A ring - Circuit, also called the Ring Final Circuit, German mutatis mutandis Annular current distribution is a common in the UK electrical installation. It serves as part of the low-voltage networks of electricity supplies to households, homes and smaller businesses. The structure is defined by the British Standards as a part of the standard BS 1363 and is strongly affected by the use of British outlets.
The ring circuit was developed in Britain in the years 1942 until 1947. In other countries like Germany, this type of electrical installation is not common.
The ring circuit was motivated by the shortage of copper for electrical cables after the Second World War. Through the use of a ring between the distributor ( engl. Consumer Unit) and the various electrical connections could be used for the same electrical power lower conductor cross-sections, as in the star-shaped installation. The disadvantage is the higher installation costs associated with the installation ring and upon interruption of the ring, the risk of thermal overload.
In older distributors Ring Circuit also repairable fuses (English Rewireable fuses ) are used where the user had in blown fuse elements "patch " the fuse wire. Also, this safety- critical system was originally due to the shortage of materials and is consistently replaced by miniature circuit breakers for new installations.
From the distribution box of go per circuit two strands, which are connected to form a closed ring. Because the individual, possibly distributed over several rooms, wall outlets are connected as shown in the adjacent sketch. Stubs inside the ring, especially in subsequent additions, are common.
In smaller rings conductor cross-sections from 1.5 mm2 with a hedge of 30 A and 32 A are common in newer and larger rings and cable cross-sections of 2.5 mm2 can be used. The wall sockets according to British Standard BS 1363 are individually switched, and the connectors are protected with an internal fuse of 13 amps.