RCD keeps tripping after replacing cable

Discussion in 'Electricians' Talk' started by Jonny 5, Jan 9, 2019.

  1. Jonny 5

    Jonny 5 New Member

    Hi all,

    I have recently replaced one of the sockets in my house and for some reason it is tripping the RCD on the consumer unit. Can anyone help please?

    A little background info,
    Following some recent works on the house I have had to replace an electrical cable to a socket as the original cable wasn't quite long enough to reach the socket in the new position. Since I have done this, the RCD keeps tripping. I have replaced the cable with the same size and spec.

    I have tried several things to see what is affecting this.
    - I have replaced the socket with a different one to see whether this is at fault (but still trips)
    - put the original cable back in to check if its the new cable (but that trips)
    - bypassing the socket altogether (but still trips)

    The only way the RCD wont trip is if the earths are disconnected from the consumer unit. Even if the circuit breaker is off for this circuit and the earth is then connected then the RCD will trip.

    The socket is on a ring circuit (dedicated solely to sockets), using a twin 2.5mm and earth cable. The circuit breaker for the sockets is B16 but this doesn't trip. The only other connection on this RCD is the kitchen ring circuit that is connected to a B32 circuit breaker.

    Can anyone help please? Before the cable was replaced the circuit worked but since replacing this cable it seems to trip.

    Read more: https://www.diynot.com/diy/threads/cable-replacement-trips-rcd.516018/#ixzz5c92X0KRa
  2. Peterdevon

    Peterdevon Active Member

    You need to test it
  3. Risteard

    Risteard Well-Known Member

    I believe what has happened is that you have ballsed it up.
    Jord86 likes this.
  4. 14th edition

    14th edition Well-Known Member

    Is the neutral connected to the correct side of the CU? If it is you need to get the circuit tested!
  5. Bazza-spark

    Bazza-spark Well-Known Member

    Yes, a qualified electrician can.

    Kind regards
  6. Coloumb

    Coloumb Well-Known Member

    This doesn't make sense. Is the socket you replaced on the 16a breaker or the 32a breaker? It can't be on both. Plus a 16a breaker would more commonly be used on a radial.
  7. Bazza-spark

    Bazza-spark Well-Known Member

    Hi Col

    Happy new year. My reply was in the light he hasn't got a scooby so should get somebody in.

    Best wishes
    Coloumb likes this.
  8. maddawg

    maddawg New Member

    Sounds like it is a radial circuit if there is only one 2.5mm twin and earth cable going to it.Look at this link which might make ring circuits and radials a bit clearer.
    A ring should have each end of the ring going into a 32a breaker in the consumer unit.
    You mentioned your wire goes into a 16a breaker which sounds ok for a radial .
    this it could be a simple fault of the neutral cable insulation being knicked and making contact with the earthed metalwork . have you used rubber grommets on your metal back box ? check to see if the cables are not damaged going into the consumer unit. good luck life is a ***** sometimes when doing something you aren't used to doing .
    rogerk101 likes this.
  9. Bob Rathbone

    Bob Rathbone Well-Known Member

    Got a neutral to earth fault and no idea of how to do the job, sorry but got to be blunt.
  10. spirits are real 2016

    spirits are real 2016 Active Member

    sounds like someone has put a screw in the other part of the ring when the alterations were taking place hitting the earth and neutral and when you put in the new cable it is showing up and they have broken the ring you need to check for continuity on the ring at the consumer unit. live to live and so on and you can check earth to neutral to see if you get a reading.
  11. Bazza-spark

    Bazza-spark Well-Known Member

    Think you need to read #1 again.

    Kind regards
  12. spirits are real 2016

    spirits are real 2016 Active Member

    Jonny said it is on a ring circuit .
  13. Bazza-spark

    Bazza-spark Well-Known Member

    Yes, but maddawg in #9 reckons its a radial on a 16A breaker.

    Read the posts!

    Kind regards

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