Extending ring circuit

[AnonymousImport]

I am extending the ring circuit in my house by running two pairs of wires from an existing socket. To do this, I plan to terminate one of the two new pairs, and one of the existing pairs, on the existing plug socket terminals. For the other pair of (one new and one old) cables, I was thinking of tying them together (using separate terminals/connectors) within the mounting box for the socket. It all seems fine in theory, but is this actually a dumb/dangerous thing to do? I am wondering whether "cramming" the mounting box like this is likely to lead to problems with heat for example.

I want to avoid using a spur as I plan to add an additional 3 points and I believe that you shouldn't add more than one socket on a spur. The option of taking the other "end" of the ring circuit from the next socket on the ring is also out for me because of the current state of the house (would require exploring walls, pulling up floorboards, etc., which is a lot of work that I'd much rather avoid).

Any advice would be greatly appreciated.

Thanks.

 

[AnonymousImport]

if i understand you correctly, do not even think about it.
As you said it is a ring circuit, (you are also right about the one spur off one socket) the cables must be in a continious ring (almost what you had in mind, but you can connect them via a 30 amp junction box and put this under the floor. It must also be a 30 amp junction box, not 5amp or 10 BUT 30, also the new cables you are proposing to install should be the SAME size of the existing cables (usually 2.5 mm twin & earth)

 

[AnonymousImport]

You CAN do it in the back box if you joint the cables with yellow through crimps using a calibrated crimper. Don't use connector blocks. Don't use crimps unless heat shrink sleeved, in a box, conduit or trunking.

If the junction box under the floor or crimps don't suit, you could put an additional socket(s) / fused spur below or next to the existing (in fact anywhere as long as the cable you need to joint will reach and you can make it look presentable) -use it to joint your cables. Solved the joint problem and gained extra sockets. Bonus!

 

[AnonymousImport]

Thanks for the reply. My biggest problem is the route for the additional ring cables to take, for them to reach the new points. The most convenient route is the space behind the wall where an existing socket is sited - I can run both "ends" of the (new) ring cable through that space if I feed off that socket. My main concern was that by extending one of the existing ring cables by connecting it directly to one end of the new portion of ring, I'd be introducing a risk of overheating, or worse, in the socket mounting where these two cables would be tied. Is this the risk here, or is this idea even more crazy than that?

From what you wrote I take it that it would be better to tap into the ring at some mid point, add a 30amp junction box, and wire out from that to the new portion of the ring? The difficulty that I face with this is getting access to the cable at some point other than an existing socket. However, if that is the only safe way to do it then I might just have to dig out the handsaw and crowbar...

 

[AnonymousImport]

Crimping sounds like the way to go for me. Are crimping tools specialised pieces of kit i.e. are they expensive and are they usable by the average member of the public?

 

[AnonymousImport]

crimping tools are readily available from any electrical wholesaler, DO NOT use the ones you find in a DIY super store, they work, but are not reliable enough.
Also i would point out that although crimps are good, a decent pair of crimpers (with ratchet action)may be about £30 or more (cant remeber how much mine were), although money is nothing compared to a life, i would suggest that a 30 amp junction box is easier and cheaper, and in some circles safer, since each wire has a direct contact as opposed to a crimper which relies on the material of the crimp.
Also crimps take practice to get right first time, even then sometimes when pulled (to see if it comes off) i still find it is wrong.

If you do go for a junction box make sure you use the correct size screw driver for the screws, and make sure they are tight, fires are caused by poor joints that are loose, the current then arcs across causing heat then fire.