Editing Ring circuit (section)

==Description==
{{Unreferenced section|date=July 2021}}
[[Image:Ring circuit.svg|thumb|right|320px|Diagram of a possible configuration of ring final circuit. [[Consumer unit]] is at bottom left.]]The ring starts at the [[consumer unit]] (also known as ''[[fuse (electrical)|fuse]] box'', [[distribution board]], or ''[[circuit breaker|breaker]] box''), visits each [[domestic AC power plugs and sockets|socket]] in turn, and then returns to the consumer unit. The ring is fed from a fuse or circuit breaker in the consumer unit.

Ring circuits are commonly used in British wiring with socket-outlets taking fused plugs to [[BS 1363]]. Because the breaker rating is much higher than that of any one socket outlet, the system can only be used with fused plugs or fused appliance outlets. They are generally wired with 2.5&nbsp;mm<sup>2</sup> cable and protected by a 30&nbsp;A [[Fuse (electrical)|fuse]], an older 30&nbsp;A [[circuit breaker]], or a [[Europe]]an harmonised 32&nbsp;A circuit breaker. Sometimes 4&nbsp;mm<sup>2</sup> cable is used if very long cable runs (to help reduce [[voltage drop]]) or derating factors such as very thick [[thermal insulation]] are involved. 1.5&nbsp;mm<sup>2</sup> [[mineral-insulated copper-clad cable]] (known as ''pyro'') may also be used (as mineral insulated cable can withstand heat more effectively than normal PVC) though more care must be taken with regard to voltage drop on longer runs.  The protection devices for the fixed wiring need to be rated higher than would protect flexible appliance cords, so [[BS 1363]] requires that all plugs and connection units incorporate fuses appropriate to the appliance cord.