Periodic Electrical Inspection
&
Testing

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Much has been said about the requirements of the Electricity at Work Regulations in relation to Portable Appliance Testing, and the need to have competent qualified electricians carrying out maintenance or new work on electrical installations. What seems to get ignored is the need for Periodic Inspection and Testing of all electrical installations.

The IEE Wiring Regulations (BS 7671) require that Periodic Inspection and Testing of electrical installations is carried out at such intervals as are consistent with the type of installation, its use and operation, the frequency of maintenance, and the external influences upon it.

Sensible time scales, that will give an idea of the sort of thing that is being looked for, are as follows:

Office Buildings :- 5 yearly

Retail Premises :- 3 yearly

Swimming Baths :-Annually

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The main aim of this note is not to persuade you that the Periodic Inspection and Testing has to be done nor to point out the timescales for having it done. With the point made above, I am taking that as read.

The aim is to help you to set about getting it done.

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Extent of the Work

When entering into an agreement for the Periodic Inspection and Testing of a building under your control it is a fundamental requirement that the extent and limitations of the inspection and testing be fully described for the contractor. It is recommended that the following procedures are adopted and that the relevant points be discussed with the contractor prior to completing the agreement documents.

Determine your requirements for inspection and testing and tailor the procedures accordingly.

Agree before commencing the work the amount of down time that can be tolerated and arrange a provisional programme for switching off:

· totally.

· individual areas or distribution boards.

It is important that these times are confirmed immediately prior to the contractor switching off.

As it is neither practical nor possible to inspect all parts of the installation, a sampling process will be employed, normally in the order of 10% of all accessories, lighting fittings and control equipment.

Detail any limitations of the inspection and testing to be carried out and explain that the installation must not be dismantled in any way other than opening equipment covers, and that the building structure must not be disturbed. This means that concealed cables and equipment will not be inspected.

Identify any new parts of the installation that may not need to be included in the work.

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Cost of the Work

If must be realised that it is extremely difficult to place a finite value on work that is, by its very nature, an unknown quantity. There are many factors that can affect the time that may be taken to carry out a proper examination of the installation so it is important that provision is made for the contractor making an extra charge for any unforeseen work, particularly out of hours working, that may arise during the course of the work, to enable a reasonably thorough inspection and test to be conducted and a comprehensive report to be provided.

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Contractor's Reports

On completion of the Inspection a report should be provided by the contractor, detailing, to the best of their knowledge and belief, the condition of the installation, results of all tests carried out, a list of recommendations and a conclusion as to whether the installation is safe to use in its present state. If the conclusion drawn is that the installation is unsafe, then the supply should be switched off and notices placed warning of the danger before the contractor leaves site.

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Practical Guidance

The following is offered as guidance as to what should be requested from the contractor. It should be noted that this guidance is by no means exhaustive, and any special local conditions or requirements should be taken into account when determining the work.

A)

Nature of installation and requirements for test.

The inspection of the installation indicated has been requested because it is Mandatory / Recommended.

B)

The contractor must be advised as to the extent of the inspection and tests to be carried out. These will be either:

Visual Inspection Only; or

Visual Inspection Supplemented By Testing; or

Survey, Visual Inspection Supplemented By Testing

N.B. The test sequence will include testing of every main and sub-distribution board and final sub-circuit.

C)

The following is guidance on the extent of the work that should be done.

Visual Inspection Only

Check for any obvious mechanical damage or deterioration of materials and equipment, exposed cables and live parts, missing covers, fixings, labels and notices etc.

N.B. This procedure will not necessitate switching off the installation.

Visual Inspection Supplemented By Testing

Visual Inspection

Repeat as for Visual Inspection Only but also include a thorough inspection of:

The main switchgear and all distribution boards. These should be inspected for the following:

· Fuses and MCBs are correctly rated for over-current and fault current

· Fuse and switch contacts are clean and have not been over-heating

· Conductor terminations are tight and correctly lugged (if possible)

· Busbar connections are properly made and clamps are tight.

Cables - whenever possible cables should be inspected to ascertain:

· The suitability for the load and operating environment

· The condition of the insulation and protection

· Adequacy of fixings and mechanical protection

· Suitability of glands and shrouds

· Proper use of earthing rings and earth connections

· Any signs of over-heating and damage.

Equipment, accessories and lighting fittings should be inspected for:

· Deterioration due to the atmosphere, mechanical damage, over-heating and adequate fixings.

· Connections of conductors and condition of flexes.

This should include removing light fitting covers, switch plates, socket outlets and covers of equipment.

A sample of approximately 10% of all parts and areas of the installation should be inspected.

N.B. Actual % to be agreed with yourselves.

Testing

The following tests, as prescribed in IEE Guidance Notes, should be carried out where practicable.

Continuity of circuit protective conductors (CPCs) at all metal accessories and equipment within a height of 3.5 metres from floor level, and at 10% of all lighting fittings.

Continuity of all bonding conductors and earth clamps.

Continuity of all ring circuit conductors, including CPOS.

Insulation resistance between live conductors and earth of all circuits collectively, excepting any circuits supplying electronic equipment which may be damaged by the test. These shall be listed separately as not having been tested.

An electrical separation test on all electrically separated circuits.

Polarity at the board and at a 10% sample of all lighting switches and equipment to ensure that switches interrupt only phase conductors.

Earth fault loop impedance (Ze) at the main intake position.

Earth fault loop impedance (Zs) at each distribution board.

Earth fault loop impedance (Zs) test on every final circuit and every socket outlet.

Test all Residual Current Devices.

The resistance of every earth electrode.

Prospective fault current at the main intake position and at every distribution board.

A manual operation test on all MCBs, RCDs, switch fuses and isolators.

Survey, Visual Inspection Supplemented By Testing

As Visual Inspection Supplemented By Testing with the addition of providing information in accordance with IEE Regulation 514-09-01. This should include the provision of distribution board schedules. schematic diagrams and as installed drawings detailing the position of fixed equipment.

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Contact Information

Telephone

+44 (0)1480 471733

FAX

+44 (0)1480 393955

Postal address

1 Avenue Road, St Neots, Cambs. UK. PE19 1LJ

Copyright © 2009 Graeme E Gaskell Services
Last modified: 6 October 2009