Socket Ring Main Junction Box

These rules apply to spurs also.

Socket ring main junction box.

Step one switch off electricity at the mains you will require two 30amp junction boxes and a length of 2 5mm2 cable the best way of using junction boxes to extend a ring circuit is to find the length of cable between the two sockets on the existing ring closest to the desired extension area. There is no set limit to the number of sockets on a ring main as long as you stay within the rules mentioned above. These rules can be found in our ring main project. A ring main more about ring mains can be found in our project here and also a radial circuit more about radial circuits in our project here will need a 30 amp junction box whereas a lighting circuit although you can buy 5amp junction boxes will need a 20amp junction box.

Locate the cable of the ring main as close to the new socket as possible. Each socket outlet or junction box on the ring can only have one spur connected. Trying to connect two or more is not only very difficult due to the number of wires involved it can also result in an abnormally high load at that point in the ring. Where you desire a socket leave a generous loop of cable out of the wall which can be attached to a new socket once the job has been successfully completed.

Attach the junction box to the plinth making ready for connection. Lift the floorboards and locate the cable that runs closest to your new socket. The diagrammes below show how you can break into a ring main with junction boxes to extend it. The number of spurs on the ring must not exceed the number of other socket outlets.