Electrical code

Associated circuit protection, control and distribution devices within a building's wiring system are subject to voltage, current and functional specification.

The International Electrotechnical Commission (IEC) is attempting to harmonise wiring standards amongst member countries, but large variations in design and installation requirements still exist.

Wiring installation codes and regulations are intended to protect people and property from electrical shock and fire hazards.

They are usually based on a model code (with or without local amendments) produced by a national or international standards organisation, such as the IEC.

By contrast, national codes, such as the NEC or CSA C22.1, generally exemplify the common objectives of IEC 60364, but provide specific rules in a form that allows for guidance of those installing and inspecting electrical systems.

NF C 15-100 (fr) is used for low voltage installations in France The VDE is the organisation responsible for the promulgation of electrical standards and safety specifications.

BS 7671 is also used as a national standard by Mauritius, St Lucia, Saint Vincent and the Grenadines, Sierra Leone, Singapore, Sri Lanka, Trinidad and Tobago, Uganda and Cyprus.

Although the US and Canadian national standards deal with the same physical phenomena and broadly similar objectives, they differ occasionally in technical detail.

As part of the North American Free Trade Agreement (NAFTA) program, US and Canadian standards are slowly converging toward each other, in a process known as harmonisation.

[11][12] In the UK it is fairly common practice to use three-core cable with three-phase coloured insulation for part of the wiring of two-way lighting switches.

To avoid confusion the accepted practice is to add coloured sleeves to the ends in brown or blue as appropriate to communicate how the wires are being used.

[13] The United States National Electrical Code requires a bare copper, or green or green/yellow insulated protective conductor, a white or grey neutral, with any other colour used for single phase.

Prior to the adoption of orange as the suggested colour for the high-leg in the 1971 NEC, it was common practice in some areas to use red for this purpose.