new socket under existing socket

[justintime2]

Hi

I currently have an existing double socket at eye level, intended for a wall mount TV. Since this will be inaccessible once a TV is mounted in front of it, I'd like to add a double socket underneath at the more usual height eg closer to knee height.

I found the following example here on the site but wanted to check a couple of things please.

//www.diynot.com/wiki/electrics:extend_ring

The example shows one cable being removed from the pattress and running horizontally outside of the horizontal zone and the same for the return cable.

With the new socket I wish to add would it be correct to have one of the existing cables simply passing through the new pattress for the lower socket onwards to the existing socket above?

The existing cables run up the wall from the floor.

Would it be correct to then shorten one cable feeding up into the lower socket and then add a new length of 2.5 t&e to return from the highest socket to the lower one?

The example above states to remove the right hand cable but is that to be regs compliant or just that the example is dealing with some new sockets to the right of the existing one?

Kind regards
Justin

 

[JohnW2]

I currently have an existing double socket at eye level, intended for a wall mount TV. Since this will be inaccessible once a TV is mounted in front of it, I'd like to add a double socket underneath at the more usual height eg closer to knee height.

What you go on to say seems to assume that the existing socket is part of a ring circuit. However, are you sure that is the case - rather, than, say, it being a 'spur' (with just a single cable) taken from a ring circuit? The answer to that could affect what you are allowed (or not allowed) to do in terms of adding an additional socket.

Kind Regards, John

 

[justintime2]

Hi John

Sorry for confusion.

The existing socket has two cables and I've not discovered any sockets in the house which have only a single cable unless they relate to a single spur that I've added. Therefore to the best of my knowledge I believe I have a ring circuit. The house is only aprox. 5 year old Wimpey if that helps.

Kind regards
Justin

 

[JohnW2]

Hi John ... Sorry for confusion. ... The existing socket has two cables and I've not discovered any sockets in the house which have only a single cable unless they relate to a single spur that I've added. Therefore to the best of my knowledge I believe I have a ring circuit.

The existence of two cables unfortunately does not conclusively prove that it's part of a ring - it could, for example, be a spur from a ring with a further (non-compliant!) spur already taken from it. An electrician would be able to determine for sure what was going on.

Kind Regards, John

 

[justintime2]

Hi John,

I think it's unlikely to be non compliant since the cables were buried in parts under dot and dab so I think they are most likely part of the original wiring of the house.

Kind regards
Justin

 

[JohnW2]

Hi John, I think it's unlikely to be non compliant since the cables were buried in parts under dot and dab so I think they are most likely part of the original wiring of the house.

You are very probably right. All I can tell you is that, without testing, you cannot be absolutely certain that the socket is part of a ring - it's then up to you Returning to your original question:

With the new socket I wish to add would it be correct to have one of the existing cables simply passing through the new pattress for the lower socket onwards to the existing socket above? ... The existing cables run up the wall from the floor. ... Would it be correct to then shorten one cable feeding up into the lower socket and then add a new length of 2.5 t&e to return from the highest socket to the lower one?

IF the existing socket is part of a ring then, yes, what you describe would be an appropriate procedure.

Kind Regards, John

 

[OwainDIYer]

I think it's unlikely to be non compliant since the cables were buried in parts under dot and dab so I think they are most likely part of the original wiring of the house.

That's optimistic

Also until I think 14th edition it was permissible to run 2 single sockets on a spur, so the socket in the middle would have two cables to it.

 

[deadshort]

Hi, as you have said the house is 5 years old,and you have 2 cables to the socket above and you are pulling one back and adding a bit of 2.5mm from your new socket to your existing on behind your TV is exactly what an electrician would do.

Kind regards,

DS

 

[JohnW2]

Hi, as you have said the house is 5 years old,and you have 2 cables to the socket above and you are pulling one back and adding a bit of 2.5mm from your new socket to your existing on behind your TV is exactly what an electrician would do.

It is indeed, but if it were a decent electrician, only after undertaking a couple of simple tests to confirm the (I agree, almost certainly true) fact that it was, indeed, on a ring.

Those who 'assume', even when the assumption is a 'very probably valid' one, eventually discover why they shouldn't

Kind Regards, John

 

[JohnW2]

Duplicate deleted.

 

[phatboy]

I suppose a valid test for a non-electrician would be to disconnect the existing socket, and insulate each core of each cable separately, re-energise the circuit and see if any other sockets on the circuit stopped functioning?

However, the OP doesn't mention if they have owned the house from new (unless I missed it), but if they have, it would be a even more safe bet that the socket was part of a ring I think.

 

[JohnW2]

I suppose a valid test for a non-electrician would be to disconnect the existing socket, and insulate each core of each cable separately, re-energise the circuit and see if any other sockets on the circuit stopped functioning?

If that's all one did, none of the sockets (other than the one which had been disconnected) would stop working, since each one would get power via one arm of the ring or the other - is that what you meant?

However, the OP doesn't mention if they have owned the house from new (unless I missed it), but if they have, it would be a even more safe bet that the socket was part of a ring I think.

I agree that it's very probable that the socket is on a ring, and that many might be happy to gamble on that being the case. However, if any of the sockets in a new build were spurred off rings, one high up on a wall might be somewhat of a suspect. For the sake of the five minutes it would probably take me to satisfy myself that it was on a ring, I'd personally probably check- but opinions will undoubtedly vary!

Kind Regards, John

 

[phatboy]

I suppose a valid test for a non-electrician would be to disconnect the existing socket, and insulate each core of each cable separately, re-energise the circuit and see if any other sockets on the circuit stopped functioning?

If that's all one did, none of the sockets (other than the one which had been disconnected) would stop working, since each one would get power via one arm of the ring or the other - is that what you meant?

If you got power from 1 arm or the other of the ring, then it would prove the socket was part of the ring yes. However if a socket, or sockets lost power, it would prove it/they was a spur. Is my logic sound here?

 

[JohnW2]

I suppose a valid test for a non-electrician would be to disconnect the existing socket, and insulate each core of each cable separately, re-energise the circuit and see if any other sockets on the circuit stopped functioning?

If that's all one did, none of the sockets (other than the one which had been disconnected) would stop working, since each one would get power via one arm of the ring or the other - is that what you meant?

If you got power from 1 arm or the other of the ring, then it would prove the socket was part of the ring yes. However if a socket, or sockets lost power, it would prove it/they was a spur. Is my logic sound here?

Not totally, unless one is somehow certain that the socket is either part of a ring final or a spur from a ring final. If it were part of a radial circuit, then all sockets downstream of the one you'd disconnected would become dead (yet it would be OK to branch/'spur' from the socket of interest to a new one).

Kind Regards, John

 

[justintime2]

Hi All,

Thanks to all for the input.

What I've done this morning to investigate further is to use a hole saw to drill a couple of holes in the floor. From this I've been able to establish that one of the legs from the TV socket continues under the floor to the next nearest socket on the adjacent wall to the left. This next socket only has 2 legs of cable in it as do the rest of the sockets on this floor.

Kind regards
Justin