Portable Appliance Testing - PATS

What is Portable Appliance Testing

The 'Inspection and Testing of In-Service Electrical equipment' (usually referred to as Portable Appliance Testing or PAT), was introduced to enable companies & organisations to comply with the Electricity at Work Regulations. To meet these regulations it is necessary to have in place a program of inspection and electrical safety testing of portable appliances.

Do I need my portable electrical appliances tested?

To comply with the Electricity at Work Regulations all portable electrical appliances should be routinely inspected and tested by a competant person. The regulations apply equally to small companies and the self employed as to the larger organisations.

What electrical equipment needs to be tested?

The regulations cover all items of in-service electrical equipment, this includes all moveable items connected to the mains supply by 13A plugs, industrial plugs or hard wired via a fused connection unit. In addition to being responsible for the safety of their own portable appliances, companies are also responsible for the safety of electrical equipment brought on site by employees and contractors.

How often does it need testing?

The frequency of inspection and testing required will vary depending on the type of appliance, its location and its use.

Please see our frequency of test table for further information.

Acts, Regulations and Directives

The Health and Safety at Work Act 1974 (HSW 1974) Sect 6.1 (c) requires that it shall be the duty of any person who designs, manufactures, imports or supplies any article for use at work to supply adequate information about the use for which the article is designed and has been tested, and about any conditions necessary to ensure that it will be safe when being used, cleaned, set maintained dismantled and disposed of.

The EC "Provision and Use of Work Equipment Regulations 1998" places general duties on employers and lists minimum requirements for work equipment to deal with selected hazards whatever the industry.

The Regulations implement an EC Directive aimed at the protection of workers and the "general duties" will require the need to:

a) Make sure that equipment is suitable for the use that will be made of it.
b) Take into account the working conditions and hazards in the workplace.
c) Ensure equipment is used only for operations for which, and under conditions for which, it is suitable.
d) Ensure that equipment is maintained in an efficient state, in efficient working order and in good repair.
e) Provide equipment that conforms to EC product safety directives.
f) Plus certain other general duties and specific requirements etc.

The words "Work equipment" broadly defines everything from a hand held tool to machines of all kinds.

Method / Procedures

All testing is carried out to the proposed guide lines HSE / IEE PM 32 Each appliance will be given a unique identification number, then:

VISUAL INSPECTION

In practice approximately 90% of all equipment defects are found during a preliminary visual inspection.

(1) The exterior of the equipment will be inspected for:
(i) physical damage.
(ii) signs of overheating
(iii) signs of ingress of liquid or foreign materials.

Particular attention will be paid to possible physical damage at accessible mains components such as switches, fuses and appliance couplers.

(2) All mains and power cords, including interconnecting cords, will be checked for physical damage. All flexible cords showing any sign of damage will be replaced at cost + 20%.

(3) Where re-wireable plugs or appliance couplers are used, their covers will be removed, and (i) terminations and cord grips will be checked for tightness.
(ii) terminations will be checked for correct polarity.
(iii) conductors will be checked for damage or loose strands.

(4) Operator accessible fuses on the outside of the equipment will be checked for correct type and rating. If the equipment manufacturer has specified a particular rating for the plug fuse, this will also be checked. If the manufacturer has not specified a fuse rating for the plug the preferred fuse size will be determined and the correct size fitted, and check that properly manufactured cartridge fuses to British Standards are used.

5) Plugs with none insulated pins will be replaced with British Standards approved Insulated ones.

Fuse Replacement

If the manufacturer has not specified a fuse rating for the plug the preferred fuse size ratings are:

Luminaries	1 amp
Up to 700 watt	3 amp
I T Equipment / Power Tools	5 amp
Above 700 watt	13 amp

CLASSES OF EQUIPMENT CONSTRUCTION

The equipment to be tested will normally be constructed in one of two basic classes, designated Class 1, 2. Constructional methods are summarised below, full details being found in BS2754.

Class 1 equipment will provide the user with two levels of protection. The innermost level is the functional or basic insulation covering live internal parts. The second level of protection is provided by a conductive case, which is earthed. This latter level of protection implies that Class 1 equipment could be a high hazard potential since it relies on the integrity of an electrical connection (the protective conductor or earth).

Class 2 equipment also provides the user with two levels of protection, both levels being provided by insulation. Such equipment is often described as "double insulated" and should carry the appropriate symbol. The first protective barrier is the functional or basic insulation while the outer protective layer is known as the supplementary insulation, which may comprise either of an insulating internal lining to a conductive case or in the majority of instances, form the case itself.

TESTING EQUIPMENT (Seaward: Supernova / Europa / IT1000

ORDER OF TESTS

Perform the detailed visual inspection.
Inspect for any damaged components, (these may typically include plugs, sockets, cords, fuse holder, voltage selectors, switches, neon indicators etc).

FIRST ELECTRICAL TEST

EARTH CONTINUITY

The first electrical tests will verify the integrity of the protective conductor (the earth) and every part of the conductive case which is designed to be earthed. This is a British Standards Type Approval test. (All IT and electronic equipment should be tested at 100mA this is a safe testing voltage – testing at higher values could degrade the electronics) The guide lines are: 1.5 times the design current of the unit under test but need not be greater than 25Amps the resistance should not exceed 0.1 Ohm, but does not include supply cord / test cord.

LIMITS

Standards	Resistance between earth pin on plug to earthed metal parts less supply cord
BS 3456 Household Appliances	(0.1 + R) Ohm
BS 4533 Luminaries	0.5 Ohm including supply cord
BS 2769 Handheld motor operated tools	(0.1 + R) Ohm
BS 415 Electronic and related apparatus	(0.5 + R) Ohm
BSEN 60950 IT equipment	(0.1 + R) Ohm

SECOND ELECTRICAL TEST

INSULATION RESISTANCE

The second electrical test performed is the insulation resistance test. For this test, the PAT testers join together live and neutral and apply a 500v DC voltage between these circuit conductors and earth. Such a test is a requirement of BS2754 "Construction of electrical equipment for protection against electrical shock". This is a British Standards Type Approval test.

Class 2 equipment:- a probe is used to replace the missing earth wire. The probe is placed against the part of the equipment that is normally gripped or touched during use or a part judged most vulnerable to electrical breakdown.

INSULATION RESISTANCE TESTS

Standard	Resistance between live parts and the body (Class1) M/ohms	Resistance between live parts and the body (Class 2) M/ohm
BS3456 Household Appliances	2	7
BS4533 Luminaries	2	4
BS2769 Handheld	2	7
BS415 Electronic and related	2	4
BSEN 60950	2	2

INSULATION RESISTANCE TESTS for High Loaded Heating Elements

Insulation to be tested	Minimum insulated resistance Heating and Cooking
	Up to 3 kW M/Ohm	Over 3.1 kW M/Ohm
Between live parts and earthed accessible metal on class 1	1	3 ÷ rated input in kW
Between live parts and metal parts on the body of class 2	3	3

THIRD ELECTRICAL TEST

LOAD TEST

A Load Test is not required by the Standards Authority but is included to protect the test person from the hazards produced by a very low impedance being present between LIVE and NEUTRAL during the following 'operation test' requiring the tester to determine if it is safe to continue testing if a potentially high current is detected.

FOURTH ELECTRICAL TEST

EARTH LEAKAGE CURRENT MEASUREMENT

A final test will measure the total leakage current from LIVE and/or NEUTRAL to earth under operating conditions. This test is particularly relevant on electronic equipment where 'flash' testing has not been used. Although not a direct substitute for a flash test, the earth leakage test will provide evidence of possible deterioration of certain components under test and may indicate that the method of connection of the equipment to the supply is inappropriate.

Earth Leakage Limits

	BS3456 Household	BS4533 Luminaries	BS7269 Handheld Tools	BSEN60905 IT Equipment	BS4343 Connected to Industrial Socket	Connected to domestic plug and socket
Class 1 Not hand held	mA	mA	mA	mA	mA 10	mA 3.5
Class 1 hand held	0.75	1.0	0.75	0.75
Stationary Class1	0.75 or 0.75/kW			3.5
Class 2	0.25	0.5	0.25	0.25

EXTENSION LEADS

Extension leads should be treated as an appliance and tested in a similar fashion to removable mains IEC leads. They will be given a unique serial number, then:

The following tests are conducted.

(i) Visual inspection Resistance of the earth conductor.
(ii) Insulation resistance testing.
(iii)Continuity of each conductor.
(iv) Polarity of phase, neutral and earth connections.

As the length of the extension cable will have an effect on the earth resistance, it is recommended that the following limits are observed

a 10 meters 1.0mm sq
b 12 meters 1.25mm sq
c 15 meters 1.50mm sq
d 25 meters 2.50mm sq

these limits should not be exceeded unless protected by a 30mA- R.C.D. to BS 7071

“Piggy backing” of extension leads is not allowed

Documentation System

(i) To make a new log of all Portable Appliances.
(ii) Identify all equipment with its own unique number. This should be extended to continue and incorporate sequence numbers already in place.
(iii) Record the test results of all Portable Appliances.
(iv) Each item that passes as safe is given a second label to identify the Company and the appliance re-test date.
(v) Items that are found to be faulty, outside of the normal scope of testing, will have a “ DO NOT USE” label. This failed equipment will be brought to your attention to enable you to make the appropriate decision. We always attempt to leave all equipment operational.
(vi) Individual fail reports are produced.
(vii) Ensure that re-tests are carried out at the required frequency.
(viii) All results can be issued in hard copy and if required on disk, with our read-only system of Seawards Pat Guard for Windows , inclusive.