall be
discarded and replaced.

c. Do not perform any work wearing only cloth liners, as this will cause the
cloth glove to pick up contaminants that are likely damaging to the rubber
insulating glove.

17.1.5 Inspection Before Use

a. Inspection of rubber insulating gloves shall conform to ASTM F1236 – Standard

Guide for Visual

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 Inspection of Electrical Protective Rubber Products.

b. The field care and inspection of electrical insulating gloves, performed by the
Qualified Electrical Worker, is an important requirement in providing
protection from electric shock. Defective or suspected defective gloves and
sleeves shall not be used but returned to the Electrical Safety Group for
inspection and retest.

c. Rubber insulating gloves shall be visually inspected by the wearer for

defects. They shall be inspected over the entire surface and shall be rolled
gently between the hands to expose defects and imbedded materials.
 Inspect glove and sleeve surface areas by gently rolling their entire
outside and inside surface areas between the hands. This technique
requires gently squeezing together the inside surfaces of the glove or
sleeve to bend the outside surface area and create sufficient stress to
inside surfaces of the glove or sleeve to highlight cracks, cuts, or other
irregularities.
 When the entire outside surface area has been inspected in this manner,
turn the glove or sleeve inside-out and repeat the inspection on the
inside surface (now on the outside).
 If necessary, a more careful inspection of suspicious areas can be
achieved by gently pinching and rolling the rubber between the fingers.
 Pay special attention to the working area of the glove (Fig. 17.1.5). This
includes all finger and thumb crotches, the palm (area between the wrist
and the base of the finger and thumb) and the area of the finger and thumb
facing the palm not extending beyond the centerline of the crotch. This is
essentially the area of surface contact if a person were to firmly grasp a
section of conduit.
 Never leave a glove in an inside-out condition.

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  Stretch the thumb and finger crotches by pulling apart adjacent thumb and
fingers to look for irregularities in those areas.

Fig. 17.1.5 – Working area of Rubber Insulating Glove

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d. Gloves shall be air-tested before use each day and at other times if there is
cause to suspect any damage. The glove shall be examined for punctures and
other defects. Puncture detection may be enhanced by listening for escaping
air or holding the gloves against the worker’s cheek to feel for escaping air.
 Punctures and other small holes in rubber insulating gloves can be found
by inflating the gloves with air pressure. Gloves can be inflated manually
by grasping the side edges of the glove opening and stretching gently,
side-by-side, to close and slightly seal the open end. Roll up the gauntlet
end about 1.5 in. toward the palm by twirling the glove in a rotating
motion using the rolled edges of the glove opening as an axis. Grasp the
rolled up end in one hand to contain the entrapped air in the palm and
fingers. Hold the inflated glove close to one ear and, with the free hand,
squeeze the glove palm to increase the air pressure while listening and
feeling for pinhole leaks. Release the entrapped air.
 To entrap air in heavy weight gloves, it may be necessary to lay the
glove on a flat surface, palm up, and press the open end closed with the
fingers. While holding the end closed, tightly roll up about 1.5 in. of
the gauntlet. Grasp the rolled-up end and inspect for small holes.
 Mechanical glove inflators may also be used to inspect the surface areas
of the products. Take care not to over inflate the gloves, since their
physical characteristics may be adversely affected by over inflating. Type
1 gloves shall not be inflated or stretched to more than twice their normal
size. Type 2 (ozone-resistant) gloves shall not be inflated or stretched to
more than 1.25 times their normal size.

e. Lighting. The visual inspection of electrical protective rubber products requires

good lighting and the products should be thoroughly cleaned before inspection.
The light source should be at least 200 fc with a reflector and should be
adjustable for different lighting conditions. Some irregularities can be more
easily seen with the light shining down on the surface being examined; other
irregularities require a low angle of light to allow the defect to cast a shadow in
order to be seen.

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f. Gloves and sleeves shall be wiped clean of any oil, grease, or other damaging
substances as soon as practicable. Gloves and sleeves should be rinsed as
necessary to remove perspiration. Excess water should be removed by being
shaken out and the article then air dried.

g. Defective rubber insulating gloves shall not be used and shall be removed from
service immediately. If a rubber insulating glove is found to be defective, then
one of the fingers of the glove shall be cut off. The glove pair shall be
exchanged for a new set.

h. The inner surface of the leather protector gloves should be checked for sharp
pointed objects. This inspection should be made as often as the rubber
insulating gloves are inspected.

i. Leather protector gloves shall not be used if they have holes, tears, or other
defects that affect their ability to give mechanical protection to the rubber
insulating glove.

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17.1.6 Storage

a. Rubber insulating gloves that have been issued to a Qualified Electrical

Worker are considered to be “in service”.

b. Gloves and sleeves shall be stored in a location as cool, dark, and dry as
possible. The location shall be as free as practicable from ozone, chemicals,
oils, solvents, damaging vapors and fumes, and away from electrical
discharges and sunlight.

c. Gloves shall be stored in their natural shape. Gloves may be kept inside of
protectors or in a bag, box, or container that is designed for and used
exclusively for them.

a. Gloves and sleeves shall not be stored folded, creased, inside out,
compressed, or in any manner that will cause stretching or compression.

b. When stored hanging inside a canvas glove bag, rubber insulating gloves shall be
kept cuff-down.

c. Clean rubber insulating gloves only with lukewarm water and mild soap
detergent. Do not use solvents, oils, or grease on rubber gloves.

d. Talcum powder or baby powder may not be used inside the rubber insulating
gloves. Only the following powder is approved for use with rubber insulating
gloves: Salisbury Ten-Four® Glove Dust

e. Do not apply any markings to the rubber insulating glove, whether with

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 permanent markers, paint pens or stamps. Only the test stamp applied by the
certified testing laboratory is permitted.

17.1.7 6-Month Testing

a. Periodic testing of rubber insulating gloves shall conform to ASTM F 496,

Standard Specification for In-Service Care of Insulating Gloves and Sleeves.
The glove testing program is managed by the Electrical Safety Group.

b. Rubber insulating gloves shall be tested prior to being issued. A test date
will be stamped or permanently marked on the cuff of the glove.

c. Rubber insulating gloves shall be exchanged every 6 months after issue. It is

acceptable to retest

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 gloves and return them to service or to replace the gloves with new gloves.

d. The shelf life of tested gloves in storage is 12 months. Gloves may be issued
at any time during the 12 months. The issue date triggers a 6-month time
period, at the end of which the gloves must be returned and exchanged.

17.2 Rubber Insulating Blankets

17.2.1 Rubber insulating blankets may be used to provide primary shock protection
when work is being performed adjacent to exposed, energized parts (7.3.3.c).
Blankets shall conform to ASTM D1048 - Standard Specification for Rubber
Insulating Blankets.

17.2.2 Rubber insulating blankets are designed to be reusable and are subject to
periodic inspection and testing requirements similar to voltage gloves.

17.2.3 Rubber insulating blankets are typically available in all ASTM classes per table 17.1.

17.2.4 Inspection of rubber insulating blankets shall conform to ASTM F1236 –

Standard Guide for Visual Inspection of Electrical Protective Rubber
Products. Defective blankets shall not be used and shall be removed from
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service.

a. Place rubber blankets on a clean, flat surface and roll up tightly starting at
one corner and rolling toward the diagonally opposite corner.

b. Inspect the entire surface for irregularities as it is rolled up. Unroll the blanket
and roll it up again at right angles to the original direction of rolling.

c. Repeat the rolling operations on the reverse side of the blanket.

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17.2.5 Care of Blankets - Blankets shall be stored in a cool, dark, and dry location free
from ozone, chemicals, oils, solvents, damaging vapors and fumes, and away
from electrical discharges. Blankets shall be stored in a container that is designed
for and used exclusively for them and shall not be kept folded, creased, distorted,
or compressed in any manner that will cause stretching or compression.

17.2.6 Blankets shall be cleaned as necessary to remove foreign substances and shall
be wiped clean of any oil, grease or other damaging substances as soon as
practicable. Clean only with lukewarm water and mild soap detergent. Rinse
thoroughly with water to remove all of the soap or detergent.

17.2.7 Do not apply any markings to the blanket, whether with permanent markers,
paint pens or stamps. Only the test stamp applied by the certified testing
laboratory is permitted.

17.2.8 Testing

a. Periodic testing of rubber insulating blankets shall conform to ASTM F 479,

Standard Specification for In-Service Care of Insulating Blankets. The
blanket testing program is managed by the Electrical Safety Group.

b. Rubber insulating blankets shall be tested prior to being issued. A test date
will be stamped or permanently marked on the blanket.

c. Rubber insulating blankets shall be exchanged every 12 months after issue. It

is acceptable to retest blankets and return them to service or to replace the
blankets with new blankets.

d. The shelf life of tested blankets in storage is 12 months. Blankets may be

issued at any time during the 12 months. The issue date triggers a 12-month
time period, at the end of which the blankets must be returned and exchanged.

17.3 Rubber Insulating Sheeting

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17.3.1 Rubber insulating sheeting may be used to provide primary shock protection
when work is being performed adjacent to exposed, energized parts (7.3.3.c).
Rubber insulating sheeting shall conform to ASTM F2320 - Standard
Specification for Rubber Insulating Sheeting.

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17.3.2 Rubber insulating sheeting is designed to be disposable. Precut sections may
be reused but shall be discarded no more than 6 months after being cut from
the parent roll.

17.3.3 Rubber insulating sheeting is available in all ASTM classes per table 17.1.

17.4 PVC Insulating Sheeting

17.4.1 PVC (Poly Vinyl Chloride) insulating sheeting may be used to provide primary
shock protection when work is being performed adjacent to exposed, energized
parts (7.3.3.c). PVC insulating sheeting shall conform to ASTM D1742 –
Standard Specification for PVC Insulating Sheeting.

17.4.2 PVC insulating sheeting is designed to be disposable. Precut sections may

be reused but shall be discarded no more than 6 months after being cut from
the parent roll.

17.4.3 PVC insulating sheeting is typically available in ASTM classes 0 and 1 per table
17.1.

17.4.4 The primary advantage of PVC insulating sheeting over rubber insulating is that it is
clear.

17.5 Arc-Rated PPE

17.5.1 Types of materials:

a. Arc-rated: any item meeting the requirements of ASTM F 1506, Standard

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 Performance Specification for Flame Resistant and Arc Rated Textile
Materials for Wearing Apparel for Use by Electrical Workers Exposed to
Momentary Electric Arc and Related Thermal Hazards

b. Flammable: any item that does not meet the requirements of ASTM F 1506.

c. Melting: materials consisting of fabrics, zipper tapes, and findings made from
flammable synthetic materials that melt at temperatures below 315°C (600°F),
such as acetate, acrylic, nylon, polyester, polyethylene, polypropylene, and
spandex, either alone or in blends, are considered melting, unless they meet the
requirements of ASTM F 1506. These materials melt as a result of arc flash
exposure conditions, form intimate contact with the skin, and aggravate the
burn injury.

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17.5.2 All arc-rated PPE shall conform to the requirements of ASTM F 1506, Standard
Performance Specification for Flame Resistant and Arc Rated Textile Materials
for Wearing Apparel for Use by Electrical Workers Exposed to Momentary
Electric Arc and Related Thermal Hazards. Conformance shall be indicated by a
tag or label on the garment. The tag or label shall also indicate the ATPV rating of
the garment.

17.5.3 Clothing and Other Apparel Not Permitted. Clothing and other apparel (such as
hard hat liners and hair nets) made from melting materials or made from
materials that do not meet the flammability requirements shall not be permitted to
be worn.

17.5.4 Layering. Non-melting, flammable fiber garments shall be permitted to be used

as underlayers in conjunction with arc-rated garments in a layered system for
added protection. If nonmelting, flammable fiber garments are used as
underlayers, the system arc rating shall be sufficient to prevent breakopen of the
innermost arc-rated layer at the expected arc exposure incident energy level to
prevent ignition of flammable underlayers. Garments that are not arc-rated shall
not be permitted to be used to increase the arc rating of a garment or of a
clothing system.

17.5.5 Outer Layers. Garments worn as outer layers over arc-rated clothing, such as
jackets or rainwear, shall also be made from arc-rated material.

17.5.6 Underlayers. Meltable fibers such as acetate, nylon, polyester, polypropylene, and
spandex shall not be permitted in fabric underlayers (underwear) next to the skin.

a. Exception: An incidental amount of elastic used on non-melting fabric

underwear or socks shall be permitted.

17.5.7 Coverage. Clothing shall cover potentially exposed areas as completely as

possible. Shirtsleeves shall be fastened at the wrists, and shirts and jackets shall
be closed at the neck. Arc-rated clothing shall cover associated parts of the body
as well as all flammable apparel while allowing movement and visibility.
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17.5.8 Fit. Tight-fitting clothing shall be avoided. Loose-fitting clothing provides
additional thermal insulation because of air spaces. Arc-rated apparel shall fit
properly such that it does not interfere with the work task.

17.5.9 Interference. The garment selected shall result in the least interference with the
task but still provide the necessary protection. The work method, location, and
task could influence the protective equipment selected.

17.5.10 Clothing and Other Apparel Not Permitted. Clothing consisting of fabrics, zipper
tapes, and findings made from flammable synthetic materials that melt at
temperatures below 315°C (600°F), such as acetate, acrylic, nylon, polyester,
polyethylene, polypropylene, and spandex, either alone or in blends, are
considered melting and shall not be used unless incorporated in materials that
meet the requirements of ASTM F 1506. Clothing and other apparel (such as
hard hat liners and hair nets) made

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 from melting materials or made from materials that do not meet the
flammability requirements shall not be permitted to be worn.

17.5.11 Where the work to be performed inside the arc flash boundary exposes the worker
to multiple hazards, such as airborne contaminants, under special permission by
the Electrical AHJ for Safe Work Practices and where it can be shown that the
level of protection is adequate to address the arc flash hazard, non- arc-rated PPE
shall be permitted.

a. Work in clean rooms necessitates wearing gear that is not arc-rated. Arc-rated
clean room suits are available up to 4 cal/cm2. Contact the Electrical Safety
Group for more information. For exposures above 4 cal/cm2, there is no PPE
that meets the requirements of clean rooms and arc flash protection. Clean
rooms should be designed to limit arc flash exposure to less than 4 cal/cm2.

17.5.12 Arc-rated face shields and flash suit hoods

a. Face shields shall have an arc rating suitable for the arc flash exposure. Face
shields without an arc rating shall not be used.

b. Face shields shall not be worn for exposures of greater than 12 cal/cm 2. An
arc-rated hood shall be used instead.

c. Face shields shall be worn with an arc-rated balaclava for an exposure range of
above 1.2 cal/cm2 to 12 cal/cm2.

d. Face shields shall include a wraparound guarding to protect the face, chin,
forehead, ears, and neck area.

e. Eye protection (safety glasses or goggles) shall always be worn under face shields
and hoods.

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Fig. 17.5.12 – Arc-Rated Face Shield, Balaclava and Hood

17.5.13 Care and maintenance of Arc-Rated PPE

a. Inspection. Arc-rated apparel shall be inspected before each use. Work

clothing or arc flash suits that are contaminated, or damaged to the extent that
their protective qualities are impaired, shall not be used. Protective items that
become contaminated with grease, oil, or flammable liquids or combustible
materials shall not be used.

b. Manufacturer’s Instructions. The garment manufacturer’s instructions for care

and maintenance of arc-rated apparel shall be followed.

c. Storage. Arc-rated apparel shall be stored in a manner that prevents physical

damage; damage from moisture, dust, or other deteriorating agents; or
contamination from flammable or combustible materials.

d. Cleaning, Repairing, and Affixing Items. When arc-rated clothing is cleaned,

manufacturer’s instructions shall be followed to avoid loss of protection.
When arc-rated clothing is repaired, the same arc-rated materials used to
manufacture the arc-rated clothing shall be used to provide repairs.
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17.6 Other PPE

17.6.1 Hard hats shall conform to ANSI Z89.1, Personal Protection – Protective
Headwear for Industrial Workers. Hard hats shall be of Class E (Electrical, tested
to 20 kV) or G (General, tested to 2.2 kV). Class C (Conductive) hard hats are
not permitted. Note that QEW 3 workers should only wear Class E hard hats, and
that fiberglass hard hats are typically Class G.

17.6.2 Safety glasses shall conform to ANSI Z87.1, Practice for Occupational and
Educational Eye and Face Protection. Safety glasses shall not be of the
wireframe type.

17.6.3 Hearing protection shall consist of ear canal inserts and shall have a minimum
Noise Reduction Ratio (NRR) of 20 dB. Non arc-rated earmuffs are acceptable
provided they are worn under the balaclava of arc flash hood. Arc-rated
earmuffs are also acceptable.

17.6.4 Leather gloves used for non-hazardous switching are not required to follow a
standard.

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18 Electrical Tools & Equipment

18.1 Testing Equipment

18.1.1 Measurement Category

a. The measurement category is a classification system in UL 61010-2 for rating

the transient overvoltage capability of testing and measuring instruments
according to the type of mains circuits to which they are intended to be
connected. Measurement categories take into account overvoltage categories,
short-circuit current levels, the location in the building installation at which the
test or measurement is to be made, and some forms of energy limitation or
transient protection included in the building installation.

b. Testing equipment used on premises wiring systems (including panel boards

and service disconnects) rated at less than 600 VAC shall at a minimum be
rated to Measurement Category IV (CAT IV) at 600 VAC.

c. Testing equipment used on utilization equipment rated at 277/480 VAC shall at

a minimum be rated to Measurement Category III (CAT III) at 600 VAC.

d. Testing equipment used on utilization equipment rated at 250 VAC or less

shall at a minimum be rated to Measurement Category II (CAT II) at 300
VAC.

e. All probes and probe leads shall be rated at least to the same
Measurement Category as that required for the meter.

18.1.2 Voltage Testers

a. Voltage testers shall be listed to UL 61010-2-033, Standard for Safety,

Safety requirements for electrical equipment for measurement, control, and
laboratory use – Part 2-033: Particular Requirements for Hand-Held
Multimeters and Other Meters, for Domestic and Professional Use,
Capable of Measuring Mains Voltage.
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b. Solenoid type detectors shall not be used at Berkeley Lab. As they are low-
impedance devices, they draw a load current through a magnetic coil and
displace a spring-loaded plunger. They typically have a duty rating, meaning
they can only be applied to a live circuit for a limited amount of time.
Although a clear favorite for electricians in the past, experience has shown that
these devices have higher failure rates than high-impedance digital voltmeters.

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18.1.3 Current Testers

a. Only clamp-on style ammeters shall be used for measuring power systems current
(≥ 50 VAC, ≥ 5 A).

b. Clamp-on ammeters shall be listed to UL 61010-2-032, Standard for Safety,

Safety requirements for electrical equipment for measurement, control, and
laboratory use – Part 2-032: Particular Requirements for Hand-Held and
Hand-Manipulated Current Sensors for Electrical Test and Measurement.

18.1.4 All other testing equipment shall be listed to UL 61010-2-030, Standard for
Safety, Safety requirements for electrical equipment for measurement, control,
and laboratory use – Part 2-030: Particular Requirements for testing and
Page 267 of 217
measuring circuits.

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18.2 Insulated Tools

18.2.1 Insulated tools shall meet the requirements of ASTM F 1505, Standard
Specification for Insulated and Insulating Hand Tools. They shall be marked
with the double triangle symbol and “1000 V”.

18.2.2 Insulated tools and equipment shall be inspected prior to each use. The
inspection shall look for damage to the insulation or damage that may limit the
tool from performing its intended function or could increase the potential for an
incident (for example, damaged tip on a screwdriver).

18.3 Insulated Sticks

18.3.1 Fiberglass-reinforced plastic rod and tube used for live-line tools shall meet the
requirements of ASTM F 711, Standard Specification for Fiberglass-Reinforced
Plastic (FRP) Rod and Tube Used in Live Line Tools.

18.3.2 Insulated sticks may use other materials provided that they have been engineered
for the purpose and approved by an ESO.

18.3.3 Insulated sticks used as primary shock protection shall be inspected and tested once
Page 269 of 217
every 2 years.

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18.4 Temporary Personal Protective Grounds for R&D Equipment (Ground Hooks)

18.4.1 A ground hook system places a grounded conductor at the end of the rod
between the operator and the electrical hazard. The low impedance (low Z)
ground hook system is not a live line tool and there will not be a voltage
potential at the end of the ground hook rod. The integrity of the system will be
measured by the performance of the grounding cable.

18.4.2 High Z ground hooks are used in equipment with greater than 1000 joules energy
storage to limit discharge current. Because of this, they may have a voltage
potential at the end of the rod. High Z ground hooks are highly customized and
come with an Engineering Note that record the calculations made to determine
the discharge time of the circuit and the power requirements for the bleed circuit.
The impedance is designed so that voltage must be less than 50V and stored
energy less than 100 J before the low impedance ground hook is applied and the
High Z ground hook removed.

18.4.3 Ground hooks must be constructed in accordance with the LBNL Electrical
Equipment Build Standard, Appendix C, Ground Hook Safety.

18.4.4 Daily Inspection

a. The ground hook must be visually inspected for defects before use each day.
Excessive dirt should be wiped off the ground stick.

b. If any defect or contamination that could adversely affect the insulating

qualities or mechanical integrity of the ground hook is present, the tool shall
be removed from service and examined and tested. Special attention must be
paid to the ground cable, as any fraying or damage could impair the integrity
of the ground on the end of the ground hook.

c. If the defect or contamination exists on the rod the rod must be replaced.

d. If the defect or contamination exists on the cable then the cable must be

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 repaired or replaced and tested before return to service.

18.4.5 Biannual testing (every 2 years)

a. For all ground hooks: The ground hook system must be tested to verify that
impedance is less than
0.1 Ω to ground with the use of a ground bond tester. NOTE: perform this
test annually when it is located outside or under any other adverse
conditions.

b. High-Z ground hooks with resistors:

 The resistor on the High Z ground hook must be measured and
compared to the specified value.

c. All High-Z ground hook insulating rods shall be removed from service to be
recertified to the ASTM F711 standard or as follows:

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  The test method used shall be designed to verify the tool's integrity
along its entire working length and, if the tool is made of fiberglass-
reinforced plastic, its integrity under wet conditions.

18.4.6 The voltage applied during the tests shall be 246,100 volts per meter (75,000
volts per foot) of length for 1 minute if the tool is made of fiberglass, or
equivalent.

18.5 Temporary Personal Protective Grounds for Utilities (Ground Straps)

18.5.1 Temporary personal protective grounds used for the grounding of utility
equipment (ground straps) are designed for three purposes:

a. To dissipate any stored capacitive charge in a line. This is normally a one-time

discharge after initial deenergization.

b. To continually dissipate any induced voltage on a line. Induced voltage from

nearby energized lines will impose an AC current through the grounds.

c. To conduct the full three-phase to ground available fault current until an

upstream overcurrent protective device trips the circuit, while minimizing
voltage drop across the grounds, and without breaking continuity.

18.5.2 Withstanding the full three-phase to ground available fault current imposes
substantial materials and construction requirements on the ground sets. During a
fault, severe magnetic forces will whip the cables around violently. The clamps,
ferrules and connectors must be secure and strong enough not to break free.
Should a clamp or ferrule break free, it can draw an arc and initiate an arc blast.

18.5.3 On utility systems, a fault current will include contribution from stored magnetic
energy sources (transformers and large motors) that adds a momentary DC offset
to the current. This “asymmetrical” contribution can elevate the fault current up
to 2.5 times. For this reason, where the X/R ratio is greater than 1.8, heavy duty
ground sets are required10.

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18.5.4 Ground straps shall meet the requirements of ASTM F 855, Standard
Specifications for Temporary Protective Grounds to Be Used on De-
energized Electric Power Lines and Equipment.

18.5.5 Ground straps shall be rated for the amount of available bolted fault current at the
point of installation. Refer to the short circuit studies for a calculation of available
bolted fault current. This is usually also listed directly next to the available arc
fault current in the arc flash calculation studies.

18.5.6 Visual Inspection

10 For more information, refer to Appendix X.4, Effect of Asymmetrical Currents On

Temporary Protective Grounding Equipment, in ASTM F 855, Standard Specifications for
Temporary Protective Grounds to Be Used on De-energized Electric Power Lines and
Equipment.

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 a. Ground straps shall be inspected for cuts in the protective sheath and damage
to the conductors. Clamps and connector strain relief devices shall be
checked for tightness.

b. These inspections shall be made at intervals thereafter as service conditions

require, but in no case shall the interval exceed 1 year.

18.5.7 Testing

a. At a minimum, ground straps shall be tested once every 3 years.

b. Ground straps that have been repaired or modified shall be tested prior to
being returned to service.

c. Guidance for inspecting and testing ground straps is provided in ASTM F

2249, Standard Specification for In-Service Test Methods for Temporary
Grounding Jumper Assemblies Used on De- Energized Electric Power Lines
and Equipment.

18.5.8 In the event of sustaining a fault current, such as when a set of ground
straps is inadvertently energized, the ground set shall be destroyed and no
longer used.

18.5.9 Grounding and Testing Devices (Ground Carts)

a. Ground carts shall conform to IEEE C37.20.6, Standard for 4.76 kV to 38 kV-
Rated Ground and Test Devices Used in Enclosures.

b. Ground carts shall be stored in a clean and dry area.

c. Ground carts shall be properly inspected before use:

 All insulating surfaces, including but not limited to the primary support
insulation, voltage probes, and isolation barriers, should be clean and
dry.
 All primary and ground disconnect contacts should be clean, with the
Page 275 of 217
 correct contacts in place and properly lubricated.

d. Ground carts shall be periodically maintained and tested in accordance with IEEE
C37.20.6.

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18.6 Other Tools

18.6.1 Fuse or Fuse Holding Equipment. Fuse or fuseholder handling equipment,

insulated for the circuit voltage, shall be used to remove or install a fuse if
the fuse terminals are energized.

18.6.2 Ropes and Handlines. Ropes and handlines used within the limited approach
boundary of exposed energized electrical conductors or circuit parts operating
at 50 volts or more, or used where an electrical hazard exists, shall be
nonconductive.Portable Ladders. Portable ladders shall have nonconductive
side rails if they are used where the employee or ladder could contact exposed
energized electrical conductors or circuit parts operating at 50 volts or more or
where an electrical hazard exists. Nonconductive ladders shall meet the
requirements of ANSI A14.5, American National Standard for Ladders —
Portable Reinforced Plastic — Safety Requirements.

18.6.3 Voltage-Rated Plastic Guard Equipment. Plastic guard equipment for protection
of employees from accidental contact with energized conductors or circuit
parts, or for protection of employees or energized equipment or material from
contact with ground, shall meet the requirements of ASTM F 712, Standard
Test Methods and Specifications for Electrically Insulating Plastic Guard
Equipment for Protection of Workers.

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PART III – DEFINITIONS AND APPENDICES

Page 278 of 217

Acronyms and Abbreviations
Acronym Full Term
A Ampere
AC Alternating Current
AED Automatic External Defibrillator
AHJ Authority Having Jurisdiction
ANSI American National Standards Institute
ARMS Arc Reducing Maintenance Switch
ASTM American Society for Testing and Materials
ATPV Arc Thermal Performance Value
CFR Code of Federal Regulations
COO Chief Operating Officer
DC Direct Current
DOE Department of Energy
EBT Breakthrough Energy
EESP Electrical Equipment Safety Program
EETP Energized Electrical Testing Permit
EEWP Energized Electrical Work Permit
EHS Environment, Health & Safety
ESA Electrical Safety Advocate
ESD Electrostatic Discharge
ESM Electrical Safety Manual
ESO Electrical Safety Officer
ESP Electrical Safety Program
ESWP Electrical Safe Work Procedure
fc Foot-Candle
GFCI Ground Fault Circuit Interrupter
HVAC Heating, Ventilation and Air Conditioning
Hz Hertz
IEEE Institute of Electrical and Electronics Engineers
ISM Integrated Safety Management
J Joule
kHz Kilohertz
kV Kilovolt
LBNL Lawrence Berkeley National Laboratory
LOTO Lockout/Tagout
mA Milliampere
MCC Motor Control Center
MHz Megahertz
NEC National Electrical Code
NFPA National Fire Protection Association
NRTL Nationally Recognized Testing Laboratory

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OEM Original Equipment Manufacturer
OSHA Occupational Safety and Health Administration
PIC Person in Charge
PPE Personal Protective Equipment
PVC Poly Vinyl Chloride
QEW Qualified Electrical Worker
R&D Research & Development
RF Radio Frequency
RPT Relocatable Power Tap
SME Subject Matter Expert
SWD Switching Duty
UL Underwriter’s Laboratories
UPS Uninterruptible Power Supply
V Volt
VAC Volts Alternating Current
VDC Volts Direct Current
W Watts
ZVV Zero Voltage Verification

Source Term Definition

NEC Accessible (as applied Admitting close approach; not guarded by
to locked doors, elevation, or other effective
equipment) means.
NEC Accessible (as Capable of being removed or exposed without
damaging the building structure or finish or not
applied to wiring permanently closed in by the structure or finish
methods) of the building.
NEC Accessible, Capable of being reached quickly for operation,
Readily renewal, or inspections without requiring those
(Readily to whom ready access is requisite to actions
Accessible) such as to use tools, to climb over or
remove obstacles, or to resort to portable
ladders, and so forth.
UL 817 Adapter Cord Set A cord set, without a switch, for use at locations
such as construction sites to provide power from
a single plug to a
maximum of 6 outlets, convert from one
contact configuration to another, or both.
NFPA 70E Approved Acceptable to the authority having jurisdiction
NFPA 70E Arc Flash Hazard A dangerous condition associated with the
possible release of energy caused by an electric
Page 280 of 217
 arc, resulting in second- degree burns to the
skin or ignition of clothing.
NFPA 70E Arc Flash Suit A complete arc-rated clothing and equipment
system that covers the entire body, except for
the hands and feet. An arc flash suit may include
pants or overalls, a jacket or a
coverall, and a beekeeper-type hood fitted
with a face shield.

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NFPA 70E Arc Rating The value attributed to materials that describes
their performance to exposure to an electrical
arc discharge. The arc rating is expressed in
cal/cm2 and is derived from the determined
value of the arc thermal performance value
(ATPV) or energy of breakopen threshold
(EBT) (should a material system exhibit a
breakopen response below the ATPV value).
Arc rating is reported as either ATPV or EBT,
whichever is the lower value.

Arc-rated clothing or equipment indicates that

it has been tested for exposure to an electric
arc. Flame resistant clothing without an arc
rating has not been tested for
exposure to an electric arc. All arc-rated
clothing is also flame-resistant.
ASTM Arc Thermal The incident energy (cal/cm2) on a material or
a multilayer system of materials that results
F1959/F195 Performance Value in a 50% probability that sufficient heat
9M (ATPV) transfer through the tested specimen is
predicted to cause the onset of a second
degree skin burn injury based on the Stoll
curve.
NEC Attachment Plug A male contact device that, by insertion in a
(Plug Cap) (Plug) receptacle, establishes a connection between the
conductors of the
attached flexible cord and the conductors
connected permanently to the receptacle.
NFPA 70E Authority An organization, office, or individual
Having responsible for enforcing the requirements
Jurisdiction of a code or standard, or for
(AHJ) approving equipment, materials, an installation,
or a procedure.
NFPA 70E Automatic Performing a function without the
necessity of human intervention
NFPA 70E Balaclava (Sock Hood) An arc-rated hood that protects the neck and
head except for the facial area of the eyes and
nose.
NFPA 70E Barricade A physical obstruction such as tapes, cones, or
A-frame-type wood or metal structures
intended to provide a warning and to prevent
unauthorized access to a work area.
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NFPA 70E Barrier An insulating physical obstruction, such as
insulating sheeting, an insulating blanket, or a
lexan cover, that is intended to prevent contact
with energized electrical conductors and circuit
parts. Barriers may be permanently
installed in the equipment, or placed temporarily
during performance of energized work.
NEC Bonded (Bonding) Connected to establish electrical continuity and
conductivity.
NEC Bonding A reliable conductor to ensure the required
electrical conductivity between metal parts
Conductor or required to be electrically connected.
Jumper
NFPA 70E Boundary, Arc Flash When an arc flash hazard exists, an approach
limit at a distance from a prospective arc
source within which a person could receive a
second degree burn if an electrical arc flash
were to occur. A second degree burn is
possible by an exposure of unprotected skin to
an electric arc flash
above 2the incident energy level of 5 J/cm2 (1.2
cal/cm ).
NFPA 70E Boundary, An approach limit at a distance from an exposed
energized
Limited electrical conductor or circuit part within which
Approach a shock hazard exists.

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NFPA 70E Boundary, An approach limit at a distance from an exposed
Restricted energized electrical conductor or circuit part
Approach within which there is an increased likelihood of
electric shock, due to electrical arc- over
combined with inadvertent movement, for
personnel working in close proximity to the
energized electrical
conductor or circuit part.
NEC Branch Circuit The circuit conductors between the final
overcurrent device protecting the circuit and the
outlet(s).
NEC Building A structure that stands alone or that is cut off
from adjoining structures by fire walls with all
openings therein protected by
approved fire doors.
NEC Cabinet An enclosure that is designed for either surface
mounting or flush mounting and is provided
with a frame, mat, or trim in which a swinging
door or doors are or can be hung.
NEC Circuit Breaker A device designed to open and close a circuit
by nonautomatic means and to open the circuit
automatically on a predetermined overcurrent
without damage to itself when properly applied
within its rating. The automatic opening
means can be integral, direct acting with the
circuit breaker, or remote from the circuit
breaker.
NEC Classified Location Hazardous location, as defined in the NEC
Article 500, where fire or explosion hazards
may exist due to flammable gases, flammable
liquid–produced vapors, combustible
liquid–produced vapors, combustible dusts,
or ignitable fibers/flyings.
NFPA 70E Conductive Suitable for carrying electric current.
NEC Conductor, Bare A conductor encased within material of
composition or thickness that is not recognized
by the NEC as electrical insulation.
NEC Conductor, Insulated A conductor encased within material of
composition and thickness that is recognized by
the NEC as electrical insulation.
NEC Controller A device or group of devices that serves to
govern, in some predetermined manner, the
electric power delivered to the
apparatus to which it is connected.
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UL 817 Cord Connector A female contact device that is wired on
flexible cord and that contains one or more
receptacles.
UL 817 Cord Set (Extension A length of flexible cord assembled with an
Cord) attachment plug or current tap as a line fitting,
and a cord connector as a load fitting.
NFPA 70E Current-Limiting A device that, when interrupting currents in its
Overcurrent current- limiting range, reduces the current
Protective Device flowing in the faulted circuit to a magnitude
substantially less than that obtainable
in the same circuit if the device were replaced
with a solid conductor having comparable
impedance.
NFPA 70E Cutout An assembly of a fuse support with either a
fuseholder, fuse carrier, or disconnecting
blade. The fuseholder or fuse carrier may
include a conducting element (fuse link), or
may
act as the disconnecting blade by the inclusion
of a nonfusible member.

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NFPA 70E De-energized Free from any electrical connection to a source
of potential difference and from electrical
charge; not having a potential
different from that of the earth.
NEC Device A unit of an electrical system, other than a
conductor, that carries or controls electric
energy as its principal function.
NFPA 70E Diagnostics Taking readings or measurements of electrical
equipment with approved test equipment that
does not require making any physical change to
the equipment. Includes testing and
troubleshooting.
LBNL Direct Field A designated competent QEW is present on site
Supervision
and is providing oversight, guidance and
instruction on a specific
task or set of tasks to another person. See 6.11.
NEC Disconnecting Means A device, or group of devices, or other means
by which the conductors of a circuit can be
disconnected from their source of supply.
NFPA 70E Disconnecting (or A mechanical switching device used for
Isolating) Switch isolating a circuit or equipment from a source of
(Disconnector, power.
Isolator)
NEC Dwelling Unit A single unit, providing complete and
independent living
facilities for one or more persons, including
permanent provisions for living, sleeping,
cooking, and sanitation.
NEC Electrical Equipment A general term, including fittings, devices,
appliances, luminaires, apparatus,
machinery, and the like used as a part of, or
in connection with, an electrical installation.
Electrical equipment can be classified as
premises wiring or utilization equipment.
NFPA 70E Electrical Hazard A dangerous condition such that contact or
equipment failure can result in electric
shock, arc flash burn, thermal burn, or blast.
Class 2 power supplies, listed low voltage
lighting systems, and similar sources are
examples of circuits or systems that are not
considered an electrical
hazard.
NFPA 70E Electrical Safety Recognizing hazards associated with the use of
Page 286 of 217
 electrical
energy and taking precautions so that hazards do
not cause injury or death
NFPA 70E Electrically Safe A state in which an electrical conductor or
Work Condition circuit part has been disconnected from
energized parts, locked/tagged in accordance
with the LBNL Lockout/Tagout Program,
tested to ensure the absence of voltage (Zero
Voltage Verification
– ZVV), and grounded if determined necessary.
LBNL Electrical Work Any job or task requiring a Qualified Electrical
Worker. It includes any work that involves a
shock or arc flash hazard
or creates potential a shock or arc flash
hazards, energized or deenergized.
IEEE Electrostatic Electrical discharges of static electricity that
Discharge (ESD) build up on personnel or equipment, generated
by interaction of dissimilar materials. The
sudden transfer of charge between bodies of
differing electrostatic potentials that may
produce voltages or currents that could destroy
or damage electrical components.

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NEC Enclosed Surrounded by a case, housing, fence, or
wall(s) that prevents persons from accidentally
contacting energized
parts.
NFPA 70E Enclosure The case or housing of apparatus — or the
fence or walls surrounding an installation to
prevent personnel from accidentally contacting
energized electrical conductors or circuit parts
or to protect the equipment from physical
damage.
NEC Energized Electrically connected to, or is, a source of
voltage.
ASTM Energy of The incident energy (cal/cm2) on a material or a
F1959/F195 Breakopen material system that results in a 50% probability
9M Threshold (EBT of breakopen.
or EBT) Breakopen is a material response evidenced by
the formation of one or more holes in the
innermost layer of arc- rated material that
would allow flame to pass through the
material. Breakopen is defined as a hole with
an area of 1.6
cm2 (0.5 in2) or an opening of 2.5 cm
(1.0 in.) in any dimension.
NEC Equipment A general term, including, fittings, devices,
appliances, luminaires, apparatus,
machinery, and the like, used as a part of, or
in connection with, an electrical installation.
NFPA 70E Exposed (as applied Capable of being inadvertently touched or
approached nearer than a safe distance by a
to energized electrical person. It is applied to electrical conductors or
conductors or circuit circuit parts that are not suitably guarded,
parts) isolated, or insulated.
NEC Exposed (as On or attached to the surface or behind panels
applied to wiring designed to allow access.
methods)
NEC Fitting An accessory such as a locknut, bushing, or
other part of a wiring system that is intended
primarily to perform a mechanical rather than
an electrical function.
NFPA 70E Fuse An overcurrent protective device with a circuit-
opening fusible part that is heated and severed
by the passage of overcurrent through it. A fuse
comprises all the parts that form a unit capable
of performing the prescribed functions. It
may or may not be the complete device
necessary to connect it into an electrical
Page 288 of 217
 circuit.
NEC Ground The earth
NFPA 70E Ground Fault An unintentional, electrically conducting
connection between an ungrounded conductor of
an electrical circuit and the normally non–
current-carrying conductors, metallic
enclosures, metallic raceways, metallic
equipment, or earth.
NEC Grounded Connected (connecting) to ground or to a
(Grounding) conductive body that extends the ground
connection.
NEC Grounded, Solidly Connected to ground without inserting any
resistor or impedance device.
NEC Grounded Conductor A system or circuit conductor that is
intentionally grounded.

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NEC Ground-Fault A device intended for the protection of
Circuit personnel that functions to de-energize a circuit
Interrupter or portion thereof within an established period
(GFCI) of time when a current to ground exceeds the
values established for a Class A device. Class
A ground- fault circuit-interrupters trip when
the current to ground is 6 mA or higher and do
not trip when the current to ground is less than
4 mA. For further information, see ANSI/UL
943, Standard for Ground-Fault Circuit
Interrupters.
NEC Grounding The conductive path(s) that provides a
ground-fault current path and connects
Conductor, normally non–current-carrying metal parts of
Equipment equipment together and to the system
(EGC) grounded conductor or to the grounding
electrode conductor, or both.
NEC Grounding Electrode A conducting object through which a direct
connection to earth is established.
NEC Grounding A conductor used to connect the system
Electrode grounded conductor or the equipment to a
Conductor grounding electrode or to a
point on the grounding electrode system.
NEC Guarded Covered, shielded, fenced, enclosed, or
otherwise protected by means of suitable
covers, casings, barriers, rails, screens, mats, or
platforms to remove the likelihood of approach
or contact by persons or objects to a point of
danger.
NFPA 70E Hazard A source of possible injury or damage to health.
NFPA 70E Hazardous Involving exposure to at least one hazard.
NFPA 70E Incident Energy The amount of thermal energy impressed on a
surface, a certain distance from the source,
generated during an
electrical arc event. Incident energy is typically
expressed in calories per square centimeter
(cal/cm2).
NFPA 70E Incident Energy A component of an arc flash risk assessment
Analysis used to predict
the incident energy of an arc flash for a specified
set of conditions.
NFPA 70E Insulated Separated from other conducting surfaces by a
dielectric (including air space) offering a high
resistance to the passage of current. When an
Page 290 of 217
 object is said to be insulated, it is understood to
be insulated for the conditions to which it is
normally subject. Otherwise, it is, within the
purpose of these rules, uninsulated.
NFPA 70E Interrupter Switch A switch capable of making, carrying, and
interrupting specified currents.
NEC Interrupting Rating The highest current at rated voltage that a
device is identified to interrupt under
standard test conditions. Equipment intended
to interrupt current at other than fault
levels may have its interrupting rating
implied in other ratings, such as
horsepower or locked rotor current.
NEC Isolated (as applied to Not readily accessible to persons unless special
location) means for
access are used.
LBNL Job (electrical) An assigned set of tasks to complete a
certain scope of work.
LBNL Job Briefing A verbal communication of the job plan by the
person in charge to the persons involved with
the job. A job briefing is
required for EVERY JOB.

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NFPA 70E Labeled Equipment or materials to which has been
attached a label, symbol, or other identifying
mark of a Nationally Recognized Testing
Laboratory (NRTL), and by whose labeling the
manufacturer indicates compliance with
appropriate
standards or performance in a specified manner.
NFPA 70E Listed Equipment, materials, or services included in a
list published by a Nationally Recognized
Testing Laboratory (NRTL).
The means for identifying listed equipment
may vary for each NRTL; some NRTLs do not
recognize equipment as listed unless it is also
labeled. The authority having jurisdiction
should utilize the system employed by the
listing
organization to identify a listed product.
NEC Luminaire A complete lighting unit consisting of a light
source, such as a lamp or lamps, together with
the parts designed to position the light source
and connect it to the power supply. It may
also include parts to protect the light source or
the ballast or to distribute the light. A
lampholder itself is not a luminaire.
UL 61010-2 Measurement A classification system in UL 61010-2 for
Category (CAT rating the transient overvoltage capability of
rating) testing and measuring instruments according to
the type of mains circuits to which they are
intended to be connected. For example, typical
voltmeters are rated at CAT IV, 600 V.
Measurement categories take into account
overvoltage categories, short-circuit current
levels, the location in the building installation
at which the test or measurement is to be made,
and some forms of
energy limitation or transient protection
included in the building installation.
NEC Motor Control Center An assembly of one or more enclosed sections
(MCC)
having a common power bus and principally
Page 292 of 217
 containing motor control
units.
OSHA Nationally An organization, which is recognized by OSHA
and which tests for safety, and lists or labels or
Recognized Testing accepts, equipment or materials. See 29 CFR
Laboratory (NRTL) 1910.7.
NFPA 70E Non-QEW A person who is not a Qualified Electrical
Worker.
NEC Outlet A point on the wiring system at which current
is taken to supply utilization equipment.
NEC Overcurrent Any current in excess of the rated current of
equipment or the ampacity of a conductor. It
may result from overload, short circuit, or
ground fault. A current in excess of rating may
be accommodated by certain equipment and
conductors for a given set of conditions.
Therefore, the rules
for overcurrent protection are specific for
particular situations.
NEC Overload Operation of equipment in excess of normal,
full-load rating, or of a conductor in excess of
rated ampacity that, when it persists for a
sufficient length of time, would cause damage
or dangerous overheating. A fault, such as a
short circuit or ground fault, is not an overload.

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NEC Panelboard A single panel or group of panel units designed
for assembly in the form of a single panel,
including buses and automatic overcurrent
devices, and equipped with or without switches
for the control of light, heat, or power circuits;
designed to be placed in a cabinet or cutout box
placed in or against a wall, partition, or other
support; and accessible only from the
front.
NEC Premises Wiring Interior and exterior wiring, including power,
(System)
lighting, control, and signal circuit wiring
together with all their associated hardware,
fittings, and wiring devices, both permanently
and temporarily installed. This includes: (a)
wiring from the service point or power source
to the outlets; or (b) wiring from and including
the power source to the outlets where there is
no service point. Such wiring does not include
wiring internal to appliances, luminaires,
motors, controllers, motor control centers, and
similar equipment. Power sources include, but
are not limited to, interconnected or stand-
alone batteries, solar photovoltaic systems,
other distributed
generation systems, or generators.
NFPA 70E Qualified Electrical One who has demonstrated skills and
Worker (QEW) knowledge related to the construction and
operation of electrical equipment and
installations, has received safety training to
identify and
avoid the hazards involved, and who has been
approved or accepted by the Electrical AHJ for
Safe Work Practices.
LBNL QEW Supervisor A QEW who is also a work lead, activity lead
or supervisor, providing daily supervision to a
QEW or group of QEWs. The QEW supervisor
must be of the same level or higher than
those supervised in order to direct specific
electrical aspects of the work.
NEC Raceway An enclosed channel of metal or nonmetallic
materials
Page 294 of 217
 designed expressly for holding wires, cables,
or busbars, with additional functions as
permitted in this standard.
NEC Receptacle A receptacle is a contact device installed at the
outlet for the connection of an attachment plug.
A single receptacle is a single contact device
with no other contact device on the
same yoke. A multiple receptacle is two or more
contact devices on the same yoke.
NFPA 70E Repair Any physical alteration of electrical equipment
(such as making or tightening connections,
removing or replacing
components, etc.).
NFPA 70E Risk A combination of the likelihood of occurrence
of injury or
damage to health and the severity of injury or
damage to health that results from a hazard.
NFPA 70E Risk Assessment An overall process that identifies hazards,
estimates the potential severity of injury or
damage to health, estimates the likelihood of
occurrence of injury or damage to health, and
determines if protective measures are required.
As used
in this manual, arc flash risk assessment
and shock risk assessment are types of risk
assessments.

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LBNL Safety Watch A more stringent hazard control measure than
the Standby Person that must be implemented
when there are grave consequences from a
failure to follow safe work procedures. The
Safety Watch must be a QEW and must have
no other
duties other than monitoring the work of the
QEW.
NEC Service Drop The overhead conductors between the utility
electric supply system and the service point.
NEC Service Lateral The underground conductors between the
utility electric supply system and the
service point.
NEC Service Point The point of connection between the facilities of
the serving utility and the premises wiring. The
service point can be described as the point of
demarcation between where the serving utility
ends and the premises wiring begins. The
serving utility generally specifies the location of
the service
point based on the conditions of service.
NFPA 70E Shock Hazard A dangerous condition associated with the
possible release
of energy caused by contact or approach to
energized electrical conductors or circuit parts.
NEC Short-Circuit Current The prospective symmetrical fault current at a
Rating nominal voltage to which an apparatus or
system is able to be connected without
sustaining damage exceeding defined
acceptance criteria.
NFPA 70E Single-Line Diagram A diagram that shows, by means of single lines
and graphic symbols, the course of an electric
circuit or system of circuits
and the component devices or parts used in the
circuit or system.
NEC Special Permission The written consent of the authority having
jurisdiction.
LBNL Standby Person A second person designated to fulfill the
requirements of working accompanied when a
QEW is performing certain types of high hazard
electrical work. While the primary purpose of a
second person is to initiate the emergency
response system, a Standby Person is also
expected to
Page 296 of 217
 know how to deenergize electrical equipment
and to safely release a QEW from contact
with energized parts.
NFPA 70E Step Potential A ground potential gradient difference that can
cause current flow from foot to foot through the
body.
NEC Structure That which is built or constructed.
NEC Switch, Isolating A switch intended for isolating an electric
circuit from the source of power. It has no
interrupting rating, and it is intended to be
operated only after the circuit has been
opened by some other means.
NEC Switchboard A large single panel, frame, or assembly of
panels on which are mounted on the face, back,
or both, switches, overcurrent and other
protective devices, buses, and usually
instruments. These assemblies are generally
accessible from the rear as well as from the
front and are not intended
to be installed in cabinets.
NFPA 70E Switchgear, Arc- Equipment designed to withstand the effects of
Resistant an internal
arcing fault and that directs the internally
released energy away from the employee.

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NFPA 70E Switchgear, Metal- A switchgear assembly completely enclosed on
Clad
all sides and top with sheet metal, having
drawout switching and interrupting devices, and
all live parts enclosed within
grounded metal compartments.
NFPA 70E Switchgear, Metal- A switchgear assembly completely enclosed on
Enclosed
all sides and top with sheet metal (except for
ventilating openings and inspection windows),
containing primary power circuit switching,
interrupting devices, or both, with buses and
connections. This assembly may include
control and auxiliary devices. Access to the
interior of the enclosure is provided by doors,
removable covers, or both. Metal-
enclosed switchgear is available in non-arc-
resistant or arc- resistant constructions.
LBNL Switching The manual operation (opening or closing) of
any electrical isolation on energized
equipment. Manual operation includes the
operation of through-the-door breaker handles
or other dead-front switching.
NFPA 70E Switching Device A device designed to close, open, or both,
one or more electric circuits.
UL 489 Switching Duty (SWD) A molded case circuit breaker intended to
Circuit Breaker switch fluorescent lighting loads on a regular
basis. It is marked with a “SWD”.
LBNL Task (electrical) A specific step in a work procedure; a subset of
a job.
LBNL Temporary Use Wiring system, such as extension cords or other
flexible cord set, used for powering equipment
where the fixed premises wiring system is not
installed or accessible. Guidelines for time
duration are:
a. Construction: temporary wiring can be
installed for the duration of construction.
b. Experiment: temporary wiring can be
installed for the duration of the
experiment.
c. Holiday lights: temporary wiring can be

Page 298 of 217

 installed for a maximum of 90 days.
d. Other: temporary wiring can be installed
for the duration of use.
NFPA 70E Testing See Diagnostics
NFPA 70E Touch Potential A ground potential gradient difference that can
cause current flow from hand to hand, hand to
foot, or another path, other than foot to foot,
through the body.
NFPA 70E Troubleshooting See Diagnostics
NEC Unclassified Location Locations determined to be not Classified
per the NEC Article 500.
NEC Ungrounded Not connected to ground or to a conductive
body that extends the ground connection.
NEC Utilization Equipment Equipment that utilizes electric energy for
electronic, electromechanical, chemical,
heating, lighting, or similar purposes. Typically
refers to the load equipment as distinguished
from generating or distribution equipment,
which are part of the Premises Wiring.

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 Visual Inspection Examination of a circuit that has not been placed
in an Electrically Safe Work Condition, from
outside of the
restricted approach boundary, without working
on the circuit.
NEC Voltage (of a Circuit) The greatest root-mean-square (rms) (effective)
difference of potential between any two
conductors of the circuit concerned.
Some systems, such as three-phase 4-wire,
single-phase 3- wire, and 3-wire direct-current,
may have various circuits of various voltages.
NEC Voltage, Nominal A nominal value assigned to a circuit or
system for the purpose of conveniently
designating its voltage class (e.g., 120/240
volts, 480Y/277 volts). The actual voltage at
which a circuit operates can vary from the
nominal within a range that permits
satisfactory operation of equipment.
See ANSI C84.1, Electric Power Systems and
Equipment — Voltage Ratings (60 Hz).
NFPA 70E Working On Intentionally coming in contact with energized
(energized electrical conductors or circuit parts with the
electrical hands, feet, or other body parts, with tools,
conductors or probes, or with test equipment, regardless of the
circuit parts) personal protective equipment (PPE) a person
is wearing. There are two categories of
“working on”: diagnostic and repair (see
definitions).
LBNL Zero Voltage The practice of testing circuit parts for the
Verification (ZVV) absence of voltage. Includes the live-dead-live
check to verify tester
functionality.

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Appendix A: Standards on Personal Protective Equipment

Personal protective equipment (PPE) shall conform to the standards given in the following
table.

Subject Document Document

Number
Apparel — Arc Rated Standard Performance Specification ASTM F 1506
for Flame Resistant and Arc Rated
Textile Materials for Wearing
Apparel for Use by Electrical
Workers Exposed to Momentary
Electric Arc and Related Thermal
Hazards
Aprons — Insulating Standard Specification for Electrically ASTM F 2677
Insulating
Aprons
Eye and Face Protection — Practice for Occupational and Educational ANSI/ASSE
General Eye and Z87.1
Face Protection
Face — Arc Rated Standard Test Method for ASTM F 2178
Determining the Arc Rating and
Standard Specification for Face
Protective Products
Fall Protection Standard Specifications for Personal ASTM F 887
Climbing
Equipment
Footwear — Dielectric Standard Specification for Dielectric ASTM F 1117
Specification Footwear
Footwear — Dielectric Test Standard Test Method for Determining ASTM F 1116
Method Dielectric Strength of Dielectric Footwear
Footwear — Standard Standard Specification for Performance ASTM F 2413
Performance Specification Requirements for Foot Protection
Footwear — Standard Test Standard Test Methods for Foot ASTM F 2412
Method Protection
Gloves — Leather Standard Specification for Leather ASTM F 696
Protectors Protectors for
Rubber Insulating Gloves and Mittens
Gloves — Rubber Standard Specification for Rubber ASTM D 120
Insulating Insulating Gloves
Head Protection — Hard Personal Protection — Protective ANSI/ISEA
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Hats Headwear for Z89.1
Industrial Workers
Rainwear — Arc Rated Standard Specification for Arc and Flame ASTM F 1891
Resistant
Rainwear
Rubber Protective Standard Guide for Visual Inspection of ASTM F 1236
Products — Electrical
Visual Inspection Protective Rubber Products
Sleeves — Insulating Standard Specification for Rubber ASTM D 1051
Insulating Sleeves

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19 Appendix B: Standards on Other Protective Equipment

Other protective equipment shall conform to the standards given in the following table.

Subject Document Document

Number
Blankets, Arc Protective Standard Test Method for Determining ASTM F 2676
the Protective Performance of an Arc
Protective
Blanket for Electric Arc Hazards
Blankets, Rubber Standard Specification for Rubber ASTM D 1048
Insulating Insulating
Blankets
Covers, Rubber Insulating Standard Specification for Rubber ASTM D 1049
Insulating Covers
Fiberglass Rods — Live- Standard Specification for Fiberglass- ASTM F 711
Line Tools Reinforced
Plastic (FRP) Rod and Tube Used in Live
Line Tools
Insulated Hand Tools Standard Specification for Insulated and ASTM F 1505
Insulating
Hand Tools
Ladders American National Standard for Ladders ANSI A14.5
— Portable
Reinforced Plastic — Safety
Requirements
Line Hose Standard Specification for Rubber ASTM D 1050
Insulating Line
Hose
Plastic Guard Standard Test Methods and Specifications ASTM F 712
for Electrically Insulating Plastic Guard
Equipment for
Protection of Workers
PVC Sheeting Standard Specification for PVC Insulating ASTM F 1742
Sheeting
Safety Signs and Tags Series of Standards for Safety Signs and ANSI Z535
Tags Series
Shield Performance on Standard Test Method for Determining ASTM F 2522
Live-Line Tools the Protective Performance of a Shield
Attached on Live Line Tools or on
Racking Rods for Electric Arc
Hazards
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Temporary Protective Standard Specifications for Temporary ASTM F 855
Grounds — Test Protective Grounds to Be Used on De-
Specification energized Electric Power
Lines and Equipment

Page 304 of 217

Appendix C: In-Service Specifications for Personal and Other Protective Equipment

Personal and other protective equipment shall conform to the in-service care
requirements given in the following table.

Subject Document Document

Number
Blankets — Rubber Standard Specification for In-Service ASTM F 479
Insulating Care of
Insulating Blankets
Gloves and Sleeves – Standard Specification for In-Service ASTM F 496
Rubber Care of
Insulating Insulating Gloves and Sleeves
Rubber Protective Standard Guide for Visual Inspection of ASTM F 1236
Products — Electrical
Visual Inspection Protective Rubber Products
Line Hose and Covers Standard Specification for In-Service ASTM F 478
Care of
Insulating Line Hose and Covers
Temporary Protective Standard Specification for In-Service ASTM F 2249
Grounds Test Methods for Temporary Grounding
Jumper Assemblies Used on De-
Energized Electric Power Lines and
Equipment

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Appendix D: Reference Sheet for the QEW Skill of the Craft Work
PLAN EVERY JOB

Ste Instruction Manual

p Reference(s)
PLAN THE WORK
1. Designate a Person In Charge (PIC) • 6.1
a. Must be competent for the task
b. Part of the planning process
c. Responsible for the safe execution of the work

2. Determine the scope of work • 4.4

a. Determine what needs to be performed
• 4.1.7
b. Determine type of electrical work • 6.3-6.7
c. Always perform work in an Electrically Safe Work

Condition where possible

3. Analyze the hazards • 4.3.5
a. Perform a shock hazard analysis
• 7.1
b. Perform an arc flash hazard analysis • 8.1
c. Determine approach boundaries • 10.2
d. Consider body positioning constraints
4. Determine qualification requirements • 6.2
a. QEW level
• 6.10
b. Experience level with specific equipment and/or task
5. Select the appropriate personal protective equipment (PPE) and • 7.6
• 7.9
barriers
a. Voltage gloves • 8.10
b. Voltage blankets
c. Arc flash PPE
d. Arc-rated blankets
6. Determine tools required • 7.3.2.f
a. Listed, used for correct purpose, unmodified and in good
• 18.1
condition • 18.3
b. Appropriate training received for using the tools
7. Determine if 2-Person Rule applies • 6.13.3
a. Standby Person
• 6.13.4
b. Safety Watch
8. Set up area access controls • 10.3.3
a. Barricades
• 10.3.4
b. Attendants

9. Determine additional controls as necessary • 4.3.6

• 4.4
10. Obtain line management authorization to perform • 4.5
troubleshooting
Page 306 of 217
a. Who is performing the work? Are they suitably qualified
and experienced?
b. Who is supervising the work? Are they suitably qualified
and experienced?
c. Is a written procedure necessary or advised (ESWP)?
d. Are any permits required and have they been approved?
e. What plant operational conditions will (or should) be
required? Are these accounted for in

Page 307 of 217

 the plan?
f. What could go wrong and what should be done
about it? Is the level of planning and supervision
appropriate for the level of risk?
BRIEF AND PERFORM THE WORK
11. PIC performs a Job Briefing • 6.9
a. Brief every person who participates or who is in the area
• 4.7
b. Provide overview of hazards and controls
c. Run through QEW self-control questions

12. Control access to the work area • 10.3

13. PIC controls access to the work site • 6.9
a. Access restricted to essential personnel only
• 10.3
b. Brief every person who comes in the area • 7.3.2.c
c. A QEW must escort a non-QEW within the Limited

Approach Boundary
d. If PIC cannot control access, designate an Attendant to

perform the function

14. Perform the work • 4.1.5
a. Perform work within the controls
• 9.4.4
b. Always Test Before Touch
c. Be alert for changes to job scope. STOP AND
REASSESS.
d. Maintain good housekeeping and cleanliness
e. Anticipate problems
f. Resist pressure to "hurry up"
g. Maintain a questioning attitude
FEEDBACK
15. Debrief and record lessons learned for future improvement. • 4.2.4.e

Page 308 of 217

Appendix E: List of Pre-Approved Voltage Detectors for Zero Voltage Verification

Pictu Model Specifications

re
Fluke T5 T5-600: 600V ac/dc,
CAT III T5-1000:
1000V ac/dc, CAT III
600V ac/dc, CAT
IV

Fluke 381 1000V ac/dc, CAT III

600V ac/dc, CAT IV

Remote Display True-

RMS AC/DC Clamp
Meter with iFlex

Fluke 70 III 600V ac/dc, CAT II

NOTE: This model

has been discontinued
and is replaced by the
Fluke 115

Page 309 of 217

Pictu Model Specifications
re
Fluke 115 600V ac/dc, CAT

III True-RMS

multi-meter

Fluke 113 600V ac/dc, CAT III

300V ac/dc, CAT IV

True-RMS AC/DC
Utility multi- meter

Fluke 117 600V ac/dc, CAT III

Digital Multimeter
with Non- Contact
Voltage

Page 310 of 217

Pictu Model Specifications
re
Fluke 175 1000V ac/dc, CAT III
600V ac/dc, CAT IV

True-RMS digital
multimeter

Fluke 177 1000V ac/dc, CAT III

600V ac/dc, CAT IV

True-RMS digital
multimeter

Fluke 179 1000V ac/dc, CAT III

600V ac/dc, CAT IV

True-RMS digital
multimeter

Page 311 of 217

Pictu Model Specifications
re
Fluke 189 1000V ac/dc, CAT III
600V ac/dc, CAT IV

True-RMS data-
logging digital
multimeter

Fluke 233 1000V ac/dc, CAT III

600V ac/dc, CAT IV

Remote Display
True-RMS AC/DC
multi-meter

Fluke 289 1000V ac/dc, CAT III

600V ac/dc, CAT IV

True-RMS data-logging
digital multimeter

Page 312 of 217

Pictu Model Specifications
re
Fluke PRV240 240 VAC output,
battery- powered
proving unit for
contact voltmeters

Fluke 80K- 6kV, 15 kV or 40 kV

6/15/40 depending on model
AC or
DC Cat I
only
For research equipment
fed from high
voltage/low current
power supplies only

NOT FOR USE ON

PREMISES WIRING
SYSTEMS

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