Electrical wiring

Electrical wiring is commonly understood to be an electrical installation for operation by end users within a building, an engineered structure or a designated outdoor location. It includes the cabling and associated devices such as switches, distribution boards, sockets and light fittings but does not cover the transmission of electrical power to the installation.

Such wiring is subject to rigorous safety standards for design and installation. Allowable Wires and cables types and sizes are specified according to the circuit operating voltage and electric current capability, with further restrictions on the environmental conditions, such as ambient temperature range, moisture levels, and exposure to sunlight and chemicals. Associated circuit protection, control and distribution devices within a building's wiring system are subject to voltage, current and functional specification.

To ensure both wiring and associated devices are designed, selected and installed so that they are safe for use, they are subject to wiring safety codes or regulations, which vary by locality, country or region. The International Electrotechnical Commission (IEC) is attempting to harmonise wiring standards amongst member countries, but significant 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.

In Australia and New Zealand, the AS/NZS 3000 standard, commonly known as the "wiring rules", specifies requirements for the selection and installation of electrical equipment, and the design and testing of such installations. The standard is mandatory in both New Zealand and Australia; therefore, all electrical work covered by the standard must comply.

In European countries, an attempt has been made to harmonise national wiring standards in an IEC standard, IEC 60364 Electrical Installations for Buildings. Hence national standards follow an identical system of sections and chapters. However, this standard is not written in such language that it can readily be adopted as a national wiring code. Neither is it designed for field use by electrical tradesmen and inspectors for testing compliance with national wiring standards. 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.

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