The fact is that all electrical installations will require inspection and testing at regular intervals as they will deteriorate with age, the type of use, possible damage, and even any alterations or adaptions by persons not qualified to carry out such work. 

According to the Electricity at Work Regulations 1989, Regulation 621.1 states that "where required, periodic inspection and testing of every electrical installation shall be carried out in accordance with regulations 621.2 to 621.5 in order to determine as far as reasonably practicable, whether the installation is in a satisfactory condition for continued service".

It is very important to note that Regulation 621.2 requires the installation to have a "detailed examination" and that examination is to be "supplemented by appropriate tests". This means that the inspection is more important than testing, which is an additional activity to the inspection. When carrying out an inspection, the person doing so must compare the wiring with BS 7671.

What you cannot do is to assume that because wiring conformed to an earlier edition of the regulations that it is necessarily safe. As an example, until 1966 it was acceptable for Class 1 light fittings not to be earthed, and it was also OK to use a public water pipe as a means of earthing. That is not the case today, so if that is what is found on an inspection it is no longer compliant and must be changed.

Furthermore, the inspector carrying out the inspection has to be a "competent person". Regulation 621.5 of BS 7671 requires: "Periodic inspection and testing shall be undertaken by a skilled person or persons, competent in such work". Any inspector needs to possess a high level of knowledge and experience of the type of installation to be inspected. He or she also has to possess a copy of the current edition of BS 7671, or at the very least have access to one for reference purposes.

An inspector will also need a certain amount of test equipment in order to carry out tests. A multi-function tester will be sufficient for small installations such as domestic premises, but for larger installations more complex equipment will be needed. This has to comply with BS EN 61557 standard and be in good condition. It must also be regularly calibrated.

It is also essential that an electrical inspection condition report makes absolutely clear what has and has not been inspected. For instance, it might be the case that only the ground floor wiring and installations in an office block have been inspected, and the report should make this abundantly clear. This could very well be because the business owner on the ground floor requires an inspection, and that there are different businesses or offices on the upper floors which are not owned by him.

There are codes which the inspector must use on the report. Code C1 is for use where an immediate danger is present such as an exposed live wire. The inspector must inform the client so that immediate action can be taken. Code C2 is for something which is "potentially dangerous", while Code C3 means that an improvement is recommended: for instance, warning labels could be missing.

An Electrical Installation Condition Report is a complete check of your wiring, fuses, switchboards, sockets, and so on, together with anything that is directly wired into the system – i.e. without a plug – such as an electric cooker, heated towel rail, etc.

The unfortunate fact is that electrical wiring systems can and do wear. As with anything else, the more they are used the faster they will wear. They do not need testing as often as portable electrical equipment, but in an industrial situation they should be tested every three years. In other commercial premises you should have an Electrical Installation Condition Report every five years, while in domestic premises it should be every ten years. A report should also be carried out whenever there is a change of occupancy of the premises.