Unable to separate wires on ring circuit

[Andy Gardner]

Hi folks, I'm in the process of adding some more sockets into my "Socket" ring circuit. My plan was to open up the existing socket, cut 1 twin and earth higher up and add a socket there, leave the other twin and earth where it is then do a small ring of 4 sockets, starting at the existing socket and ending at the new socket higher up.
My problem is that having opened up the existing socket, it's actually not twin and earth, it's just the separate cores installed in some metal conduit which goes up into the ceiling! (i.e. 2 live, 2 neutral and 2 earth all in the one metal conduit/pipe)
So, I have 2 questions:
1. Does anyone have any idea how to work out which cables belong to which set?
2. Is it likely to actually cause a problem if I end up having a live from one side and neutral from the other?

Here is a photo of what I mean:

 

[westward10]

Have you just installed that box?

 

[Andy Gardner]

Yes, That is the "new socket higher up" I was referring to. The cable goes through that socket down to the existing socket at the moment.

 

[westward10]

You have some issues here. I assume you have cut that tube away from the old socket back box and hence there may be a possibility it is no longer earthed. Those wires you now have exposed in the wall require suitable enclosure in conduit you cannot leave them as they are.

 

[Andy Gardner]

The original socket didn't actually have any earthing point on it, I would assume that the conduit is already earthed.
Anyway, this setup is only temporary, the idea is that half of the wires will end up in this socket and the other half will continue to run through it down to the existing socket (which is actually a new backbox too). My problem is that I don't know how to split the lives, neutrals and earths.

 

[westward10]

The conduit may well still be earthed or it was earthed by connection to the existing back box. Temporary or not those wires require suitable enclosure. It will be inappropriate to give you advice on how to connect the new socket while you have those wires exposed.

 

[Pete999]

You have some issues here. I assume you have cut that tube away from the old socket back box and hence there may be a possibility it is no longer earthed. Those wires you now have exposed in the wall require suitable enclosure in conduit you cannot leave them as they are.

Andy you need to get an Electrician involved in this project before you do someone a mischief.

 

[Dustydazzler]

This is a very simple job if you know what you are doing...

those cables look awfully tight and also you can't just leave singles in the wall like this , you need a coupler or something to protect the cables

 

[SparkyAndGeorge]

What they mean is possibly the conduit was the earth. It is now not continuous. You need a bush and coupler between the conduit and the backbox. Best advice, get a local sparky in to do this work.

 

[telectrix]

as previous posts. this method of installation is beyond the scope of DIY and/or short course "domestic imbeciles installers". you need an old school sparks to do the job safe.

 

[Charlie_]

The existing circuit might not actually be a ring

 

[Dustydazzler]

The other thing to look at is what the conduit is attached to (if anything) up in the ceiling void.
I have worked in older houses that were rewired in the say 1970s/80s and the conduit has all but been butchered leaving just short lengths down for the drops.
If the conduit going up/down is just flapping in the wind you could potentially replace with pvc tube

 

[Andy Gardner]

Yes, I understand that the conduit may have been the earth. there were no connections from the existing cables the original socket. I sent this photo because this is where I got to and got stuck. I'm not using the sockets like this, the room isn't even in use.
The circuit is indeed a ring.
I was going to simply separate the cables so that one set goes into this socket (which would then be earthed) and the other set goes into the existing socket below (which would also be earthed).
I have metal trunking to go over all exposed cables, to avoid them being drilled into, but I haven't fitted it yet in this area due to it not being finished.

 

[Charlie_]

How do you know that it is indeed a ring?

 

[westward10]

How do you intend to reconnect the conduit to your new back box. The wires from the bottom of the new box need containing in conduit not trunking.

 

[Pete999]

The other thing to look at is what the conduit is attached to (if anything) up in the ceiling void.
I have worked in older houses that were rewired in the say 1970s/80s and the conduit has all but been butchered leaving just short lengths down for the drops.
If the conduit going up/down is just flapping in the wind you could potentially replace with pvc tube

Doubt if that is the case DD, as it's wired in singles. mind you stranger things have happened.

 

[MJPD29]

You definetly need the conduit to meet the back box basic Insulation will not do the job

 

[Andy Gardner]

Ok, well, assuming that I cut off some of the excess conduit so that I can put it in and make sure it touches the backbox, perhaps by welding, what should I do next?

 

[davesparks]

Yes, I understand that the conduit may have been the earth. there were no connections from the existing cables the original socket. I sent this photo because this is where I got to and got stuck. I'm not using the sockets like this, the room isn't even in use.
The circuit is indeed a ring.
I was going to simply separate the cables so that one set goes into this socket (which would then be earthed) and the other set goes into the existing socket below (which would also be earthed).
I have metal trunking to go over all exposed cables, to avoid them being drilled into, but I haven't fitted it yet in this area due to it not being finished.

That conduit needs to be extended so that it connects to the back box. A conduit needs to be installed between the two back boxes for those single core cables to be run through. It must be a proper conduit to enclose the cables, ideally steel, not any sort of capping or partial covering.

What you are currently doing does not comply with the wiring regulations and is creating a potentially dangerous situation which could to you or anyone else in the property being injured or killed at a later date.

 

[Midwest]

How did he cut the conduit and not the singles as well

I’d go with the advice and get someone in, Andy.

 

[westward10]

Ok, well, assuming that I cut off some of the excess conduit so that I can put it in and make sure it touches the backbox, perhaps by welding, what should I do next?

What you should do next is use the services of an electrician one who is skilled enough to reinstate the conduit.

 

[Andy Gardner]

Ok, but I don't understand how the conduit is the earth as well as having the 2 earth cables inside the conduit?

How did he cut the conduit and not the singles as well

My dad used a pipe cutter and a hacksaw, carefully!

 

[westward10]

The conduit is not the earth for the circuit but it still needs to be earthed.

 

[westward10]

Ok, but I don't understand how the conduit is the earth as well as having the 2 earth cables inside the conduit?

My dad used a pipe cutter and a hacksaw, carefully!

That is where all your problems started cutting that conduit off, bad move.

 

[Andy Gardner]

Ok, but I am absolutely certain that there were no cables joining the existing backbox to the earth of the circuit, so what is the difference between not having anything joined to socket and not having anything joined to the conduit on it's own?

 

[westward10]

The back box and conduit are earthed by way of connection and the socket outlet fixing screws.
You need an electrician to sort your predicament.

 

[Pete999]

The back box and conduit are earthed by way of connection and the socket outlet fixing screws.
You need an electrician to sort your predicament.

The back box and conduit are earthed by way of connection and the socket outlet fixing screws.
You need an electrician to sort your predicament.

 

[Barnaby Stedman]

Alternatively you could disconnect the conduit at the last connection point and run the correct length conduit if you had any spare metal conduit around.

 

[Barnaby Stedman]

But it's crucial that you understand how you can connect the back box and the conduit.

 

[Pete999]

Assuming the OP knows how to reconnect the conduit to the correct standard, the original question about how to find the correct three single cables needed to connect up the RFC, begs to ask the question, does he have the knowledge to test and ensure the RFC is actually an RFC and not a Radial.
Who will be testing and certifying the install? I'll stand by my original advice and tell him to get a Spark in to do the work for him, offering advice could prove to be a dangerous activity.

 

[buzzlightyear]

looking through me eyes its like a hammer cracking a snail .nice job by the way ,not .

 

[Midwest]

Whats the set up of your fuseboard OP?

 

[mattg4321]

4 inch nail

 

[davesparks]

Ok, but I am absolutely certain that there were no cables joining the existing backbox to the earth of the circuit, so what is the difference between not having anything joined to socket and not having anything joined to the conduit on it's own?

There would have been the two screws holding the socket onto the back box for a start.
The difference is that you are carrying out this work now and must comply with current regulations.

 

[davesparks]

Ok, but I don't understand how the conduit is the earth as well as having the 2 earth cables inside the conduit?

My dad used a pipe cutter and a hacksaw, carefully!

Well now you need to get the conduit out of the wall to cut a thread on the end of it to join a new piece of conduit to it. But it is likely to be imperial conduit so you'll probably need to replace that piece of conduit using an imperial to metric adapter wherever it starts from

 

[buzzlightyear]

But it is likely to be imperial conduit so you'll probably need to replace that piece of conduit using an imperial to metric adapter wherever it starts from

and a wielder.or one

of those .

 

[Andy Gardner]

There would have been the two screws holding the socket onto the back box for a start.

Actually, when I started taking this apart, there was no socket on the original backbox, it had just had some twin and earth run directly from that backbox at a diagonal angle directly in the plaster with nothing covering it, then they plastered straight over the backbox, no faceplate or anything, just some gaffa tape covering the cables! So it certainly hadn't had any earth in it for a long time. (that was not my doing, for the record)

Well now you need to get the conduit out of the wall to cut a thread on the end of it to join a new piece of conduit to it.

Yes, I worked out that I can actually use the coupler and bush from the old backbox, I just need to somehow thread the existing conduit on the wall...

I have now actually traced the wires back to the fusebox, by turning off the power completely, removing 1 wire at a time from both the socket circuit MCB and the 1 existing socket, thus now knowing which wires go where. Now just got to get the conduit sorted!

Don't worry, I'm not actually going to do the wiring until the conduit is sorted, and yes, I am going to get someone to sign off on the installation once it's done.

 

[Taylortwocities]

@Andy Gardner I'm curious. How did you actually achieve this. You have a new back box inserted into the middle of a conduit run. You have said that your father has cut the conduit with a pipe cutter and pipe slice. (I'm impressed he did that with the singles still in place without damaging the conductors.

Having done the cuts, how did you remove the piece of conduit and get the singles through the holes in the back box?
Is there another box above or below the new box that you have access to?

 

[Lucien Nunes]

If it's 20mm, how about a Conlok coupler to connect the existing run to a barrel nipple, coupler and bush to get into the new box. Are Conlok joints designed to be buried in plaster? OTOH if this is 3/4", which presumably 20mm Conlok isn't designed to grip, and you won't readily be able to thread, cutting off the bottom threaded end has left you a bit stuck.

 

[Kojak]

Those wires look old, I would say just replace the whole circuit to current standards. Whoever you're getting to test it, have him in first to advise you on how to do it. Take pictures as you go so he can see you've done it right.