Electrical wiring (UK)

Electrical wiring in the United Kingdom is commonly understood to be an electrical installation for operation by end users within domestic, commercial, industrial, and other buildings, also in special installations and locations, such as marinas or caravan parks. It does not normally cover the transmission of electrical power to them.

Installations are distinguished by a number of criteria, such as voltage (low, very low, high, etc.), phase (single or 3 phase), nature of electrical signal (power, data), type and design of cable (conductors and insulators used, cable design, solid/fixed or stranded/flexible, intended use, protective materials), circuit design (ring, radial), and so on.

Electrical wiring is ultimately regulated to ensure safety of operation, by such as the Building Regulations, currently legislated as the Building Regulations 2010, which lists "controlled services" such as electric wiring that must follow specific directions and standards, and the Electricity at Work Regulations 1989. The detailed rules for end-use wiring followed for practical purposes are those of BS 7671 Requirements for Electrical Installations. (IET Wiring Regulations), currently in its 17th edition Amendment 3, which provide the detailed descriptions referred to by legislation.

UK electrical wiring standards are largely harmonised with the regulations in other European countries and the international IEC 60446 standard. However there are a number of specific national practices, habits and traditions that differ significantly from other countries, and which in some cases survived harmonisation. These include the use of ring circuits for domestic and light commercial fixed wiring, fused plugs, and for circuits installed prior to harmonisation, historically unique wiring colours.

The standard wiring colours in the UK are (as of 2006^[update]) the same as elsewhere in Europe and follow international standard IEC 60446. This colour scheme had already been introduced for appliance flexes in the UK in the early 1970s, however the original colour scheme recommended by the IEE for fixed wiring was permitted until 2006. As a result, the international standard blue/brown scheme is as of 2006 found in most appliance flexes. In fixed wiring, the blue/brown scheme is only found in newer (post-2004) installations, and the old IEE black/red scheme is likely to be encountered in existing installations for many more decades.

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