The radial power circuit feeds a number of sockets of FCUs (Fused Connection Units) but, unlike the ring circuit, the cable on the radial circuit terminates at the last outlet. FCUs are sockets to which applances are permanently wired and which have a fuse housed inside the unit. FCUs are useful for appliances that you don't want to keep unplugging - waste disposal units, freezers and fridges, or dishwashers - and have a switch and a neon light indicator to show when the current is flowing.
The size of the cable and the fuse rating depend on the size of the floor area to be supplied by the circuit: in an area of up to 20m sq. (24 sq. yd), the cable must be 2.5mm sq, protected by a 20 amp MCB or 20 amp fuse (which can be of any type). For areas up to 50m sq. m (60 sq. yd) you must use 4mm sq. cable with a 30-amp cartridge fuse or a 32-amp MCB (a re-wireable fuse is not permitted in this instance).
Any number of sockets or FCUs can be supplied from a radial circuit and spurs can be added if required. The circuits are called multi-outlet radial circuits. Powerful appliances such as electric cookers or showers must have their own radial circuit.
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