I'm wanting to add another socket outlet to my ring main, on the opposite side of the wall to an existing socket outlet.

When I've removed the old socket the live and neutral wires aren't paired (can't tell which live goes with which neutral).

Does it matter which I pair together? My gut says it does but I'm not 100%.

If it is a problem I guess I'll have to spur the new socket instead.

It's a 1950s house in the UK.

Photo of wires

1 Answer 1


You should not need to select a pair from the four live and neutral wires.

In a ring main the incoming live is always connected to the outgoing live, the incoming neutral is always connected to the outgoing neutral.

To add a second socket on the opposite wall you connect a new cable to all the existing cables - so you get three reds connected, three blacks connected and three greens connected.

With the new colours, a newly purchased piece of twin&earth would have brown for live (connect to both existing reds), blue for neutral (connect to both existing blacks) and bare for ground (cover with green/yellow sleeve and connect to both existing greens). Any connectors you use need to be rated at 32A.

At no point do you separate out one red and one black as a pair. Separating them from the others would split the ring and could cause overheating and fire in one leg of the broken ring.

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Diagram by [email protected] - used under Creative Commons Attribution-Share Alike 2.5 Generic license.

  • So you recommend adding a spur rather than extending the ring? That's what I thought, thank you.
    – Notts90
    Jan 7, 2017 at 12:59
  • 1
    @Notts90: Yes. I see what you were getting at now. But I'd treat it as a spur. That is allowed in the regs and I believe is something a householder can do under Part P without notification etc. Jan 7, 2017 at 13:01

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