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circuit with outside plug keeps tripping

Discussion in 'Electrics UK' started by unclebob1, 15 Mar 2019.

  1. unclebob1

    unclebob1

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    Afternoon all,
    My kitchen ring has over the last week been tripping inconsistantly, sometimes taking the RCD down with it, other times just the mcb for that circuit.

    I suspect that the outside socket which has a fused spur off the ring may be getting wet in this recent wind/water weather event we have had recently.

    The RCD is completely knackered now - it wont reset down, to bring back up so will be replacing that, meanwhile is there any recommendations for 3 pole isolator that i can fit on the spur to disconnect outside all together when not needed? I will be getting outside to check/reseal the outside socket hopefully over the weekend but thought if i can get an isolator then at least i can disconnect from inside the house.
     
  2. JohnW2

    JohnW2

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    Wetness in outdoor electrics would, indeed, be a very common cause of RCD trips, but it is very unlikely that they would cause an MCB to trip - I think you probably need to look for other possible causes.
    It may be knackered, but it could also be that there is an ongoing problem with wetness or suchlike preventing it resetting.
    You only need 2-pole isolation. If the FCU ('fused spur') supplying the outside socket is a switched one, that will almost certainly be a DP switch - and hence would afford 'full isolation'. If it's an unswitched FCU, replace it with a switched one.

    Kind Regards, John
     
  3. unclebob1

    unclebob1

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    Thanks john, the outside socket has a switched fused spur, not sure if its dual pole or single pole, will check tonight.

    The rdc, should it not at least go to off when pushed down? Mine seems not to be even going down - just stays in the middle according to my FIL who called me today with the news.

    Looks like i'll be disconnecting appliances then to see whats causing the problem - list is short though:
    fridge
    freezer
    insinkerator (food waste disposal)
    three transformers for led strips
    cooker igniter
    two pull up socket strips
    coffee machine
    blender


    i'll move the fridge and freezer first to another circuit
    any tips/ideas on which to try next?

    only reason why i suspected outside socket was due to lots of wet and windy weather we have had recently!
     
  4. JohnW2

    JohnW2

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    As I said, I think you'll almost certainly find that it is double pole. I don't think you could buy one today which isn't, and I think that's been true for a long time.
    If you are saying that the RCD will not switch the power off when pushed sown ('firmly', if necessary), then it's certainly knackered and requires replacement. However, since it's upstream of the MCBs, even a seriously knackered RCD could not cause an MCB to trip.
    Yes, since it's MCB trips you are getting, that probably needs to be done.
    Yes, as I said, a very reasonable first assumption in relation to RCD trips, but not MCB ones.

    Kind Regards, John
     
  5. unclebob1

    unclebob1

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    Noted above,

    Some times its just the MCB, others its both MCB and RCD.

    looks like it will be a long night ahead...
     
  6. unclebob1

    unclebob1

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    I've reset the RCD, maybe user error or fault was still present, it didn't reset during the day, but did when I got home. MCB tripped for kitchen ring, so I removed fridge and freezer to different circuit... I've also unplugged two transformers, dishwasher and insinkerator... Now waiting...
     
  7. Taylortwocities

    Taylortwocities

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    When it trips, the operating switch on that type of RCD (is it MK?) moves to the middle position.
    To reset, you need to push the lever down, then push it all the way up.
     
  8. unclebob1

    unclebob1

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    Thanks for the reply taylortwocities.


    They are wylex rcd's either on or off, no middle


    So far moved fridge freezer to another circuit, the other circuit not tripped so not likely to be those two, two of the three led transformers isolated and still tripped.... One isolated and waiting... 6 more items to go...
     
  9. Taylortwocities

    Taylortwocities

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    IMO, if your Wylex RCD trips to the mid position it’s faulty. You need someone with a proper RCD tester to check it out and to change it if needed.

    For once, the fault may be the RCD itself.
     
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  10. JohnW2

    JohnW2

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    I'm still not totally clear as to exactly what the OP is experience - but if a Wylex RCD can't be manually put inbto either the up or down positions, then I would say that one doesn't really need an RCD tester to conclude that it needs replacement. Indeed, if it can't be 'pushed up', I'm not quite sure how one could use a 'proper RCD tester'.
    Yes, it does sound as if that might (as you say 'for once') be part of the problem, but not all of it. Don't forget that what the OPD was primarily suffering was MCB trips - and, as I said before, no matter how faulty/damaged, an upstream RCD could not be the cause of that.

    Kind Regards, John
     
  11. DetlefSchmitz

    DetlefSchmitz

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    I know from bitter experience that something that trips an MCB (such as a short circuit) is capable of destroying an RCD.
     
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  12. JohnW2

    JohnW2

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    Indeed -same here.

    However, as I recently wrote, although it does rather sound as if the RCD has probably been 'destroyed' (by whatever), it still leaves the OP having go find out what was/is causing the multiple MCB trips (and, as your comment suggests, ideally before the RCD is replaced).

    Kind Regards, John
     
  13. DetlefSchmitz

    DetlefSchmitz

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    I don't think I was suggesting otherwise.
     
  14. JohnW2

    JohnW2

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    I'm sure that you weren't. I just wanted to make sure that the OP understood that replacing the RCD before discovering (and remedying) the cause of the MCB trips would probably be unwise - for the reason you mentioned.

    Kind Regards, John
     
  15. conny

    conny

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    If the RCD is knackered, after replacing it and the problem returns simply remove the outdoor circuit from the FCU and monitor the problem.
    If it continues to happen your problem is not the outdoor circuit, (unless the FCU is also outdoors and may be the cause). If it no longer happens the indications point to it being the outdoor circuit.
     
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