Identify ring circuit legs that are wired in singles

[Ander1975#]

I am adding a socket to an existing ring circuit in a 3 phase cu
All the connections have to be done at the cu as the sockets are inaccessible
I am basically extending the ring circuit
How do I identify the correct ring legs (L,N) (L,N) as they are not taped and the trunkin is packed with cables?

 

[westward10]

How far from the distribution board, not a CU are the new socket outlets.

 

[Eddy Currents]

Connect L+N of 1 leg and L+N of the other leg at the DB and then test resistance between L+N at every point around the ring

If you have connected the 2 separate legs correctly then the resistance at every point should be the same with the exception of spurs which will be slightly higher

If you have connected incorrectly then the resistance will increase at every point until you reach the centre of the ring and then reduce as you move away from the centre back to the DB

 

[westward10]

Connect L+N of 1 leg and L+N of the other leg at the DB and then test resistance between L+N at every point around the ring

If you have connected the 2 separate legs correctly then the resistance at every point should be the same with the exception of spurs which will be slightly higher

If you have connected incorrectly then the resistance will increase at every point until you reach the centre of the ring and then reduce as you move away from the centre back to the DB

How does that help identifying the conductors within the trunking.

 

[Eddy Currents]

How does that help identifying the conductors within the trunking.

OP asked how to identify legs in the DB...

All the connections have to be done at the cu as the sockets are inaccessible

How do I identify the correct ring legs (L,N) (L,N)

And I gave the solution
If OP asked how to identify which leg is which in trunking then I would have suggested using a toner

 

[westward10]

I'm assuming they are trying to find them in the trunking as the post indicates maybe @Ander1975# can clarify.

 

[Ander1975#]

Connect L+N of 1 leg and L+N of the other leg at the DB and then test resistance between L+N at every point around the ring

If you have connected the 2 separate legs correctly then the resistance at every point should be the same with the exception of spurs which will be slightly higher

If you have connected incorrectly then the resistance will increase at every point until you reach the centre of the ring and then reduce as you move away from the centre back to the DB

I was thinking of going to what I think is the first socket in the circuit and disconnecting it,touch both lives to earth then go back to the board and measure each live to earth finding the smallest residence and do the same for the neutrals to find the first leg into the socket
Would this method be ok ?

 

[Ander1975#]

How far from the distribution board, not a CU are the new socket outlets.

I am not sure yet

 

[Eddy Currents]

I was thinking of going to what I think is the first socket in the circuit and disconnecting it,touch both lives to earth then go back to the board and measure each live to earth finding the smallest residence and do the same for the neutrals to find the first leg into the socket
Would this method be ok ?

This might work or not depending on how it was wired as you probably have no idea where the 2nd leg is going and could be going a similar distance to the 1st leg so this method is not reliable which is why rings are tested the way they are (interconnect at db and test at every point)

I suggest doing your ring dead tests before (to confirm which leg is which) and again once work has finished as normal

 

[Pretty Mouth]

1 additional socket. Why extend the ring? Just spur from the MCB

 

[Eddy Currents]

1 additional socket. Why extend the ring? Just spur from the MCB

That's an option if adding just 1 socket but the legs would still have to be identified to correctly test the ring once completed

 

[Ander1975#]

This might work or not depending on how it was wired as you probably have no idea where the 2nd leg is going and could be going a similar distance to the 1st leg so this method is not reliable which is why rings are tested the way they are (interconnect at db and test at every point)

I suggest doing your ring dead tests before (to confirm which leg is which) and again once work has finished as normal

It has been suggested to not add the socket to the ring but to add a spur from the mcb this would mean 3 lives and 3 neural wires at each mcb terminals
Is this ok to do so because it would life alot easier?

 

[Ander1975#]

1 additional socket. Why extend the ring? Just spur from the MCB

Could I do this ?
The ring is wired in 4 mm from a B32 rcbo
I would have to use 4 or 6 mm means 3 wires at each mcb terminal

 

[Pretty Mouth]

Could I do this ?
The ring is wired in 4 mm from a B32 rcbo
I would have to use 4 or 6 mm means 3 wires at each mcb terminal

Appendix 15 of your blue book, and manufacturer's spec will give you terminal capacity

 

[westward10]

What brand is the rcbo. If it is Memshield 2 or Proteus you may struggle with a third line conductor. Just spur from an existing socket.

 

[telectrix]

All the connections have to be done at the cu as the sockets are inaccessible

what'sthe point of having inaccessible sockets?

 

[pc1966]

what'sthe point of having inaccessible sockets?

Kitchen fitters ought to know...