Additions and alterations
The Minor Works Certificate is intended to be used for additions and alterations to an installation that do not extend to the provision of a new circuit. Examples include the addition of socket-outlets or lighting points to an existing circuit, the relocation of a light switch etc.
It may also be used for the replacement of equipment such as accessories, motors or luminaires, but not for the replacement of distribution boards or similar items. Appropriate inspection and testing, however, should always be carried out irrespective of the extent of the work undertaken.
Every addition or alteration to an existing installation must comply with the current edition of BS 7671 and must not impair the safety of the existing installation and the relevant inspection and testing requirements of Chapter 64 also apply to additions and alterations. This applies especially to the replacement of a distribution board or consumer unit. In order to verify that the addition or alteration to an electrical installation complies with BS 7671, the relevant parts of an existing installation must be inspected and tested to confirm the safety of the addition or alteration, including for example:
- (a) circuit ratings;
- (b) circuit conductor sizes;
- (c) means of earthing;
- (d) protective conductor continuity; and
- (e) earth fault loop impedance.
Whilst there is no obligation to inspect and test any part of the existing installation that does not affect and is not affected by the addition or alteration, any departures or non-compliances observed are required to be noted in the ‘Comments on existing installation’ section of an electrical installation certificates (single-signature or multiple-signature) or minor electrical installation works certificates.