Metal Conduit Used As Earth

[bobtol]

Hi
I want to install 2 extra sockets and a sfcu in a hallway. I have opened the socket I was wanting to extend from and have found that there is metal conduit, 2 x red wires and 2 x black wires there is also a red and a black wire looped from one metal conduit pipe to the other. There is also no earth except for the one connecting the socket to the back of the socket back box. Can I add the extra sockets to the ring main from here and add the earth to the back of the box or the back of the socket. The conduit is obviously being used as the earth. I have attached an image of the socket I want to extend from.

What I would like to do is disconnect a set of the red and black supply wires and use wago clips to join them to my new twin and earth so I can then extend the ring main. Once I have added the extra sockets I would then return to the original socket and put the ends where the original ends would go, completing the extension. I would connect the earth from the twin and earth to the back of the socket
Is there any special way I should extend the earth as the conduit is the earth or should connecting it to the back of the socket or back box continue the earth?

Any help is much appreciated.

Untitled

• bobtol
• 26 Mar 2014
• 1

[/b]

 

[Jackrae]

What makes you presume it is a ring main: this could be an extended radial circuit.

The wire is stranded, which was wonderful to work with, so not one of the past few decades installations.

Details (photos) of your consumer unit and it's internals and system earthing arrangements required before any meaningful advice can be given.

There will be those who say rip it all out - but that obviously isn't what you want, or need to hear.

 

[EFLImpudence]

there is also a red and a black wire looped from one metal conduit pipe to the other.

It might be wise to determine what these are.

There is also no earth except for the one connecting the socket to the back of the socket back box.

You need to determine that the conduit is till satisfactorily connected to the socket and is still connected to the Main Earthing Terminal.

Can I add the extra sockets to the ring main from here and add the earth to the back of the box or the back of the socket.

Yes.

The conduit is obviously being used as the earth.

It originally was. We hope it still is.

What I would like to do is disconnect a set of the red and black supply wires and use wago clips to join them to my new twin and earth so I can then extend the ring main. Once I have added the extra sockets I would then return to the original socket and put the ends where the original ends would go, completing the extension. I would connect the earth from the twin and earth to the back of the socket

Yes. Be aware of the prescribed 'safe' zones for cable routing.

Is there any special way I should extend the earth as the conduit is the earth or should connecting it to the back of the socket or back box continue the earth?

Either will do but it is essential that you check the effectiveness of the conduit.

 

[JohnW2]

Can I add the extra sockets to the ring main from here and add the earth to the back of the box or the back of the socket.

Yes.

What I would like to do is disconnect a set of the red and black supply wires and use wago clips to join them to my new twin and earth so I can then extend the ring main. Once I have added the extra sockets I would then return to the original socket and put the ends where the original ends would go, completing the extension. I would connect the earth from the twin and earth to the back of the socket

Yes. Be aware of the prescribed 'safe' zones for cable routing.

... all provided that, as Jackrae said, it can be established that this actually is a ring final circuit.

Kind Regards, John

 

[bobtol]

Hi
Thank you for the quick response

How would you suggest I find out if it is a ring circuit or a radial circuit. would it be the continuity test?

I have seen a socket tester like the one below, would this be the one for testing the earth loop. To see if the conduit is providing a good enough earth.

If after testing the result is the earth is good enough can I then use the twin and earth and connect the earth to the back of the socket or box to extend the earth to my new sockets.

The red and black wires that loop from one pipe to the other, how would I find out what they are, Not really keen on ripping more walls down.
Cheers and thanks again for the quick reply

 

[bobtol]

Hi
I will get some pictures of the consumer unit and get these put up as well.

Thanks again for the help

 

[EFLImpudence]

What makes you presume it is a ring main: this could be an extended radial circuit.

That would still be satisfactory.

Did you mean an extended spur (from a ring)?

 

[bobtol]

Hi
What I meant was, adding 3 sockets 2 x double sockets and 1 sfcu which will operate a set of down lights. from the already existing ring main, If once checked it is a ring main.

If it is a radial circuit can I not then extend from this socket?

 

[EFLImpudence]

If it is a radial circuit can I not then extend from this socket?

Yes, you can. (I think the reference above is a typo).

Only if it is an already non-compliant spur to another spur can you not extend it without a 13A fuse before the first spurred socket.

Obviously anything is possible but that is not likely from the picture.

The extra red and black are a puzzle so anything may have been done.

 

[Jackrae]

An indication of whether it is a radial or ring is by looking at the number of wires coming out of the relevant fuse or MCB. If only 1 wire then it is a radial, if there are 2 it could be either. Not much help but a positive negative !

 

[plugwash]

The extra red and black are a puzzle

Wouldn't seeing an extra red and black go through boxes be quite common with rings in conduit?

 

[EFLImpudence]

How would you suggest I find out if it is a ring circuit or a radial circuit. would it be the continuity test?

Yes, end to end with expected results.

I have seen a socket tester like the one below, would this be the one for testing the earth loop. To see if the conduit is providing a good enough earth.

Nothing below - but yes, it would.

If after testing the result is the earth is good enough can I then use the twin and earth and connect the earth to the back of the socket or box to extend the earth to my new sockets.

Yes, if ring or radial - not spur.
If it is a radial (not likely) you will only require one cable.

The red and black wires that loop from one pipe to the other, how would I find out what they are, Not really keen on ripping more walls down.

That could be difficult unless you can tell where they may go and test for continuity.

 

[EFLImpudence]

The extra red and black are a puzzle

Wouldn't seeing an extra red and black go through boxes be quite common with rings in conduit?

Don't think so. What would be the reason?

Are you thinking there is a socket below?

 

[plugwash]

Don't think so. What would be the reason?

To form the other side of the ring.

 

[dhutch]

To form the other side of the ring.

Would the wring not go in a ring.... if the ring returns via the same route as it goes out, do you not use half as much but slightly thicker cable and call it a radial!

Daniel