Portable Appliance Testing:

A Practical Guide
SEAWARD

Seaward: CONTENTS

making your 04
05
Legislation
Who has responsibility?
life easier and 05 Competence, Training

more efficient and Experience

06 Types of Equipment
World-Leading Electrical Test
Equipment from Seaward 09 Classes of Equipment
Construction
At Seaward we have over three decades of
09 The Inspection Process
experience in the design and manufacture of
innovative electrical safety test equipment.
11 Combined Inspection
Today, our first-class range of products
serves a wide variety of testing and precision and Testing Procedure
measurement applications.
15 Electrical Tests
For the last 35 years we’ve moved our
developments on. Our portable appliance 21 Frequency of inspection
testers are the benchmark for the portable and testing based on
appliance testing (PAT) market and are risk assessment
regarded as number one by the industry.
Our PAT testing equipment has always been 23 Record Keeping
designed with the needs of our customers in
mind. Safety in the workplace is of paramount 27 Appendix
importance and our testers provide the quick
and effective key to electrical equipment
28 PAT Testers from
preventative maintenance programmes. That’s
why each Seaward PAT tester is backed by
Seaward
a huge range of accessories, printers, asset
management software and technical support. 32 PATGuard 3 Software
Peace of mind is guaranteed for our customers
because they know that help and advice is 33 Accessories and Services
always available. from Seaward

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 PAT: A PRACTICAL GUIDE

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PG 3
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Legislation systems shall be maintained so as to prevent,

so far as is reasonably practicable, such danger.”
(Regulation 4(2))

Although reference is made to legislation,

Provision and Use of Work Equipment
this guide should not be considered to be
Regulations 1998 places general duties on
legal advice. The reader should refer to the
employers and lists minimum requirements for
specific legislation and seek legal advice
work equipment to deal with selected hazards
where necessary, which may vary from time
whatever the industry.
to time.

The Regulations implement an EU Directive

aimed at the protection of workers and the
Health and Safety at Work Act 1974 (HSW
“general duties” will require the need to:
1974) places a duty of care on both the
employer and employee to ensure the safety of
aa Make sure that equipment is suitable for
all persons using the work premises.
the use for which it is provided.
bb Take into account the working conditions
Management of Health and Safety at Work
and hazards in the workplace.
Regulations 1999 state that every employer
cc Ensure equipment is used only for the
shall make suitable assessment of the risks to
operations for which, and under conditions
health and safety of his employees to which
for which, it is suitable.
they are exposed whilst at work and the risk
dd Ensure equipment is maintained in an
to health and safety of persons not in his
efficient state, in efficient working order
employement arising of or in connection with
and in good repair.
the conduct by him of his undertaking.
ee Provide equipment that conforms to EU
The management of Health and Safety at Work product safety directives
Regulations 1999 also states that: ff Plus certain other general duties and
specific requirements etc.
aa Every employer shall make a suitable
and sufficient assessment of the risks to Housing Act 2004 (England and Wales)
the health and safety of his employees to introduced a new method for assessing risk
which they are exposed whilst they are at in residential properties, called the Housing
work. Health and Safety Rating System, to provide a
bb Where the employer employs five or more safe and healthy environment for any potential
employees, he shall record the significant occupiers or visitors. This includes portable
findings of the assessment. electrical equipment and the condition of
associated leads and plugs should be taken
Electricity at Work Regulations 1989 apply to into account if they are provided as part of a
every type of electrical equipment and state: rented dwelling. Portable appliance testing
“As may be necessary to prevent danger, all is one method of ensuring that electrical
equipment is safe for continued use.

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 PAT: A PRACTICAL GUIDE

Housing (Scotland) Act 2006 defines the item is safe for continued use. Training and
statutory requirements that have to be met by experience will both be necessary.
a private landlord and includes the electrical
installation and electrical appliances. The Competence, Training
landlord must ensure that the property meets
the requirements at the start of the tenancy
and Experience
where the landlord is made aware of possible
The User
defects.
Users may require training in identification of
defects that can occur in electrical equipment.
Who has responsibility? Users should be aware that:

Users of Electrical Equipment aa Equipment that is faulty or suspected of

Users of electrical equipment have a being faulty should not be used.
responsibility to ensure that equipment bb Equipment that is faulty should be labelled
they use has no obvious visual damage or and removed from service immediately.
defects. The employer has a responsibility to cc The administrator or manager should be
provide and maintain a safe plant for every notified.
employee to use (HSW Act 1974 Sect 2 (a)). This
requirement is endorsed by the (EAWR 1989) The Duty Holder
Regs 4(1) and 4(2) with specific reference to The duty holder, normally a manager or
electrical equipment. The (EAWR 1989) Reg supervisor, is required to know their legal
3(1) also places the same duties upon the self- responsibilities as laid down in the Electricity
employed. at Work Regulations 1989 and have a legal
responsibility to ensure that equipment in their
Administrators charge is safe.
The IET Code of Practice gives advice to
persons managing maintenance schemes. Duty holders may require training to allow
Administrators or managers of premises them to carry out risk assessments, maintain
are required to understand and apply the records of inspections, tests and repairs of
legislation and assess the risks in respect of equipment and manage the inspections and
electrical equipment and appliances within tests at appropriate intervals. Duty holders are
their charge. Administrators have a legal required to interpret the recorded results and
responsibility to ensure that the electrical take appropriate actions or to provide relevant
equipment in their charge is safe. information and reports to a more senior
person within the organisation. Competence
Test Operative to interpret records and results is achieved by
The person performing the inspections and appropriate training and experience.
tests on an item of the equipment should be
competent to carry out the inspections and The Test Operative
tests, assess the results and conditions in which In the context of safety testing, the term
the item is being used and state whether the “competence” refers to a person’s ability to

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perform the task without danger to themselves aa Adequate experience of relevant electrical
or others and to make a valid judgement based work.
on the results, as to whether the unit under test bb Adequate experience of appliance testing
is safe and is likely to remain safe at least until and test equipment.
the next scheduled test date. cc Adequate training where (b) cannot be
otherwise satisfied.
It will be appreciated that the test person will dd Experience in the interpretation of results.
require certain knowledge and information ee Practical “technical” experience of the type
to enable such valid prospective judgements of equipment being tested.
to be made. In addition the test person will
require both the knowledge and information Suitable sources of information may include:
necessary to make judgements regarding the
testing process and its safety and the skill and aa Employer’s safety manuals or instructions.
ability to put such judgements into practice, bb Equipment manufacturer’s handbooks.
this producing a safe system of work. Training cc British Standards (see Appendix).
and experience will both be necessary. dd Health and Safety Executive (HSE)
Guidance Notes (see Appendix).
It is suggested that the following criteria are ee IET Code of Practice for In-Service
considered: Inspection and Testing of Electrical
Equipment.
aa An adequate knowledge and practical
experience of electricity and its hazards. Managers and supervisors responsible for
bb A clear understanding of precautions testing personnel should adjust their degree of
required to avoid danger. supervision to take into account an inadequacy
cc The ability to recognise at all times whether of the test person. The (EAWR 1989) Reg. 3
it is safe for work to continue. places a duty on the self employed to assess
dd The ability to identify equipment and their own competence and subsequently to
appliance types to determine the test work within their limitations.
procedures and frequency of inspection
and testing. Types of Equipment
ee Adequate understanding of the operating
principles of both the test equipment and The IET Code of Practice applies to equipment
the unit under test. supplied at voltages up to and including
ff The ability to create test records and take 1000V AC or 1500V DC between conductors
responsibility for the work. or 600V AC or 900V DC between conductors
gg Adequate knowledge of the required safety and earth including single, two and three-
standards. phase equipment supplied at 400V, 230V and
hh Adequate knowledge of possible hazards 110V and at extra-low voltage including SELV
at a “strange” site. (Separated Extra-Low Voltage). Several types
of electrical equipment are defined in the IET
The tester’s skill and ability should encompass: Code of Practice.

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 PAT: A PRACTICAL GUIDE

Portable Equipment Moveable Equipment (Transportable)

An appliance of less than 18kg in mass that is This equipment is either:

intended to be moved whilst in operation or an
appliance which can easily be moved from one ∙∙ 18kg or less in mass and not fixed, e.g.
place to another e.g. vacuum cleaner, toaster, electric fire or:
food mixer, etc. ∙∙ Equipment with wheels, castors or
other means to facilitate movement by
Hand Held Equipment or Appliances the operator as required to perform its
intended use e.g. air conditioning unit.

Such equipment may be considered

“transportable” rather than portable, but
will still be connected to its supply where
applicable by a flexible cable and plug.
The risk of damage which may cause the
safety of transportable equipment to be
compromised can be high. Also, the use of
some transportable equipment carries high
This is portable equipment intended to be held risk due to the very nature of its use (e.g. a
in the hand during normal use e.g. drill, hair high pressure steam/water cleaner) and in
dryer etc. such circumstances transportable equipment
can present a greater hazard than most
The risk of damage which may cause safety of portable equipment, therefore the requirement
the hand held equipment to be compromised to periodically test must also apply to
can be high. Also, the use of some hand held transportable equipment.
equipment carries a high risk due to the very
nature of its use i.e. the user is in direct contact
with the equipment.

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Stationary Equipment or Appliances Appliances or Equipment for Building In

This equipment has a mass exceeding 18kg This equipment is intended to be installed in a
and is not provided with carrying handle e.g. prepared recess such as a cupboard e.g. a built-
refrigerator, washing machine. in cooker.

Fixed Equipment/Appliances Information Technology Equipment

This is equipment or an appliance which is This equipment includes electrical business

fastened to a support or otherwise secured in equipment such as computers, mains powered
a specific location e.g. bathroom heater, towel telecommunications equipment and other
rail. Fixed equipment can also be movable or equipment for general business use e.g.
portable equipment, when connected to the printers, photocopiers, typewriters etc.
fixed installation via a fused connection unit
(FCU), for security purposes. This practice is Extension Leads and RCD Extension Leads
common in areas used by the general public, Extension leads are used where an item of
e.g. hotels, changing rooms etc. Equipment equipment requires connection to a mains
types connected in this way are numerous e.g. supply but a convenient outlet is not available.
kettles, lamps, hair dryers etc. An RCD extension lead is an extension lead
that is fitted with a residual current device.

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 PAT: A PRACTICAL GUIDE

Multi-way Adaptors and RCD Adaptors insulated” and should carry the symbol .
Multi-way adaptors are used where sufficient
mains outlets are not available. RCD adaptors Class III equipment is equipment in which
are used to provide protection for users of protection against electric shock relies on
portable equipment, particularly when used supply from a separated extra-low voltage
outdoors. source (SELV). In a SELV supply the voltage is
less than 50V rms and no exposed conductive
Classes of Equipment parts are connected to the protective

Construction conductor.

Before an item of equipment can be tested

Note: Not all double insulated equipment
the construction class must be determined
bears the mark, however, if the mark is
in order to identify the appropriate tests.
applied the equipment must be double
The equipment to be tested will normally
insulated. For the purposes of electrical safety
be constructed in one of three basic classes,
testing, if a piece of equipment does not bear
designated Class I, II or III. Constructional
the it should be treated as Class I.
methods are summarised below, full details
can be found in BS2754.

Class I equipment is constructed such that The Inspection Process

protection against electric shock does not rely
on basic insulation alone. In addition to basic User Check
insulation around live internal parts, exposed User checks are performed before equipment is
conductive parts around live internal parts, plugged in and switched on. The check involves
exposed conductive parts are connected to a visual inspection of the mains plug, mains flex
the protective conductor in the fixed wiring of and the appliance for obvious signs of damage
the electrical installation. Class I equipment or degradation. An assessment should also be
relies upon a connection to the protective made of the suitability of the environment and
conductor to prevent exposed conductive parts the purpose for which the equipment is to
becoming live in the event of a failure in the be used. User checks are an important safety
basic insulation. precaution as the user of the equipment is
most familiar with its operation. User checks
Class II equipment is constructed such that do not need to be recorded unless a problem
protection against electric shock does not is discovered, in which case the equipment
rely on basic insulation alone. In addition to should be labelled to show it is not to be used
basic insulation around live internal parts, and removed from service as soon as possible.
supplementary insulation is provided, there The administrator or manager should be
being no provision for connection of exposed notified.
conductive parts to the protective conductor.
Such equipment is often described as “double

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Formal Visual Inspection 3. Switching of equipment

In practice, many equipment defects can a. The inspector should determine
be found during a formal visual inspection. whether there are suitable means of
Many potential hazards arise due to the way disconnecting the equipment from
in which a piece of equipment is used or the mains supply under normal use, to
abused. For example, portable equipment carry out maintenance and in the event
may be prone to being dropped or a piece of an emergency (if applicable to the
of movable equipment with a long, trailing equipment).
mains flex may be damaged as the equipment
is moved around. Potential hazards such as 4. User feedback
enclosure damage, damage to the mains flex, a. Where possible the user of the equipment
signs of overheating, incorrectly fitted mains should be consulted as to whether there
plugs, incorrect fuses etc. can be identified by a are any known problems or faults. The user
thorough visual examination. may be aware of intermittent problems
that may not be apparent during the
A formal visual inspection carried out by a inspection.
competent person will make the greatest
contribution to minimising risk and eliminating 5. The equipment enclosure/casing
potential safety hazards. Advice on the a. Physical damage such as cracks or
frequency of formal visual inspections is given chemical corrosion. Particular attention
in Table F (see page 22). should be paid to areas around switches,
fuses, protective covers and mains
A formal visual inspection should include an couplers where damage may result in live
inspection of the following: parts becoming exposed.
b. Signs of overheating.
1. Manufacturer’s instructions c. Signs of ingress of fluids or foreign bodies.
a. The equipment should be installed
and used in accordance with the 6. Mains plugs
manufacturer’s instructions. a. Correct fit in the mains outlet - not loose
b. The correct voltage, frequency and current and can be removed without difficulty.
requirements should be verified. b. Cracks or damage.
c. Requirements for ventilation or heat c. Signs of overheating.
dissipation should be met. d. Properly tightened off terminal screws.
e. Correct wiring.
2. Environment f. Mains flex is properly secured by the cable
a. Suitability of the equipment for the grip.
environment or purpose for which it is g. Correct fuse rating and type.
being used e.g. risk of mechanical damage,
exposure to weather, temperature, fluids,
corrosives, flammable materials.

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 PAT: A PRACTICAL GUIDE

7. Mains Cables
a. Damage, cuts or fraying. Extension leads Note: The requirements of a formal
should be checked along with the entire visual inspection will vary according to
length. the equipment being inspected and
b. Joints or connections which are unsafe e.g. the environment in which it is used. The
taped joints. ‘prompts’ built into Seaward Portable
c. Appropriate length. Appliance Testers are intended to provide
d. Correct rating for the equipment. guidance and should not be taken as a
comprehensive list of items to be checked
8. RCD protected adaptors or extension during a formal visual inspection.
leads
a. Correct operation of the RCD should be
confirmed. Combined Inspection and
Testing Procedure
Operator accessible fuses on the outside of the
equipment should be checked for correct type Safety Considerations
and rating. If the equipment manufacturer Inspection and testing should only be carried
has specified a particular rating for the plug out by a person who is competent to perform
fuse, this should also be checked. If the the inspection and testing and interpret the
manufacturer has not specified a fuse rating results obtained.
for the plug the maximum current carrying
capacity is detailed in Table G (see page 26) Preliminary Inspection
related to the cross-sectional area of the cable Before inspection and testing is carried out
conductors. Ensure that properly manufactured the test operative should obtain a copy of any
cartridge fuses are used and that fuses have not previous test records if they are available. This
been replaced with a metal bar, wrapped in will allow an assessment to be made of any
metallic foil or similar non-standard method. degradation of the equipment under test.

Before attempting to carry out any electrical

safety tests, the following preliminary
inspection should be carried out:

a. Ensure that the equipment can be

disconnected from the mains supply
and other power sources. If permission is
received, disconnect the equipment from
the supply.
b. Disconnect the equipment from all other
equipment, communication links and
telecom lines.

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c. Where the equipment under test has The order in which the tests are performed is
the provision to supply mains power to important to the safety of the test operative.
other accessories (for example a monitor The testing sequence of Seaward’s portable
powered from PC base station) the mains appliance testers is designed to contribute
connection can remain in place during the towards a safe system of work. The sequence
tests. should always be:
d. Ensure that equipment is not in contact
with extraneous metalwork such as parts 1. Earth continuity test.
of office furniture. 2. Insulation resistance test.
e. Thoroughly inspect the equipment under 3. Protective conductor/touch current test or
test for damage, as described in Formal alternative/substitute leakage test.
Visual Inspection. 4. Functional Check.
f. Inspect the mains plug as described in
Formal Visual Inspection. An insulation test should always be carried
g. Inspect the mains cable as described in out before attempting any tests which involve
Formal Visual Inspection. applying mains power to the equipment under
h. Assess the suitability of the equipment for test as it may detect a dangerous insulation
the environment. failure.
i. Where possible, consult the user as to
whether there are any known problems The recommendations given by IET Code of
with the equipment. Practice for In-Service Testing of Electrical
Equipment are as follows:

Note: Special care should be taken where Class I Appliances

equipment is powered from an interruptible ∙∙ Earth continuity test.
power supply (UPS) or has internal battery ∙∙ Insulation resistance test or protective
backup. conductor current test or alternative/
substitute leakage test.
∙∙ Functional checks.
In-Service Tests
The IET “Code of Practice for In-Service Class II Appliances
Inspection and Testing of Electrical Equipment” ∙∙ Insulation resistance test or touch current
recommends a system of periodic inspection test or alternative/substitute leakage test.
and testing, with up-to-date records, as a ∙∙ Functional checks.
means of demonstrating compliance with
the Electricity at Work Regulations 1989. Most
companies and organisations that wish to
comply with the requirements of the Electricity
at Work Regulations 1989 will carry out
in-service tests at intervals determined by risk
assessment.

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 PAT: A PRACTICAL GUIDE

Fixed Equipment or Appliances inspection and testing can be undertaken

during periodic inspection and testing of the
fixed installation. Where equipment could be
subjected to higher use or have a greater risk of
damage, additional formal inspections may be
required.

Appliance Cable Sets

A 3-core appliance cable should be tested as a
Class I appliance and the following tests should
be made:

Fixed equipment or appliances are more ∙∙ Earth continuity.

difficult to inspect and test due to their ∙∙ Insulation resistance.
connection to the fixed wiring of an installation. ∙∙ Wiring polarity check.
This does not mean that only visual inspections
are required for these types of equipment and A 2-core appliance cable should be tested as
they should be subjected to a full combined a Class II appliance and the following tests
inspection and test intervals determined by risk should be made:
assessment.
∙∙ Insulation resistance.
Testing fixed equipment or appliances must ∙∙ Wiring polarity check.
be carried out by a competent person, in
accordance with the specific tests for a
particular class of equipment. The person Note: Seaward portable appliance testers
carrying out the inspection and testing: are equipped with appliance cable tests
that automatically perform all of the
∙∙ must be competent to carry out safe recommended tests, including wiring
isolation procedures, polarity.
∙∙ must be competent to carry out this more
complex arrangement of work,
∙∙ must ensure safe systems of work are
observed at all times,
∙∙ must ensure all inspections and tests are
relevant to the class of equipment.

Where the frequencies of any combined

inspection and testing for permanently fixed
equipment, determined by risk assessment,
are similar to those for the fixed installation,
inspection and testing of the fixed installation,

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Extension leads, multi-way adaptors and

RCD adaptors
Extension leads and multi-way adaptors are
tested as a class I appliance and the following
tests should be performed:

∙∙ Earth continuity.
∙∙ Insulation resistance.
∙∙ Wiring polarity check.

When the extension lead or multi-way adaptor

is fitted with an RCD, the RCD must have a
rated residual operating current (the current
at which the RCD is designed to operate) not
exceeding 30mA.

The IET Code of Practice for In-Service

Inspection and Testing of Electrical Equipment
also recommends that the operation of the
RCD should be checked using RCD test
instrument to determine that the trip time is
within its limits specified in Table A below:

TABLE A

RCD Type Maximum tripping time at Maximum tripping time at 5x

rated current rated current

Portable devices to BS 7071 RCD trip time ≤ 200ms RCD trip time ≤ 40ms

BS EN 61008
RCD trip time ≤ 300ms RCD trip time ≤ 40ms
BS EN 61009

Note: Many Seaward portable appliance testers are equipped with an RCD trip time test for
testing the operation of RCDs in accordance with the recommendations of the IET Code of
Practice for In-Service Testing of Electrical Equipment.

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Testing After Repair Testing Hire Equipment

The IET Code of Practice recommends that The IET Code of Practice does not cover
equipment that has been repaired should be inspection and testing of equipment or
inspected and tested either in accordance appliances that are used for commercial gain
with the manufacturer’s production tests or hire purposes. Equipment hire companies
in-service tests. The decision is based upon the should refer to the Hire Association of
type of equipment and the nature of the repair. Europe (HAE) and Event Hire Association
(EHA) document, HAEEST2012: ‘Guidance on
Class I Appliances Electrical Safety Testing in the Hire Industry‘,
which gives guidance on in-service inspection
∙∙ Earth continuity test. and testing for hire equipment prior to its
∙∙ Insulation resistance test. release to customers/clients.
∙∙ Dielectric strength test.
∙∙ Protective conductor current test. The HAE/EHA Code of Practice recommends
∙∙ Functional checks. that combined inspection and testing should
comprise of some or all of the following:
Class II Appliances
∙∙ Visual inspection.
∙∙ Insulation resistance test. ∙∙ Earth continuity test.
∙∙ Dielectric strength test. ∙∙ Insulation resistance or protective
∙∙ Touch current test. conductor/touch current test.
∙∙ Functional checks. ∙∙ Dielectric strength test.
∙∙ Load (Run) Test.
Testing after repair is performed to ensure that ∙∙ Polarity check.
the repair has not compromised the electrical ∙∙ Functional checks.
safety of the electrical equipment and this
is reflected by the recommended electrical Electrical Tests
tests. For example, the earth continuity test
will demonstrate that all protective earth Earth Continuity
connections have been replaced when the This test is performed on Class I equipment or
appliance is reassembled. Similarly, the mains cables and is used to verify the integrity
dielectric strength test is a useful means of of the connection between the protective
ensuring that all insulating materials has been conductor and all exposed metal parts
correctly reassembled and that the insulation intended to be connected to the protective
on live conductors has not been damaged conductor.
during reassembly, for example, when wires are
trapped or damaged by fixing screws. The IET Code of Practice for In-service
Inspection and Testing of Electrical Equipment
recommends either of the following:

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A continuity measurement with a short When testing equipment with a mains

circuit test current within the range 20mA to cable, the continuity test is made between
200mA all accessible earthed metal parts of the
or equipment and the earth pin of the plug.
A continuity measurement with a test When testing equipment without a mains
current not less that 1.5 times the rating of cable, the continuity test is made between
the fuse and no greater that 25A for a period the earth pin of the mains input socket
of 5 and 20 seconds. and all exposed metal parts. The resistance
measurement should be observed while
flexing the cable and an inspection of the
Note: Some appliances, for example IT flexible cable terminations at the equipment
equipment, may have accessible metal parts and the plug or flex outlet should be made.
which are connected to earth for functional Variations in measured resistance should be
or shielding purposes only. If the high current investigated.
test option above is used, the test current will
flow through sensitive components or wiring The measured resistance should not exceed
not intended to provide a protective earth the values given in Table B below:
connection. Inappropriate use of high test
current may damage the equipment under
test. If in doubt, a low test current should be Note: Normal values for resistance of the
used. protective conductor of the supply cable are
given in Table G (see page 26).

TABLE B

Earth Continuity Reading - Maximum Values

Appliances with a supply cable (0.1 + R) ohm

Appliances without a supply cable 0.1 ohm

3 core appliance mains cables (0.1 + R) ohm

Extension leads, multi-way adaptors and RCD (0.1 + R) ohm

adaptors

Note: R is the resistance of the protective conductor of the supply cable. Refer to table G for
details (page 26).

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 PAT: A PRACTICAL GUIDE

Where possible, it is advisable to test touched during an insulation test.

equipment together with its supply cable. If
the mains cable is not detachable, no practical This may not be suitable for certain types of
alternative exists. appliance. In case of equipment fitted with
mains filters, voltage limiting devices or surge
Care should be taken to ensure that the test protection it may not be possible to obtain a
connections to the equipment under test satisfactory insulation resistance measurement
make clean metal-to-metal contact otherwise with 500V DC test voltage. IT equipment which
contact resistance may introduce significant does not comply with BS EN 60950 may be
errors. damaged by the 500V DC test voltage.

It is possible for Class I equipment to have An alternative/substitute leakage, an insulation

conductive metal parts which are not resistance test at a reduced test voltage
accessible to the operator, accessible metal such as 250V DC or a protective conductor/
parts with protection against electric shock touch current measurement may be more
being provided by double or reinforced appropriate.
insulation or to have ‘unearthed’ metal parts
which are in casual or fortuitous contact with This test should be performed with the
earthed metal. In this case no earth continuity equipment switched ON. Some electronic
test is specified. equipment may contain mains filter circuits
connected between live/neutral and earth.
Insulation Resistance Such devices could cause the insulation
Insulation resistance is measured by applying resistance to be less than specified. The
a test voltage of 500V DC and measuring the manufacturer/supplier must be consulted
resistance. in these cases as to the acceptable value of
insulation resistance.
When testing a Class I appliance the voltage is
applied between both live conductors (phase Insulation Resistance for Heating and
and neutral) and the protective conductor Cooking Appliances
(earth). When testing a Class II appliance, For equipment such as portable cookers the
the test voltage is applied between both live insulation resistance when cold can be very low.
conductors (phase and neutral) and a test Switching on the appliance for a period of time
probe. The test probe should be applied to any drives out any absorbed moisture, enabling
exposed metal parts of the enclosure where more realistic resistances to obtained.
conductive material may have accumulated.
Multiple tests may be required.

Modern portable appliance testers produce

a test voltage which is current limited.
The voltage is not dangerous but could be
uncomfortable. Appliances should not be

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TABLE C Minimum Acceptable Insulation Resistance Values

Class of Construction Minimum Insulation Resistance

Class I heating and cooking equipment 0.3Mohm

With a rating ≥ to 3kW

All other Class I equipment 1.0Mohm

Class II equipment 2.0Mohm

Class III equipment 0.25Mohm

Alternative or Substitute Leakage The test voltage is 50Hz AC and normally in

Measurement the range of 40V to 250V. The test voltage is
Alternative or substitute leakage is measured current limited and so there is no hazard to
using a technique similar to that used when the test operative. As the test voltage has the
measuring insulation resistance. A test voltage same nominal frequency as the mains supply
is applied between both live conductors (phase the leakage paths are similar to those found
and neutral) and the protective conductor when the equipment is in operation. Similarly,
(earth) during Class I test, or, a test probe because the test voltage is not greater than
connected to the equipment enclosure during the nominal supply voltage of the equipment
a Class II test. The resultant current is measured under test measurements are not affected by
and then scaled to indicate the current that transient suppressors, MOVs or other voltage
would flow at nominal supply voltage. limiting devices.

Portable appliance testers automatically make

the necessary connection between the live and
neutral conductors and apply the correct scale
factor to the measured current. The equipment
under test must be switched ON during the
test.

Dielectric Strength Test

This test is also known as the “high voltage
leakage test”, “high pot test” or “flash test” and is
a ‘type of approval test’ or ‘production test’.

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 PAT: A PRACTICAL GUIDE

Test voltages of 1500V AC and 3000V AC are EN 60335 “Safety of household and similar
available on selected Seaward testers that electrical appliances” allows a high voltage
include this test. leakage current of 0.75A/kW with an overall
maximum 5mA. As Seaward testers are
The 1500V AC is applied at the mains plug intended to test equipment with a maximum
of the appliance under test, between the power consumption of approximately 3kVA
protective earth conductor and the live/neutral the pass level defaults to 3mA. Equipment to
conductors connected together. The 3000V BS2769 “Hand held electric motor operated
AC test is applied between the live/neutral tools” requires maximum permitted leakage is
conductors connected together at the mains 0.75mA. The test should be conducted with the
plug and a high voltage test probe applied to unit under test switched ON.
the enclosure of the appliance under test. No
other connection is necessary. Table D defines the test voltages for a range of
appliances.

TABLE D Dielectric Strength Test Voltages

Standard Basic Insulation Supplementary Reinforced

Insulation Insulation

EN 60335 Safety of Household Electrical 1000V 2500V 2500V

Appliances

EN 60065 Audio, Video and Similar 1500V 2500V 2500V

Electronic Apparatus - Safety
Requirements

EN 60950 Safety of Information 1500V 1500V 3000V

Technology Equipment, Including
Electrical Business Equipment

Warning: During flash testing, close The IET Code of Practice does not recommend
proximity to the high level of charge present the use of the dielectric test as an in-service
could cause damage to certain types of test but does state that it may be appropriate
electronic equipment which incorporates after a repair in accordance with the
semi-conductor devices. The advice of the manufacturer’s production or
equipment manufacturer should always be in-service tests, depending on the equipment
sought before testing when such conditions and the nature of the repair.
are suspected.

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SEAWARD

The Hire Association Europe (HAE) and Event for Class I equipment, or from live parts to
Hire Association (EHA) Guidance on Electrical accessible metal parts of the enclosure on
Safety Testing in the Hire Industry includes Class II equipment under normal operating
recommendations and guidance on the use of conditions. This test is an alternative to the
dielectric strength testing. insulation test where the insulation test is
inappropriate. This test will provide evidence of
Preload Check possible deterioration of certain components
Seaward portable appliance testers under load and may indicate that the method
automatically perform a pre-check before of connection of the equipment to the supply
tests which involves applying mains power is inappropriate.
to the equipment under test. This is included
to protect the test person from potential Table E defines the limits for protective
hazards produced by a very low impedance or conductor or touch current.
short circuit being present between LIVE and
NEUTRAL. The test should be conducted with
the equipment switched ON. Note: Should the equipment contain a
mains interference suppression capacitor
Load Test or filter, some residual leakage will be
A load test is not a ‘required’ safety test, measured; this will not necessarily indicate a
however it can provide useful information fault condition.
regarding the operation of the equipment
under test. The portable appliance tester will
apply the supply voltage to the equipment
under test and measure the power Warning: Special care should be taken
consumption in kVA of load current in amperes. during tests where the equipment under
test is energised. Portable tools and rotating
The test is included since a higher power than machines etc. should be rendered safe
expected from the specification may indicate before the complete test sequence begins.
reduced functional efficiency. A significant All such machines should therefore be
change from a previously recorded figure may physically secure and have their cutting,
provide an early warning or bearing failure in grinding, drilling bits etc. removed where
an electrical machine or shorted turns within possible; where guards are provided they
a transformer, both conditions indicating the should be in place.
need for maintenance. Abnormally low power
could be the indication of an open circuit,
ruptured fuse or other form of fault.

Protective Conductor/Touch Current

Measurement
The protective conductor/touch current is
measured from live parts to protective earth

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 PAT: A PRACTICAL GUIDE

TABLE E Protective Conductor/Touch Current Limits

Class of Construction Maximum Permissible Current

Portable or hand-held Class I equipment 0.75mA

Class I Heating appliances 0.75mA or 0.75mA per kW, whichever is

greater, with a maximum of 5mA

Other Class I equipment 3.5mA

Class II equipment 0.25mA

Class III equipment 0.5mA

Frequency of inspection When assessing the risk, the following factors

should be considered:
based on risk assessment
1. The environment.
Guidance on the frequency of testing and/ 2. The users.
or inspection is provided in the IET Code of 3. The equipment class of construction.
Practice and in HSE Guidance Notes such as 4. The equipment type.
‘Maintaining Portable Electrical Equipment in 5. The frequency of use.
Low-risk Environments’. The duty holder should 6. Type of installation methods.
determine the appropriate interval between 7. Previous records.
inspection and testing based on robust risk
assessment. Guidance on the initial frequency of suggested
inspection and test periods is given in the IET
Risk Assessment Code of Practice for In-Service Inspection and
Any risk based assessments are the Testing of Electrical Equipment, and can also
responsibility of the duty holder however a duty be found in the HSE publications HSG107
holder may enlist the services of a competent Maintaining Portable Electrical Equipment
to assist in this process. Risk assessments and INDG236 Maintaining Portable Electric
should be reviewed regularly to ensure that any Equipment in Low-Risk Environments.
control measures are effective and that there
are no changes which may alter the level of The table overleaf appears in the HSE Guidance
risk. If there are any significant changes, the risk Note HSG107 ‘Maintaining Portable Electrical
assessment should be updated. Equipment’ and provides suggested initial
maintenance intervals.

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SEAWARD

TABLE F: Suggested Initial Maintenance Intervals

Maintaining portable electrical equipment HSG107 (3rd. Edition) HSE 2013

Type of business User checks Formal visual Combined inspection

inspection and test

Equipment hire N/A Before issue/after return Before issue

Battery operated equipment (less No No No

than 40 V)

Extra low voltage (less than 50 V AC), No No No

telephone equipment, low-voltage
desk lights

110V equipment Yes, weekly Yes, monthly Yes, before first use on site
then 3-monthly

230V equipment Yes, daily/every shift Yes, weekly Yes, before first use on site
Construction

then monthly

Fixed RCDs Yes, daily/every shift Yes, weekly Yes, before first use on site
then 3-monthly (portable
RCDs monthly)

Equipment site offices Yes, monthly Yes, 6 monthly Yes, before first use on site
then yearly

Heavy industrial/high risk of Yes, daily Yes, weekly Yes, 6-12 months
equipment damage (not construction)

Light industrial Yes Yes, before initial use Yes, 6-12 months
then 6 monthly

Office information technology rarely No Yes, 2-4 years No if double insulated, other-
moved, e.g. desktop computers, wise up to 5 years
photocopiers, fax machines

Double insulated (Class II) No Yes, 2-4 years No

equipment moved occasionally (not
hand-held), e.g. fans, table lamps

Hand-held, double insulated (Class Yes Yes, 6 months - 1 year No

II) equipment, e.g. some floor cleaners,
some kitchen equipment

Earthed (Class I) equipment, e.g. Yes Yes, 6 months - 1 year Yes, 1-2 years
electric kettles, some floor cleaners

Cables, leads and plugs connected Yes Yes, 6 months - 4 years Yes, 1-5 years depending on
to Class I equipment, extension leads depending on type the equipment it is connected
and battery charging equipment of equipment it is to
connected to

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 PAT: A PRACTICAL GUIDE

Note: Cables, leads and plugs connected to Class II equipment should be maintained as part
of that equipment. Cables leads and plugs not dedicated to an item of equipment should be
maintained as individual items as appropriate. Over time, when you look at the results of user
checks, formal visual inspections and portable appliance tests you will notice trends. These may
tell you that you need to look at or test electrical equipment more or less often, depending on
the number of problems being found. If electrical equipment is grouped together for testing at
the same time, you should use the shortest testing interval in the group rather than the longest.
Alternatively, It may be appropriate to group your electrical equipment by testing interval. The
IET Code of Practice has a similar table but with the information presented in a slightly different
manner. In some instances with more detail and specifics, however, the two sets of information
are considered to be consistent with each other.

Record Keeping Step by step

A step-by-step approach would include the
Although there is no legal requirement to keep following:
records of inspection and testing, the HSE
Memorandum of Guidance on the Electricity a. Conduct a survey to identify all portable
at Work Regulations 1989 advices that records and transportable appliances which exist
of maintenance including tests should be kept with the duty holder’s control.
throughout the working life of the equipment. b. Each appliance should be marked
with a unique identification code, cross
In any proceedings for an offence consisting of referencing test results and inspection
a contravention of the EAWR 1989 Rep 4 (4).5 details.
and 8 to 16 inclusive (i.e. those Regulations c. A register of all equipment should then be
requiring “absolute” compliance); Regulation 29 created to include the following details:
states that it shall be a defence for any person
to prove that they took all reasonable steps 1. Identification number.
and exercised all due diligence to avoid the 2. Location in which the equipment is
commission of that offence. kept
3. A description of the appliance.
The most effective method for the duty holder 4. Serial number.
to prove that he “exercised all due diligence” 5. Periods between tests.
etc., is to produce proper records of the 6. Any other details.
measures taken to prevent the accident. Hence
full and accurate records made at the time of Due to the large number of appliances and
testing become essential, and the managed the details that must be recorded a computer
system designed to achieve this must be in database is likely to be the most effective and
place before the accident. efficient method of data collection and storage.

PG 23
SEAWARD

A comprehensive software package, such as a. Unique identifier or asset ID.

Seaward’s PATGuard, will ensure the user to b. Current safety status e.g. PASS or Fail.
set up a detailed database of all items at any c. The date tested.
particular location easily. d. The identity of the test person.

By recording the information outlined in (c) Such information will enable the duty holder to
above working documents can be produced manage this aspect of the overall safety of the
which are a useful aid to proficiency and safety. area within his control. The IET Code of Practice
For example a work schedule can be generated 4th Edition recommends that the date for
grouping products by test date, task sheets can re-testing should not be marked on the label.
be printed providing the person conducting
the tests with a list of all items due for testing, A convenient method of labelling equipment
together with their location, identification may incorporate a barcode. Seaward have a
number etc. range of instruments which can used with a
barcode reader and collect appliance number
Use of Advanced Portable Appliance Testers and test codes without the need for manual
Where advanced portable appliance testers data input. A full range of labels and data
are used, data can be transferred directly from collection accessories are available from
the instrument to the database providing Seaward.
automatic creation or update of records.

In such situations reports of untested

appliances and those which failed the tests can
be produced and submitted to the duty holder
for the appropriate action to be taken, this
insures the investigation is thorough and avoids
oversight.

Action on Completion of Tests

Any equipment found unsafe must
immediately by removed from use, labelled
with its fault and transferred to the repair
facility and the appropriate person informed.

Although there is no requirement in the

Electricity at Work Regulations 1989 to label
equipment, the duty holder may find it useful
to label equipment with the information shown
below to indicate that it has been tested:

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 PAT: A PRACTICAL GUIDE

Data Transfer Between Test Instrument and appliances. Once an earth bond test has been
PC performed the approximate resistance of
the protective conductor can be found and
deducted from the test results to give a more
realistic figure for the resistance of the earth
bonding of the appliance.

For a free 30 day trial of PATGuard 3 visit

www.seaward.com/PG3

Advanced Seaward PAT Testers contain output

ports which allow the tester to be connected
to a PC running PATGuard software. Selected
appliances from various locations can have their
test data sent directly to the PAT (this is called
upload) which after disconnection from the PC
may then be taken to the location where the
appliances are to be tested.

Simply by inputting the appliance number,

the PAT will search the upload memory in an
attempt to identify that particular appliance, If
the appliance is identified the pre-determined
sequence of tests will be suggested to the user.
If this is accepted, the instrument will then
automatically conduct the tests and record the
results.

The advantage of this approach is that it helps

avoid uncertainty as to which tests should be
conducted on a particular appliance.

The table overleaf gives figures for the nominal

resistance of the protective conductor per
metre length and for various lengths of
cable that may be fitted as supply leads to

PG 25
SEAWARD

TABLE G Supply Lead Resistance

Nominal resistance of appliance supply cable protective conductors (cables to BS6500)

Nominal Nominal Length Resistance Max. Max. diameter Approx. No.

conductor conductor (metres) at 20˚C current of individual of wires in
c.s.a. mm2 resistance mΩ carrying wire in conductor
at 20˚C mΩ/ capacity conductor mm
metre A

0.75 26 1.0 26 6 0.21 24

1.5 39
2.0 52
2.5 65
3.0 78
4.0 104
5.0 130

1 19.5 1.0 19.5 10 0.21 32

1.5 29.5
2.0 39.0
2.5 48.8
3.0 58.5
4.0 78.0
5.0 97.5

1.25 15.6 1.0 15.6 13 0.21 24

1.5 23.4
2.0 31.2
2.5 39.0
3.0 46.8
4.0 62.4
5.0 78.0

1.5 13.3 1.0 13.3 15 0.26 30

1.5 20.0
2.0 26.6
2.5 33.3
3.0 39.9
4.0 53.2
5.0 66.5

2.5 8 1.0 8 20 0.26 50

1.5 12
2.0 16
2.5 20
3.0 24
4.0 32
5.0 40

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 PAT: A PRACTICAL GUIDE

Appendix
HSE Guidance notes
HSG13 Electrical Testing
HSR107 Maintaining Portable Electrical Equipment
HSR18 Administrative guidance on the application of the EC ‘Low Voltage Directive’
HSR25 Memorandum of guidance on the Electricity at Work Regulations 1989
PM29 Electrical hazards from steam/water pressure cleaners
PM32 The safe use of portable electrical apparatus
PM38 Selection and use of portable electric handlamps
GS27 Protection against electric shock
GS37 Flexible leads, plugs and sockets.

Codes of Practice
IET Code of Practice for In-service Inspection and Testing of Electrical
Equipment 4th Edition ISBN 978-1-84919-626-0

Hire Association of Europe (HAE) and Event Hire Association (EHA)

document, ‘Guidance on Electrical Safety Testing in the Hire Industry’ HAEEST2012

Legislation

The Health and Safety at Work etc. Act 1974 ISBN 0 10 5437743

The Electricity at Work Regulations 1989 (S.I. 1989 No.635) ISBN 0 11 096635X

The Plugs and Sockets etc. (Safety) Regulations 1987 (S.I.1987 No.603) ISBN 0 11 076603

Contains public sector information licensed under the Open Government Licence v2.0
http://www.nationalarchives.gov.uk/doc/open-government-licence/version/2/

PG 27
SEAWARD

PAT Testers from Seaward

Apollo+ Series
The winning line up of
downloadable PAT testers
from Seaward
Our NEW Apollo+ Series
now comes with improved
functionality and accessories,
including the option of an
external rechargeable battery
pack, extra durable labels, and
the ability to scan and print QR
codes*

Apollo 600+
A multi-tasking PAT tester with
on-board camera.
A multi-tasking and fully customisable PAT
tester with additional health and safety features
and on-board camera for unrivalled record
keeping.

Apollo 600+ includes a universal risk

assessment tool and the ability to store up to
50,000 appliance records, plus 2,000 images -
providing visual evidence of test environments;
perfect for advanced record-keeping in
organisations with high-volume workplace test
and inspection routines.

*does not include Apollo 400+.

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 PAT: A PRACTICAL GUIDE

Apollo 500+
A fast & fully customisable,
versatile PAT tester.
A powerful PAT tester with a built-in PAT
retest calculator and flexible user-configurable
sequences for recording any non-electrical
workplace test or inspection.

The ability to customise a number of settings,

and a large memory to store up to 10,000
appliance records, makes the Apollo 500+ a
versatile and dependable tool for high volume
PAT testing.

Apollo 400+
A simple, no-nonsense PAT
tester.
A straightforward electrical safety tester with
QWERTY keypad for fast data entry and storage
of up to 2,000 appliance records.

Ideal for mid-volume testing in compliance

with IET 4th Edition Code of Practice, the
Apollo 400+ offers easy and efficient data
management with remote data transfer and
USB downloading.

PG 29
SEAWARD

Supernova Elite
A comprehensive dual voltage
PAT with flash test.
∙∙ Tough
Rugged enclosure can withstand the
harshest of environments.
∙∙ Dual Voltage
True dual voltage for testing both 230V
& 110V appliances, whether the tester is
powered by a 230V or 110V supply.
∙∙ Reliable
Proven to be extremely reliable, accurate and
hardworking.

PrimeTest 250+
Handheld, compact and
feature packed to test most
workplace appliances.
∙∙ Accurate and reliable earth continuity
testing
Features Seaward’s unique zap circuit.
Go to www.seaward.com/zap-circuit for more
information.
∙∙ Simple data management
Store up to 999 test records and
downloadable to a PC with a single key press.
∙∙ Plug and print
Print pass and fail labels to Test n Tag Pro
printer via serial cable with no setup.

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 PAT: A PRACTICAL GUIDE

PrimeTest 100
Handheld unit for testing earth
continuity, insulation resistance
leakage with measured test
result values.
∙∙ Accurate and reliable earth continuity
testing
Features Seaward’s unique zap circuit
Go to www.seaward.com/zap-circuit for more
information.
∙∙ Handheld and battery powered
This lightweight tester is extremely portable.
∙∙ Long battery life
Conducts up to 5,000 tests before battery
requires replacing.

PrimeTest 50
Basic Pass/Fail handheld unit
for testing earth continuity
and insulation resistance of
appliances.
∙∙ Simple to use
Easy to use push button operation.
∙∙ Accurate and reliable earth continuity
testing
Features Seaward’s unique zap circuit
Go to www.seaward.com/zap-circuit for more
information.
∙∙ Handheld and battery powered
This lightweight tester is extremely portable.

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SEAWARD

PATGuard 3 Software

PATGuard 3 is a complete TimeManager is an exciting

software solution for recording, software package, now
storing, and reporting on included with PATGuard 3,
test and inspection data and provides clear time
downloaded from your PAT management facilities.
tester.
∙∙ Ideal for companies that mange off-site or
∙∙ Tag records with images as visual evidence remote testing staff and need to manage
and produce professional reports and their business in a time efficient manner.
certificates for total traceability and ∙∙ View the tester’s usage simply and quickly
comprehensive record keeping. with TimeMagager’s graphical data display.
∙∙ Save time by using PATGuard 3 to produce
invoices, schedule retests and upload retest
data to your tester.
∙∙ 25 User configurable electrical test/visual
inspection sequences.
∙∙ Provides clear time management information
with TimeManager 3.

For a free 30 day trial of PATGuard 3 visit

www.seaward.com/PG3

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 PAT: A PRACTICAL GUIDE

Accessories and Services from Seaward

Accessories
Choosing the right accessories will make the job of PAT testing faster and easier. Our unique
range of accessories will help you get the most from your tester. The range includes scanners and
Bluetooth enabled printers, a variety of leads and adaptors, pass/fail labels and verification units.

To see the full range of PAT accessories available, visit www.seaward.com/pataccessories

Training
We offer a number of training courses designed to support those in the PAT testing industry, some
of which are City & Guilds approved. We also offer product training to ensure you get the most out
of your Seaward product.

www.seaward.com/training

Online resources & support

At Seaward we take pride in giving you all of the tools to make your life easier. We have a host of
online resources and technical support features on our website including, FAQs, interactive videos,
helpful how-to guides and an online forum for instant support advice.

www.seaward.com/faqs

Service, calibration & repair

Calibration House takes care of your test and measurement equipment by providing calibration
services (including on-site calibration), service, spares and repairs. Contact us for hassle-free
quotations at competitive prices.

www.calibrationhouse.com

PG 33
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Notes

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 PAT: A PRACTICAL GUIDE

Notes

PG 35
 Seaward, 15 -18 Bracken Hill, South West Industrial Estate,
Peterlee, County Durham, SR8 2SW. United Kingdom

T: +44 (0) 191 586 3511 E: sales@seaward.co.uk

Seaward Group Seaward Group @SeawardPAT Seaward Electronic Ltd.

www.seaward.com Rev 5