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Re-routing a ring mains

Discussion in 'Electrics UK' started by Jupiter01, 8 Jun 2021.

  1. Jupiter01

    Jupiter01

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    I have a break in live and earth on a part of my circuit. I have narrowed this down to a certain part of the ring. I now plan to circumvent this by reducing the ring and cutting out the affected socket. To be honest it's never used anyhow and it avoids me cutting into the wall to make this operational again.

    This will mean that certain cables (L, N &E) are no longer required and will be sitting at the back of the socket (at both ends). What's the best practice for such cables? Should they be terminated using a particular method?

    Thanks in advance.
     
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  3. sparkwright

    sparkwright

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    Are you saying you will disconnect this cable, and leave the ring open??
     
  4. Jupiter01

    Jupiter01

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    I am changing the configuration of the ring to effectively cut out one of the sockets. The ring will be intact but will bypass this socket.

    This leaves me with some cables that aren’t connected at either end but will linger at the back of the socket. How should these be terminated?
     
  5. sparkwright

    sparkwright

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    If you are certain each cable end is completely dead and never to be used again, cut them off as tight as possible.

    Some people say connect all the unused wires to an earth terminal, but all this does is create alarm bells for the next man.
     
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  6. JohnW2

    JohnW2

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    For what it's worth, what I would probably personally do would be to connect all the conductors (including CPC) together in a bit of connector block (or, these days, perhaps Wago) but without connecting them to earth.

    I say that because if I "cut off all the conductors as tight as possible", it probably wouldn't be long before I discovered the folly of my "certainty" that the cable was "never to be used again" :)

    Kind Regards, John
     
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  7. SUNRAY

    SUNRAY

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    Would it not make more sense to fix the fault?
    Unless the cable itself is damaged or a hidden joint has failed it should be in one of the sockets.
     
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  8. Jupiter01

    Jupiter01

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    The issue is not behind the socket. It’s where the cable passes through the wall and ceiling. I never use the socket in question so I thought that reconfiguring the ring may be the easiest option
     
  9. Jupiter01

    Jupiter01

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    connect into a 3 way wago connector or individually terminate each cable into its own wago?
     
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  11. JohnW2

    JohnW2

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    I meant (and would probably do) the former. There would be no harm in doing the latter (provided there were space for the 3 Wagos), but I don't really see any advantage.

    Kind Regards, John
     
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  12. bernardgreen

    bernardgreen

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    Replace "easiest option" with "most dangerous option".
     
  13. blup

    blup

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    What if the cable(s) in question become live again. Isn't it accepted good practice to terminate them in the earth terminal to cover that eventuality? There seem to be different views on the forum over the years from the experts. Or is each approach equally acceptable practice?

    Blup
     
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  14. Jupiter01

    Jupiter01

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    Why do you regard this as a dangerous approach?
    To add, after powering down the circuit, I disconnected all the sockets on this circuit and used my Fluke 2 Pole Tester with a wander lead to test for continuity and establish the route of the ring. This approach also allowed me to establish where the break in Live and Earth is.
     
  15. SUNRAY

    SUNRAY

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    Ahhh so you have identified the faulty cable, and do I assume the other cable going to that socket is ok?

    If that is the case, why not do your bypass as proposed and leave the good cable wired to make the socket a spur on the ring rather than abandoning it?
     
  16. bernardgreen

    bernardgreen

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    Very often the "easy option is not the safest option.

    I may have been a bit too strong in the wording but I had just been involved in sorting out a mess that was caused by a software writer taking an easy option. This easy modification to the motion control module resulted in serious damage to the machine that the software controlled.
     
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  17. JohnW2

    JohnW2

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    I don't think there are (or could be) any regulations which apply to 'bits of cable' which don't currently form part of an electrical installation. Let's face it, if anyone tried to create such a regulation, it would have to be very carefully worded to avoid it applying to the bits (even reels!) of cable lying around in my cellar, workshop and garage :) ... not to mention a lot of VIR cable in many of the walls, under-floor spaces and roof space of my house!

    As you say, views about 'acceptable' (or even 'best') practices vary. I think most of us who have commented have agreed that a reasonable approach is to join all the conductors (including CPC) together (in a bit or connector block, Wago or whatever), so as to make it clear to anyone finding it that it is 'not in use'. As you say, some would also say that the conductors should all be connected to earth. I have no problem with that, but don't generally do it because it might possibly confuse people who found it into thinking that the 'conductors in parallel' were for some reason being used as a CPC.

    Kind Regards, John
     
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