Wiring Accessories Understanding the terms
Jake Green, head of technical engagement with Scolmore Group, briefly discusses two simple terms defined in Part 2: ‘wiring system’ and ‘accessory’ as they are to be understood within BS 7671.
T
he use of language when describing electrical terms matters. Confusion over terms has been the cause of many errors as people seek to interpret what a word or phrase means. Part 2 of BS 7671 is an essential read insofar as understanding what a specific regulation means. It details the specific definitions to be used within the Standard and provides clarity of meaning to ensure that all those involved in electrical installation work are ‘singing from the same song sheet’.
Wiring system
A wiring system is described within Part 2 as: ‘An assembly made up of cable or busbars and parts which secure and, if necessary, enclose the cable or busbars.’
There are other definitions detailed within Part 2 for: 18 | electrical wholesaler February 2023
A prefabricated wiring system is, ‘A wiring system consisting of wiring sections incorporating the means of interconnection designed to allow sections to be connected together to form a given system and incorporating installation couplers conforming to BS EN 61535.’
• •
Flexible wiring systems Prefabricated wiring systems
A flexible wiring system is, ‘A wiring system designed to provide mechanical flexibility in use without degradation of the electrical components.’
“The use of language when describing electrical terms matters. Confusion over terms has been the cause of many errors.”
A wiring system is, therefore, by definition, a combination of elements that when taken together form a wiring system, and it is within that context that any regulation referencing wiring systems must be considered. This combination might be for example, a sheathed and insulated cable clipped directly to a surface or single-insulated conductors within conduit or trunking.
Chapter 52 covers the selection and erection of wiring systems. In addition to any external influences and installation methods, the designer and installer should consider the following: • • • •
Cables and conductors
Connections, terminations, and jointing Associated supports or suspensions
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The enclosures or methods of protection against external influences. (Regulation 520.4)
It is clear therefore, that it is essential for any
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