plug sockets

[oscarbob]

I am trying to take my electical wiring in my house out of the white coving it has been housed in. I have noticed that there are two wires going into the plug sockets. Can any one please adise me weather this secondary wire is nessacary or if this can be discarded.

 

[viewer]

The second cable is essential. You appear to have a ring final. Both the cables link through the sockets back to the CU so the power is being fed from both "ends". The cable is only big enough to handle the current if both ends and all sockets are connected together.
HTH

 

[viewer]

Hello Oscarbob,
I'm worried that you may have misunderstood the situation. Have a look at the diagram in the Wiki:
//www.diynot.com/wiki/electrics:socket_circuits:a1_ring_final_circuit
This shows how the ring final works. If you have removed a cable and a socket you will have two radials (see //www.diynot.com/wiki/electrics:socket_circuits:b1) fed from the same MCB. This is dangerous as the cable is unlikely to be sufficient and will overheat and not be protected by the MCB because the MCB is sized for the complete ring.This could burn down your house.
Can you post a picture of the cables at the sockets? I'm a little confused as to what you want to achieve in the long-run. Can you please elaborate? I'm going to put this reply on the forum in case others have useful comments.
HTH
V

 

[oscarbob]

Thanks you for this link. I have had a look at the diagram and understand the ring loop now. What i am doing is taking wiring out of coving and putting inside the wall. In the process of doing this i have taken two sockets out. I am left with two loose ends now and i can see that if i connect these together that will complete the loop at the current will run fro both ends from and to the CU. I have now bough something to connect the cable together. Can you please just clarify this is correct, dont want to cause a fire. Thanks again for your help.

 

[ban-all-sheds]

Thanks you for this link. I have had a look at the diagram and understand the ring loop now. What i am doing is taking wiring out of coving and putting inside the wall.

In horizontal or vertical chases? Do you know the maximum depths you should go to with each?

Are you aware of the rules on concealing cables in walls?

• http://www.voltimum.co.uk/files/gb/attachments/niu/l/attachments/c5-43.pdf
• http://web.archive.org/web/20061110111450/http://www.niceic.org.uk/downloads/concealedcables.pdf
• IEE article
• IEE Article on 17th Edition requirements for concealed cables.

In the process of doing this i have taken two sockets out.

Have you allowed for the fact that removing some sockets may remove the zones your cables may run in?

I have now bough something to connect the cable together.

What have you bought?
What is its rating?
If it requires an enclosure did you buy those too?


Are you aware that some types of joint need to remain accessible for inspection & testing?

Regulation 526.3:

Every connection shall be accessible for inspection, testing and maintenance, except for the following:

(i) A joint designed to be buried in the ground
(ii) A compound-filled or encapsulated joint
(iii) A connection between a cold tail and the heating element as in ceiling heating, floor heating or a trace heating system
(iv) A joint made by welding, soldering, brazing or appropriate compression tool
(v) A joint forming part of the equipment complying with the appropriate product standard.

 

[viewer]

All BAS's points are spot on, but you are into the job now, so let's try and make things safe and working. If you could post a picture it would help, but if you can't, then to start, where do the two cables come from (e.g. down wall from ceiling or up from floor)?, how far apart are they? and what have you got to join them.
In principle you're right - joining the cables will re-unite the ring, it's just a matter of avoiding creating any other problems.

 

[oscarbob]

Thank you both again for your help with this. Unfortunately i can get a picture uploaded. I have cut the cable - twin, live earth wire going into the plug socket this then leads out to another plug socket which i have cut out also. There are two loose ends now so i have bought a 13 amp terminal block to connect these together, i am a bit hesitant about doing this now as, even though this seems to complete the circuit looking at bas's comments and links there are only certain connections that can be buried in the wall, is this block one of them? This is all that i have changed to the original layout of the wiring, it is still ok to carry on with this as again following the links i am not changing the layout of the ircuit, just taken two plugs off.

 

[oscarbob]

forgot to mention cables are running from the ceiling, both the loose ends are connected to sockets. The other cables coming off the sockets run back to the CU.

 

[ban-all-sheds]

i am a bit hesitant about doing this now as, even though this seems to complete the circuit looking at bas's comments and links there are only certain connections that can be buried in the wall, is this block one of them?

No it isn't, and 13A is way too small - you need at least a 30A rated connector.

This is all that i have changed to the original layout of the wiring, it is still ok to carry on with this as again following the links i am not changing the layout of the ircuit, just taken two plugs off.

I'm not sure how you've managed to remove two sockets and be able to just join two cables together to complete the circuit, but as for layout, will the cables run in a recognised zone now that those sockets are removed? i.e. were they only OK to be where they were because the sockets were there?

 

[oscarbob]

This is the best digram i could draw to describe the circuit. Not the positioning etc[/img]

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moderator's note:

added

plug layout

• oscarbob
• 16 Feb 2009
• 1

This is how laid out so far. That why i think connecting the cables will be ok.

++++++++++++++++

 

[oscarbob]

What item would i be able to buy in an electric supplier that would be suffix for me to join the cable together and mount that in the valley i am chiselling away at in the wall? Looking at the links you have sent me i have to house the cable in a mettalic housing and this needs to be earthed! What does this mean in idiots term. Is it a metal box? if so were would i get one of these?? As you can probably tell i am trying to do this as cheapily as possible, now i am thinking it might be worth just getting an electrician in to be on the safe side. How much do you think it would cost me for an electrician to lay the cable in the wall for me, and certify his work. If i made the valley and did all the plastering etc.

 

[oscarbob]

forgot to add it is about 15 metres that needs routing.

 

[viewer]

15 metres? That's a long way internally. Is this the distance between the remaining sockets in a straight line (I couldn't open your sketch)? From the earlier posts, I think that you have removed one or two sockets and the cables which connected these to those on either side. The two still connected have cables which drop into them from above and the one(s) you removed are on a horizontal line between these two. Is this correct? If so, do you really want to have fewer sockets? Could you not use a (sunken) backbox and put the sockets in their original situation? This would solve your problem. Whilst it is true that you should be aware of zones, if the original cables were vertical from the sockets or horizontal between two visible sockets there will be no conflict. Does this help?[/b]

 

[ban-all-sheds]

plug layout

• oscarbob
• 16 Feb 2009
• 1

This is how laid out so far. That why i think connecting the cables will be ok.

Oscar - did you not read the documents explaining the concept of cable zones?

You don't show any corners on the diagram, so maybe they are there, but regarding the above as a flat wall you cannot remove the sockets and leave the cables in place as they will no longer be in a zone.

What item would i be able to buy in an electric supplier that would be suffix for me to join the cable together and mount that in the valley i am chiselling away at in the wall?

You'd need to use crimps, as a screwed joint needs to be accessible. There are some proprietary push-fit connector blocks on the market, but the jury is out on whether they comply with the requirements for joints which can be rendered inaccessible....

In terms of a tool for crimping you'll need one of these:

not one of these:

Looking at the links you have sent me i have to house the cable in a mettalic housing and this needs to be earthed! What does this mean in idiots term. Is it a metal box?

If you want to run cables out of zone by using metal conduit then this is the sort of thing you're looking at (pics courtesy of RF Lighting)

if so were would i get one of these??

Any electrical wholesaler will have conduit and bushes etc, as well as the stock & die tools and cutting compound that you'll need to cut threads on the ends. If you need bends in the conduit you'd probably be better off buying them as fittings rather than hiring a bending machine and learning how to use it.

But you face the problem of how will you build a conduit system around installed cabling? You're going to have to chase the walls out anyway, so why not just remove and re-route the cables so that you don't need conduit, junction boxes etc?

Another point to consider is that horizontal chases can't be more than ¹/6 the depth of the wall, and conduit needs deeper ones than just cable.

As you can probably tell i am trying to do this as cheapily as possible,

Fair enough, but "as possible" may not be much like "as I was expecting".

How much do you think it would cost me for an electrician to lay the cable in the wall for me, and certify his work. If i made the valley and did all the plastering etc.

You need to get electricians in to quote.

And if this work is in a kitchen it's notifiable, so another good reason to use an electrician....

 

[oscarbob]

thanks for all this, just to clarify the diagram is just to demonstate the route the cable's are taking and not the way round the living room. When i put the cable in the wall i am noting going to change the route they went i am just going to dig the hole in the wall underneath were the nast white bracket went (not sure the official name for this, think its conjuent) 15 metres is fo the whole hosuse but i am just concentrating on downstairs for now. If it didnt change the route then am i right in saying there is no need for the metal holster. If this is the case then can i just put this stright into the wall in plastic conjuent?