A radial circuit describes the circuit that is commonly used to distribute power to sockets and lights around the home and in which the last point or connection in the series is not required to link back into the source of the power. This means that the circuit does not have to distribute the power in a loop and can create a straight line of distribution, particularly useful in a situation where it would be impractical to route the wire from the last light or socket in the series back to the originating power source. This contrasts with ring main circuits, which must have a point of return back into the power supply.
In a radial circuit of power sockets, the area must not exceed 50sqms, but additional spurs or sockets may be added to the circuit. The number of additional sockets must not exceed the original number of sockets. For example, if there were five sockets on the original circuit, then you can only add a further five. This type of cabling arrangement is primarily used to feed electricity to standard lights, switches and power sockets. Any circuit that requires additional electrical loading, such as the power supply to an electric cooker and for some types of heating, will likely require their own individual circuits and it is not recommended that you add anything, whether they be lights, switches or sockets, to those kinds of circuits without proper advice from a fully qualified electrician.