London Electrical Inspection & Testing

Visual Inspections

Joints and Connections

It is not practicable to inspect every joint and termination in an electrical installation, nevertheless a sample inspection is made. An inspection is made of all accessible part of the electrical installation e.g. switchgear, distribution boards, and a sample of luminaire points and socket-outlets to ensure that all terminal connections of the conductors are properly installed and secured. Any signs of overheating and conductors, terminations or equipment will be thoroughly investigated and included in the Report.

Conductors

The means of identification of each conductor, including protective conductors, will be verified. The deterioration of, or damage to, conductors and their insulation and their protective coverings, if any, will be noted.

NB. Cables coated in black- rubber were phased out in the 1960s or cables coated in lead or fabric are even older and may need replacing (modern cables use PVC insulation).

Flexible cables and cords

Where a flexible cable or cord forms part of a fixed wring installation, the inspection will include:

the examination of the cable or cord for damage or defects
examination of the terminations and anchorages for damage or defects
the correctness of its installation with regard to additional mechanical protection, heat resistance sleeving, etc.

Accessories and Switchgear

It is recommended that a random sample of a minimum of 10 per cent of all switching devices is given a thorough internal visual inspection of accessible parts to assess their electrical and mechanical condition.

Protection against Thermal Effects

The presence of fire barriers, seals and means of protection against thermal effects will be verified.

Protection against Direct and Indirect Contact of live parts

The means of protection against contact with live parts by means of SELV, direct contact and indirect contact will be verified.

Protective Devices

The presence, accessibility, marking and condition of devices for electrical protection, isolation and switching will be verified. It should be established that each circuit is adequately protected with the correct type, size and rating of fuse or circuit-breaker. The suitability of each protective and monitoring device and its overload setting will be checked.

Marking and Labeling

The labeling of each circuit will be verified. Notices or labels are required at the following points and equipment within an installation:

at the origin of every installation
where different voltages are present
earthing and bonding connections
Residual Current Devices (RCD's)
where non-standard colours are used

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