CONTENTS

What's it all about?

Suggested procedures

The formal visual inspection

More visual considerations

The Electronic Tests

Glossary of terms

Further references

Web site links for PAT testing training courses

Sample record form (App A)

Suggested retest intervals (App B)

Fuse rating guide

Portable Appliance Testing

The Electricity (Factories Act) Special Regulations 1908 & 1944

Have been replaced by:

The Electricity At Work Regulations (1989)

These came into force on 1st. April 1990

If they believe the regulations are not being complied with inspectors are authorised to issue a prohibition notice with immediate effect. This would prevent any further work from taking place on the site. An improvement notice would be issued, and if the requirements of this were not complied with then the case would become the subject of a prosecution.

Maximum penalties of fines up to £5000 and/or up to six months imprisonment are in the event of a successful prosecution under any Health & Safety statute.

The Health & Safety at Work Act 1974 has allowed for penalties up to £20,000 fines since 1992

Offences heard by the Crown Courts have unlimited fines with a possible two year prison sentence.

The surest way to enable yourself to demonstrate that you are taking the regulations seriously, is have in place a record-keeping system which is properly maintained. This may be electronic or paper based, and should show a history of all PAT Testing activity.

T

his manual is designed to enable people who have not received any formal training in electrical work, to carry out visual inspection and possibly electronic testing, of portable appliances, and assess the risk of danger to the user of that appliance.

It must be stressed that visual inspections, without dismantling will not capture every potential defect. This is why, in addition to regular visual inspections appliances MUST receive a full electronic test using a purpose designed PAT meter. Having said this however, it should be borne in mind that, in general, over 85% of faults are discovered during the visual inspection stage.

In the workplace it is a legal requirement that a system of preventative maintenance exists which is “effective in preventing any appliance from becoming a danger to any person”.

Regulation 4(2) States:

"As may be necessary to prevent danger, all systems shall be maintained so as to prevent, so far as is reasonably practicable, such danger."

To this end the person or persons using the appliance should be able, with suitable training, to recognise visual signs that any appliance is not in sound condition.

Types of equipment covered includes

Portable Appliances:

An appliance which is intended to be moved while in operation or an appliance which can easily be moved from one place to another while connected to the supply, e.g. toaster, food mixer, vacuum cleaner.

Transportable Equipment:

This is equipment which is either:

18kg or less in mass and not fixed, e.g. Electric heater, or

Equipment with wheels, casters or other means to facilitate movement by the operator as required to perform its intended use.

Hand-held Appliances or Equipment:

This is portable equipment intended to be held in the hand during normal use, e.g. hair dryer, drill, soldering iron, kettles.

Secondary equipment or appliances:

This equipment has a mass exceeding 18kg and is not provided with a carrying handle, e.g. refrigerator, washing machine.

Extension Leads:

These should use three core cable even if used to feed a class 2 appliance.

Extension Leads should be tested as for class 1 appliances but should additionally include a polarity check.

It is recommended that the maximum length of extension leads should be limited to the following:-

Lead cross sectional area (sq mm) Maximum Length

25. 12 metres

50. 15 metres

50. 25 metres

All extension leads should be used in conjunction with a 30mA RCD

New Equipment:

There do not appear to be any set rules relating to new items which are brought onto the site.

The most widely practiced procedure appears to be that new items are given only a visual inspection an then recorded in the system so that when they are a year old they are marked for full testing. Traditionally this was adopted for fear that testing by an agency other than the manufacturer may invalidate any existing warranty.

However, it may be considered that the possibility that the item may have been damaged in storage or delivery, or stored in an unsuitable environment might be grounds for full testing before issue to a user.

Another consideration of course is that in the event of a fault, the warranty would cover the appliance - but not the user

SUGGESTED PROCEDURES

T

he usual practice, if the site is large, is to circulate a form onto which the details of each item are entered by the manager of each department. This form can then form the basis of a paper or electronic system as required. A suitable form is reproduced in appendix A. and may be copied if required.

If the site is small and there are few items to keep track of, it is still probably wise to maintain records of some sort. It would, for instance provide a check that no items were missed. Also items imported onto the site would be identifiable due the labelling system.

Also if your system provided evidence of very few faults being identified, this might be justification for extending the period of time between tests.

The normal approach is for each appliance to be numbered, and this is the appliance number that is entered on the record card and the label, which is to be attached to the appliance. If a serial number is also evident on the appliance then this can be useful for identification purposes, but don't rely on every appliance having a manufacturer's serial number easily seen.

The Class section of the form refers to whether the appliance is Class 1 or Class 2. This will be explained in the section under check procedures. For the visual check there is only one part of the form to complete, the others are completed at the time of the electronic test which often, but not always has a longer retest interval than the visual.

Labels can be purchased from several sources, and these days show the date of the next test due as well as the date the item was last tested. The purpose of showing the date of the next due test is for the benefit of users of the appliance.

Also bar coded labels are becoming popular, particularly when there are large numbers of appliances and electronic systems are favoured. Bar coding also helps maintain uniformity of tests applied and meaningful comparison of results.

Frequency of testing

Having completed all the forms, a decision must be made regarding the frequency of testing.

Appendix B gives the suggested retest intervals for various items.

This can be used as an initial guide, but experience may, in the fullness of time, indicate that there is a need to modify the programme according to the number and type of faults found. Other factors to bear in mind when considering retest intervals include:

1/ Working environment

(Dampness, Dust, Likelihood of mechanical damage)

2/ Whether equipment is hand held

3/ Age and general condition of the equipment

4/ Potential for misuse

5/ Manufacturers recommendations

6/ Modifications which may have been made to the equipment

It should be noted that on building sites or other harsh environments any programme of planned maintenance should be supplemented by a daily visual inspection of the plugs and leads of all hand-held tools.

THE VISUAL INSPECTION

Appliances are (for our purposes) either Class 1 or Class 2. The difference is as follows:

Class 1 Appliances use a Circuit Protective Conductor or Earth wire.

This means that this earth wire is connected to any exposed metal parts of the appliance. Hence if the basic insulation fails the user is protected by the fact that the exposed parts of the appliance cannot become electrically charged above earth potential. Modern installations would detect this failure and immediately operate an RCD to interrupt the supply, whereas on older installations a fuse should blow in this situation. (RCD's protect people whereas Fuses protect circuits).

It is essential therefore that the condition of the earth wire is sound, and the earth bonding test is designed to check this.

It is also recommended that when fitting or removing plugs and sockets the earth lead should be wired first and removed last.

Class 2 Appliances however, do not use this Earthing technique, so the mains plug will be connected to only two conductors, neutral and phase (Live).

Appliances designed to operate without an earth connection will be constructed with supplementary insulation in addition to the basic insulation provided in Class 1 appliances. Appliances designed to operate in this manner will (or should) be marked by the manufacturer with the "double insulated" sign. (Two squares, one inside the other).

As far as the visual inspection is concerned, the procedure for Class 1 and Class 2 items is similar, except that inspection of a Class 1 appliance should visually assess the integrity of the earth or "CPC" connection.

The Formal Visual Inspection

Although referred to as a visual inspection, there are many instances when other human senses will alert the QTO (Qualified Testing Officer) to a potential or actual fault condition. Overheating can felt, arcing may be seen or heard or even smelt. So be aware that all senses are in fact useful and none should be ignored. Also the person inspecting the appliances has a duty under the Health & safety at Work Regulations to clearly label machinery with guards missing, even if that machinery is electrically safe.

1/ The initial inspection should be to inspect the casing of the appliance for deterioration or damage. All covers should be intact and in place. There must be no holes into which it is possible to insert a finger and possibly touch live areas or components.

2/ Next look at the cable. Taped joins are not acceptable. No cuts or

other damage is allowed except perhaps for very light scuffing of the outer casing in some situations, but even then the outer casing must not be worn through to show the insulation of the conducting wires within.

In the case of bedside or table lamps special attention should be paid to any in-line switches which may be employed. Older examples of these often have ineffective or non-existent cable clamps. Also twisted joints in the cable can often be pulled out of the switch casing, particularly if the switch acts on one conductor only. In these cases the unswitched conductor is often cut to facilitate excess length removal and the end result is seldom truly satisfactory.

3/ Connecting plugs and sockets should be considered next.

It is necessary to remove the covers to these if a meaningful assessment is to be made. Look for the following:

a: That the insulation of the individual conductors is not damaged.

b: The individual conductors themselves are not damaged. (Strands are

sometimes damaged when removing insulation leaving only a few strands to carry the current drawn by the appliance)

c: The individual conductors MUST be connected to the correct terminals.

Green / Yellow to the Earth Terminal

Blue to the Neutral Terminal

Brown to the Live Terminal

d: The individual conductors must be cut to the correct length with

insulation right up to the terminal. Also the CPC or Earth lead should have more slack than the other two so that if the lead is pulled it breaks away last.

e: The cord grip must be effective and operating on the outer sheath of

the cable.

f: The fuse must be of a suitable type and the correct rating.

(See Appendix C)

g: The cover of the plug / socket must be properly fitting and secure.

h: The plug pins must not be bent or distorted and should be of

the modern plastic half sheathed insulated type.

Since February 1995 it has been a requirement that virtually all electrical equipment manufactured in or imported into the United Kingdom will be supplied complete with a suitably fused 13Amp plug.

OTHER CONSIDERATIONS

Whilst at this stage your visual inspection may appear to be complete, there are a few other points to consider before giving the final OK. If the appliance has been checked in the position where it is normally used check also the following:

i: Cables are not left in a dangerous position where they may be damaged

by other furniture or trodden on.

j: The plug or mains switch are easily accessible and not hidden or

blocked by the appliance.(It is generally recommended that power

sockets are labelled with instructions regarding where to find the

main circuit breaker controlling them)

k: There is adequate space around the appliance and the ventilation

slots are not blocked by files, folders or other items which should

have their own storage area.

l: Plants, cups etc are not placed on top of the appliance inviting the

spillage of liquid into the item and causing danger.

m: Appliances should not be located where it is necessary to place a

strain or excessive bend in the supply cable.

n: All covers should be properly fitted so as to prevent user contact

with internal components or wiring.

o: A final check should be made for evidence of overheating.

Eg discolouration or distortion of plastic covers.

p: Conditions and working environment should be checked for suitability,

with special regard for dampness, water leakage, humidity etc.

THE ELECTRONIC TESTS

A

decision needs to be made whether it is viable to have a member of staff make these tests, or if an outside specialist needs to be brought in. First it must be realised that any person may be regarded as "competent" provided suitable training ensures "possession of the necessary theoretical knowledge and practical experience considered appropriate for that person to assess the safety criteria for a particular situation."

In many organisations an opportunity exists to encompass this necessary activity within the job description of an existing employee. One immediate advantage of this would be that if necessary, equipment or appliances could be assessed immediately, without the need to call in an outside contractor.

Equipment necessary is available from most electrical wholesalers and varies widely in cost and complexity.In practical terms however, to test your own equipment on site would need only a basic test set, and these are easy to use and generally do not need any interpretation of results as a simple pass/fail indication is used.

The picture above shows a typical test set which is adequate for most situations. These are available for a couple of hundred pounds, and these usually indicate pass/fail as well as actual voltage or current readings.

What Tests to do?

Earth Bonding Test:

This is used on Class 1 Appliances. (The ones that use a three core cable). The test is usually carried out for only a few seconds, at a low voltage (less than twelve) using a test current which equates to twice the value of the fuse rating for the appliance. For this reason this test must NEVER be used on IT Equipment, as it is possible to cause damage. Instead use the Earth screen test following.

Whilst applying this test it is usual to flex the lead to highlight any fractures or poor connections.

During the Earth Bonding Test high currents flow, so make sure that the earth clip connected to appliance casing is a particularly secure contact. Otherwise arcing could occur with subsequent damage to the appliance casing.

Earth Screen Test: This test also tests the integrity of the earth connection of the equipment, but as this uses very low voltages and current it is suitable for use with IT and other sensitive equipment. Typical values might be 100mv at up to 100mA.

Insulation Test: For this test the test set will connect together the live and neutral pins of the appliance mains plug, and apply 500volts(dc) between this connection and the earth pin of the appliance. Hence the Earth Bonding or Earth Screen test should be carried out and passed first.

Class 2 Appliances with no earth connection within the mains plug it is usual to connect a specially provided probe to the casing of the appliance whilst carrying out this test.

The usually accepted pass levels are for

Class 1 equipment not less than 2Mohms, and for

Class 2 Equipment not less than 7Mohms.

Note: Class 1 heating appliances with a rating above 3KW can be considered as OK with insulation readings down to 0.3 MOhms.

Some operators now regard these as ideal figures to be regarded as suitable for new equipment, and accept slightly lower figures for “in service” appliances. In practice much higher figures are usually encountered.

I.T. Equipment not manufactured to BSEN 60950 does not carry a requirement for this standard 500volt insulation test due to the possibility of damage. In this case if you have later generation PAT Tester it may provide a 250 volt DC insulation test you can use instead.

This will protect internal spike arresters and other suppressors used in the power supplies of some of this type of equipment.

Some other equipment containing suppressors may also fail the standard 500volt insulation test, although they are perfectly sound. Filtered extension leads for use with computers for example fall into this category. However these days manufacturers usually supply this information by labelling. If equipment falls into this category and you have a modern PAT Tester then you can use the “touch current” test instead. This will use the normal supply voltage to the appliance and the “touch current” must not exceed:

Portable/Handheld Class 1 <0.75mA

Class 1 Heaters 0.75mA/kWatt up a maximum of 5mA.

Other Class 1 <3.5mA

Class 2 <0.25mA

Flash Test: Most operators reserve this test for leads for fear of causing damage to internal components such as suppression capacitors. It is sometimes used on equipment which has undergone a complete rebuild or renovation. It is then considered useful as a check after re-assembly that no cables have been trapped or damaged by fitting the equipment casing.

Never apply this test to electronic or IT equipment. A nominal test voltage is 1.5Kv for Class 1 and 3.00Kv for Class 2 is used. The test should only be used with extreme caution, and with particular regard for the safety of testing staff and any bystanders.

Load Test: This is not a required measurement although it can be useful to prove that an appliance actually works. Also if the run load current is recorded that record can be used to spot early signs of impending failure. ( eg: A motor with bearings starting to seize will result in higher load current as the defect worsens)

Remember that when this test is applied the appliance will start up. So in the case of power tools or anything with moving parts make sure that no damage or harm will be caused.

Some test sets will first check that the amount of current drawn will not be excessive before the test proper. Some will measure the current drawn and display or print the information. However your test set handles it the test can save embarrassment being caused by passing an appliance which does not actually work.

Leakage Test: During the Load test above it is usual for most test sets to measure the current flowing through the earth lead of the appliance.

Lead Tests: Most testers will incorporate some test designed to check extension or IEC leads. These tests will include most of the above as well as continuity and polarity checks. In the case of two core leads, test them as a class 2 appliance.

Lead lengths should not exceed the following:

1.25mm leads 12 metres

1.5mm leads 15 metres

2.5mm leads 25 metres

ANY lead exceeding those lengths should be used in conjunction with an RCD rated at 30mA

Very long leads will probably fail the 0.1ohm limit for the earth test due to the resistance of the lead so some simple arithmetic will be required.

Csa sqmm	Nominal resistance mOhms/metre	Maximum current Amperes
0.75	28.00	6.00
1.00	21.50	10.00
1.25	17.50	13.00
1.50	15.00	15.00
2.50	9.00	20.00

CAUTION: Throughout the testing procedure it is important not to touch the appliance. High voltages are used and care must be exercised.

There does not appear to be any statutory definition of a competent person. However for practical purposes a person may be considered to be competent if that person is

“in possession of the necessary theoretical knowledge and practical experience considered appropriate for that person to assess the safety

criteria for a particular situation”.

This manual has attempted, whilst avoiding all the "bells and whistles" to provide the information required to carry out the formal visual inspection of electrical appliances so as to assess their safety. As has been stated earlier internal faults may not be evident by a purely visual check. Therefore if there is any reason to suspect the condition of an appliance, or if any appliance has been the subject of a repair, then that appliance should be made the subject of a full electronic test carried out by a suitably trained person using a purpose built Portable Appliance Tester. There is a wide range of these instruments available from most electrical wholesalers. Although there are some very sophisticated (and expensive) models available, simpler versions are

usually perfectly adequate, come with complete instructions and require no interpretation of results sometimes required from the professional range. Most have their own set of instructions regarding how to download test results to a PC. Therefore no attempt has been made to include this aspect of the work, as it would not be practical to adequately cover all types of test instrument and software combination out there.

IMPORTANT:

Before checking cables , plugs etc. always check that equipment is unplugged. Also be aware that even when unplugged voltage may still remain, particularly when dealing with some types of equipment. (eg UPS devices or appliances containing capacitors)

GLOSSARY of TERMS

Basic Insulation:

Insulation applied to live parts to provide basic protection against electric shock and which does not necessarily include insulation used exclusively for functional purposes.

Class I Equipment:

Equipment in which protection against electric shock does not rely on basic insulation only, but which includes means for the connection of exposed-conductive-parts to a protective conductor in the fixed wiring of the installation.

Class II Equipment:

Equipment in which protection against electric shock does not rely on basic insulation only, but in which additional safety precautions such as supplementary insulation are provided, there being no provision for the connection of exposed metalwork of the equipment to a protective conductor, and no reliance upon precautions to be taken in the fixed wiring of the installation.

Class III Equipment:

Equipment in which protection against electric shock relies on the supply from a separated extra-low voltage source, such as an isolating

transformer to BS 3535.

Double Insulation:

Insulation comprising both basic insulation and supplementary insulation.

Earthing:

The act of connecting the exposed-conductive-parts of electrical equipment to the mains earthing terminal of an electrical installation.

Supplementary insulation:

Independent insulation applied in addition to basic insulation in order to provide protection against electric shock in the event of a failure of basic insulation.

FURTHER REFERENCES

http://www.iee.org.uk/publish

Code of Practice for in-service inspection and testing of electrical equipment

IEE ISBN 0-85296-776-4

Maintaining portable and transportable electrical equipment

HS (G) 107 ISBN 0-7176-0715-1

Maintaining portable electrical equipment in hotels and tourist accommodation:

IND(G)164L HSE 1994 ISBN 0 7176 0718 6

Maintaining portable electrical equipment in offices and other low-risk environments:

IND (G)160L HSE 1994 ISBN 0 7176 0719 4

Memorandum of guidance on the Electricity at Work regulations 1989 (EAW memorandum)

HS(R)25 HSE 1994 ISBN 0 11 883963 2

A guide to the Health & Safety at Work Act 1974L1 HSE ISBN 0 7176 0441 1

Management of Health & Safety at Work Approved Code of Practice

L21 HSE 1992 ISBN 0 7176 0412 8

The Provision & Use of Work Equipment Regulations 1992

SI 1992/2932 HMSO ISBN 0 11 025849 5

http://www.hse.gov.uk/pubns/elecindx.htm

HSE GUIDANCE NOTES:

HS(G)13 Electrical Testing

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

WEB SITE LINKS FOR PAT TESTING TRAINING COURSES

http://www.firststopsafety.co.uk

http://www.electraspec.co.uk

http://www.the instrumentplace.co.uk

http://www.northfieldtraining.co.uk

http://www.pat-services.co.uk

App A: Appliance Test Record

Company:

Department:

Location:

Appliance description:

Make: Model: s/n:

Class 1, 2, 3. Wattage:

P= Pass F= Fail N= not Applicable

Date	Earth	Insulation	Flash	Load	Leakage	Initials

APPENDIX B

Suggested initial retest frequency for Portable Appliance Testing

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Construction Sites

110 or 240volt equipment:

Class 1: Formal visual: Monthly Full Test: 3 Monthly

Class 2: Formal visual: Monthly Full Test: 3 Monthly

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Industrial (Including kitchens)

Stationary and IT Class 1: Formal visual: Annually* Full Test: Annually

Equipment

Class 2: Formal Visual: Annually Full Test: 2 yearly

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Offices and Shops

Class 1: Formal Visual: Annually* Full Test: 1 - 2 Years

Class 2: Formal Visual: Annually Full Test: Not Required

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Hotels

Class 1: Formal Visual: Annually* Full Test: 1 - 2 Years

Class 2: Formal Visual: Annually Full Test: Not Required

--------------------------------------------------------------------------------Schools

Class 1: Formal Visual: Annually** Full Test: Annually

Class2: Formal Visual: Annually** Full Test 2 Years

--------------------------------------------------------------------------------

Areas or Equipment to which the Public have access

Class 1: Formal Visual: 3 Monthly Full Test: Annually

Class 2: Formal Visual: 3 Monthly Full Test: 2 Years

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Notes:

* = Frequency should be reduced to 6 monthly for hand-held appliances

** = Frequency should be reduced to 3 Monthly for hand-held Appliances

App C: Fuse ratings guide:

Although most mains plugs are fitted with a 13Ampere fuse when purchased, The following should be used as a guide regarding the rating of the fuse used

For any particular appliance:

Appliances up to 500 watts: use a 3 Ampere fuse

Appliances between 500 and 1000 Watts:(1Kw) use a 5 Ampere fuse

Appliances over 1000 Watts:(1.00Kw) use a 13 Ampere fuse

Although in recent times it has become common practice to use only two fuse

Ratings:-

Appliances up to about 700watts use a 3 Amp fuse

Appliances over 700 watts use a 13 Amp fuse

When fitting, the cable grip should act upon the outer sheath of the cable and

not the individual conductors.

The GREEN or GREEN & YELLOW cable should be connected to the E or Earth terminal. If possible more slack should be left in this conductor than the other two, so that if the cable is pulled too severely it will break off last.

The BLUE conductor should be connected to the N (Neutral) Pin

The BROWN (or RED) conductor should be connected to the L (Live) Pin

With all connections care should be taken not to allow loose strands of wire

To remain outside of the terminals when the wiring is completed.

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