Section 1: Design and installation

  1. Section 1

    Section 1

    General

    1.1 Electrical installations should be designed and installed in accordance with BS 7671:2008 incorporating Amendment No 1:2011.

    Provision of information

    1.2 Sufficient information should be provided to ensure that people can operate, maintain or alter an electrical installation with reasonable safety. The information should comprise items listed in BS 7671 and other appropriate information including:

    a. electrical installation certificates or reports describing the installation and giving details of the work carried out

    b. permanent labels, for example on earth connections and bonds, and on items of electrical equipment such as consumer units and residual current devices (RCDs)

    c. operating instructions and logbooks

    d. for unusually large or complex installations only, detailed plans.

    Functionality requirements

    1.3 Part P of the Building Regulations covers the safety of electrical installation work; it does not cover system functionality. Other parts of the Building Regulations and other legislation cover the functionality of electrically powered products such as fire alarm systems, fans and pumps.

    New dwellings

    1.4 Wall-mounted socket-outlets, switches and consumer units in new dwellings should be easy to reach, in accordance with Part M of the Building Regulations (Access to and use of buildings).

    NOTE: Approved Document M recommends that in new dwellings only, switches and socket- outlets for lighting and other equipment should be between 450mm and 1200mm from finished floor level. Approved Document M does not recommend a height for new consumer units. However, one way of complying with Part M in new dwellings is to mount consumer units so that the switches are between 1350mm and 1450mm above floor level. At this height, the consumer unit is out of reach of young children yet accessible to other people when standing or sitting.

    New dwellings formed by a change of use

    1.5 Where a material change of use creates a new dwelling, or changes the number of dwellings in a building, regulation 6 requires that any necessary work is carried out to ensure that the building complies with requirement P1. This means that in some cases the existing electrical installation will need to be upgraded to meet current standards.

    NOTE: If existing cables are adequate, it is not necessary to replace them, even if they use old colour codes.

    Additions and alterations to existing electrical installations

    1.6 Regulation 4(3) states that when building work is complete, the building should be no more unsatisfactory in terms of complying with the applicable parts of Schedule 1 to the Building Regulations than before the building work was started. Therefore, when extending or altering an electrical installation, only the new work must meet current standards. There is no obligation to upgrade the existing installation unless either of the following applies.

    a. The new work adversely affects the safety of the existing installation.

    b. The state of the existing installation is such that the new work cannot be operated safely.

    1.7 Any new work should be carried out in accordance with BS 7671. The existing electrical installation should be checked to ensure that the following conditions are all satisfied.

    a. The rating and condition of existing equipment belonging to both the consumer and to the electricity distributor are suitable for the equipment to carry the additional loads arising from the new work.

    b. Adequate protective measures are used.

    c. The earthing and equipotential bonding arrangements are satisfactory.