extending ring main

[reidsimon]

i have looked at all the other posts but i donot think any answer my question

i have a single socket in dining room fed by two cables running from upstairs in the wall. I assume this is a ring main. I would like to extend that ring main to feed a further 3 plugs in that room, My question is, do i connect that cable back into that socket once i have added the other sockets. This will result in there being 5 cables going to that single socket which sounds impossible ( includes one spur going to one other socket in another room)

 

[OwainDIYer]

No.

Firstly you must establish whether the socket is on the ring circuit and is not spurred; you cannot assume that it is as it was permitted under previous regulations to have two single sockets on a spur (so the 'middle' socket would have two cables) and you cannot spur any further.

You cannot spur 3 sockets off a socket on the ring; apart from not getting the wires into the terminals this could create a high point loading and unbalance the ring.

IF the socket IS on the ring then you extend the ring, making a new loop connecting the new sockets, and each end of the new loop connects to the existing ring. One end of the new loop and one end of the ring will connect using the existing socket terminals; the other end of the new loop and the other end of the ring will be connected using terminal strip behind the socket.

 

[PrenticeBoyofDerry]

Firstly you need to confirm whether it is a ring final circuit or not. Most socket will have two sets of cables terminated to them. This does not give any clues to the type of circuit it is, it could still be either a ring or a radial circuit. Further investigation and electrical testing would be the best method to confirm the type of circuit. Even looking at the fuse board/CU at the fuse rating and cable numbers does not confirm the type of circuit it is.

As above don't rule out spurs from spurs either.

To extend a ring final circuit, you need to extend by connecting to both incoming and outgoing legs. This is possible within a backbox, but not by connecting all conductors to the socket terminals, you can break into one of the legs and extend using connectors in the back box and returning back to the socket terminals with the second leg of the extension. You could but new lengths of cables in to extend neatly, or you could break into the circuit within floor/ceiling void and extend there, this would require two joints (in/out). Requirements would mean that maintenance free joints would very likely be required to do this.
Other consideration would be 13A fuse connection of the ring final, from there you can have a number of socket outlets but restricted to 13A on full load.
Radial circuit allow for spurs from spurs

Also follow permitted safe routes of new cables and note the requirements for RCD protection on buried cable and new socket outlets

 

[Taylortwocities]

Like many, many questions there is detail on how to do this in the WIKI at
//www.diynot.com/wiki/Electrics:Extend_Ring