Unit-2 Electrical safety

Workplace hazardous systems are designed to protect

the health and safety of workers. Information must be
provided about the safe handling, usage, storage and
disposal of hazardous systems. Workplace hazard is
something that can have potential to harm the technician.
There are hazards in every type of job and every type
of workplace. Everyone at the workplace shares the
responsibility to identify and control the hazards. The
technician must first recognise the hazards at the
workplace. When the technician installs or assembles
the components, she/he may have to face hazards which
are related to the workplace. For instance, these hazards
can be associated with the installation and assembly
process of a water purifier. The technician should be
aware of the hazards associated with the installation of
a water purifier. Majority of the hazards can be avoided
by being aware and taking appropriate precautions.

Electrical Hazard
An electrical hazard defines a dangerous condition. This
dangerous condition is related to energised equipment
or a conductor at workplace. If a technician comes
in contact with the energised equipment, then the
equipment may cause injury to the technician. There is
a possibility of being electrocuted or getting an arc flash
burn, thermal burn or blast injury while assembling
the components in a unit. Many of the hazards can
be avoided by being aware and taking appropriate Fig. 3.22 Safe work in an
precautions. This will ensure safety at workplace electrical system
(Fig. 3.22).
Points that need to be remembered for working safely
around electrical panel and cabinet are as follows.
1. Watch out for loose cords and wires. Loose cords
and wires can cause physical hazards and even
electrical hazards. Hazard Tape should be placed
if a cord or wire is placed on a pathway.

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 2. Wear proper personal protective equipment.
The kind of personal protective equipment (PPE)
required around a machine will depend upon
the type of machine and task the employee is
performing. Nevertheless gloves, hardhats, safety
glasses, earplugs and other gears are important
to use where necessary. For safety, signs can
be posted near panels reminding employees to
wear PPE (Figs. 3.23 and 3.24).
Fig. 3.23 Loose cord which can be
hazardous 3. Use caution around heat sources. Some panel
and equipment get hot while operating. Everyone
should be aware of these areas and use caution
when nearby. PPE like gloves or flame-resistant
clothing may be required in these areas.
Fig. 3.24 Hazard tape 4. Be careful when cleaning: When cleaning around
a panel or equipment, one should note other
possible hazards too (Fig. 3.24):
⚫ Fire and explosion hazards
⚫ Need for PPE during cleaning
⚫ Risk of electric shock
Follow visual and written instructions panel,
equipment has signs and labels on them alerting
employees to hazards (Fig. 3.25).
5. Be cautious while testing, replacing
safety helmet
eye protection the components in the panel. All
levels of voltage should be considered
dust mask
ear plugs equally dangerous. Even the voltage
levels which cannot produce
protective electrical shock should also not
gloves
high visibility
be ignored. We should check and
clothing confirm that the circuit is dead
laced safety
footwear before touching it for repairing
Fig. 3.25 Personal protection equipment maintenance or any other work.
6. Avoid water at all times when working with
electricity. Never touch or try repairing any
electrical equipment or circuits with wet hands.
It increases the conductivity of electric current
(Fig. 3.26).
7. Never use equipment with damaged insulation or
broken plugs.
8. If you are repairing an electrical device always
turn off the mains supply.
 9. Always use insulated tools while working.
10. Always use appropriate insulated rubber gloves
and goggles while working on any branch circuit
or any other electrical circuit.
11. Never try repairing energised equipment. Always
check that is de-energised first by using a tester.
Chemical hazards are caused due to
1. improper storage of chemicals causing a chemical Fig.3.26 Avoid water while
working with electricity
leakage
2. mishandling of chemicals due to inadequate
training or negligence.

Fire Extinguisher
A fire extinguisher (Fig. 3.27) is a protection device
used to cease fire. It is the basic first aid equipment
which can be effectively used for controlling fire. A fire
extinguisher is a cylindrical pressure vessel containing
an agent which can be discharged to cease a fire. A fire
extinguisher should always be available in areas where
persons work with electrical equipment.
Different parts of a fire extinguisher are shown in
Fig. 3.27.
Pin and Seal
The following steps demonstrate the operation
of a fire extinguisher in case of a fire emergency. Gauge

Step 1: Identify the safety pin of the fire Hose

extinguisher which is generally present in its
handle
Step 2: Break the seal and pull the safety pin
from the handle Nozzle

Step 3: Use the fire extinguisher by squeezing

Inspection
the lever
Tag
Step 4: Sweep it from side to side
Fig. 3.27 Parts of fire extinguisher

First Aid for Electrical Emergencies

Electrical accidents cause countless injuries. Injury
could be minimised and many lives saved if proper
rescue techniques and treatments are used. Electrical
accidents may occur at any time or place. Timely
response and treatment of victims is a major concern.
When an electrical accident occurs, due to the effect of
NOTES muscle clamping, a victim is often incapable of moving
or releasing the electrical conductor. Caution should be
a primary consideration during any electrical accident
or emergency. There should always be an emergency
response plan for scheduled electrical maintenance
or work.

Electrical Rescue Techniques

(a) Approaching the accident
⚫ Never rush into an accident situation
⚫ Call 108 as soon as possible
⚫ Approach the accident place cautiously
Swollen tongue may Irregular heartbeat
or Cardiac arrest Exit Burn
obstruct airway
Paralysis

Vision Difficulty in
Problems breathing or
respiratory arrest

Fractured
bones

Entry Burn

Muscle tenderness
and possible twitching
Fig. 3.28 Wireman in an unconscious state because of an electrical shock

(b) Examining the scene

⚫ Visually examine victims to determine if they are
in contact with energised conductors (Fig. 3.28).
⚫ Metal surfaces, objects near the victim may also
be energised (Figs. 3.29 and 3.30).

Fig. 3.29 Victim in contact with energised conductor

 ⚫ You may become a victim if you touch an energised
victim or conductive surface. Do not touch the
victim or conductive surfaces while they are
energised.
⚫ Switch off the electrical circuits if possible.
(c) Hazards and solutions
⚫ Be alert for hazards, such as heated surfaces and
fire etc.
⚫ In case you cannot switch off the power source,
take extreme care
⚫ Ensure that your hands and feet are dry
⚫ Wear protective equipment, such as gloves and
shoes. Stand on a clean dry surface
⚫ Use non-conductive material to remove a victim
from the conductor (Fig. 3.30)
(d) High voltage rescue
⚫ Special training is required for rescues
if high voltage is present
⚫ Protective equipment, such as gloves
and shoes must be worn
(e) First aid
Fig. 3.30 Use of non-conductive material to
⚫ A victim may require Cardio-Pulmonary rescue the victim
Resuscitation (CPR). Steps to perform
in CPR are shown in the Figs. 3.31, 3.32 and 3.33.
⚫ If the victim is breathing and has a heartbeat,
give first aid for injuries and treat for shock.
⚫ Ensure the victim gets medical care as soon
as possible.
⚫ Physician attending the victim must have
detailed information to properly diagnose and
care for the victim. The physician must determine
whether the victim should be sent to a Trauma or
Burn Centre.

Fig. 3.31 Chest compression Fig. 3.32 Open the mouth for airway Fig. 3.33 Rescue breathing
Some statutory requirements for electrical safety in India include:

 Identification: Grounded and earthed neutral conductors must be properly identified.

 Bare conductors: Bare conductors must be inaccessible.

 Electrical fires: Adequate arrangements must be available to fight electrical fires.

 Testing: Consumer installations must be tested before reconnection or additional supply.

 Earth leakage: An earth leakage protective device must be installed.

 High voltage: Equipment and apparatus intended for use at high or extra high voltage must
be inaccessible to unauthorized people.

 Inspection and testing: Electric supply lines that are protected by bituminous materials
must be periodically inspected and tested. The results of each inspection and test must be
recorded.

 Maintenance: Regular maintenance and inspection can help prevent harm, improve
efficiency, and extend the life of electrical equipment.

Bureau of Indian Standards

To promote the safety and the right usage of equipment, there are certain rules and regulations
formulated by the Bureau of Indian Standards (BIS). BIS follows the following five principles −
 Safety
 Ease of use and adaptability
 Simple technology
 Value for money products
 Energy efficiency and environment
BIS has published the following code of practice for public safety standards in order to promote
the right to information, transparency and accountability in a proper manner to the public.
Code of Practice for Electrical Wiring Installation
 IS − 732 (1989)

 Section − Electrical Installation

 Application − Design of installation, selection and erection of equipment, inspection and
testing of wiring system
Code of practice for Earthing
 IS − 3043 (1987)
 Section − Electrical Installation
 Application − Design, installation and calculation of Earthing system

Lightning arrester for Alternating Current System

 IS − 3070 (1993)

 Section − Electro technical: Surge Arresters

 Application − Identification, ratings, classification and testing procedure of Arrester.

Effects of Electrical parameters on Human Body

A closed circuit is essential for the safety of anyone that comes in contact with electricity.
Contact with electric voltage can cause the current to flow through the body, which can then
result in electric shock, burns and even death. This can happen in different scenarios or
situations. If two cables have different voltage, the current can flow through them if they are
connected. If you touch both cables at the same time, then your body becomes a conductor and
the current of electricity will pass through your body. Also, if you touch a cable that has current
flow and also touch an electric connection that is grounded, then you become the easiest path for
electricity to go to the ground. The severity of the injuries caused by an electric shock varies
depending on the voltage and the time that the current takes to pass through your body. The
amount of current a person can tolerate and still be able to control his or her hand and arm
muscles is less than 10 mA. However, it is important to mention that currents as low as 10
milliamps can cause muscle contractions. The damage that the current of electricity can do
depends on different factors: the intensity of the voltage, the length of the exposure, the muscle
structure of the individual, and other different conditions. People with less muscular tissue are
usually affected at lower levels of electric current. Electric shocks, depending on certain
conditions, can be fatal, even at relatively low voltages. The amount of time that an electrical
current lasts has a great influence in the severity of the injuries. If the electric current has a short
duration, then it may just cause pain. If the electric shock is longer, then it can be fatal, even if
the voltage is not very high.
Take a look at the following chart: