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Wylex NSB20 Single Pole MCB tripping

Discussion in 'Electrics UK' started by BillGreenwood, 21 Jan 2021.

  1. BillGreenwood

    BillGreenwood

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    Hi

    My daughter has an issue with her electrics and I'm wondering if anyone can throw some ideas out here. The issue is with a local authority flat and in these Covid times getting the Council to come out and check anything takes weeks!

    She has an issue where she will wake up the flat sockets are off. Except for kitchen (sockets), which is on its own circuit. Once they woke up, switched off and unplugged from a socket a 12" bedside fan and this tripped the MCB. The fan hasn't been used since and there are still issues.

    Admittedly she does have a few extension leads (but all are brand quality and surge-protected) and into these are things like phone chargers/ipad charger). Her son has a PC/monitor/Playstation/Phone charger in another 4-way socket. Nothing causing a major power drain.

    When this happens, she removes ALL the plugs in the house from the sockets, to be sure nothing is available to trip again. The MCB takes hours / sometimes over a day to be able to switch on. Then a few weeks later again the MCB goes off. Could the MCB be old and faulty? Is there a test to see if the MCB is faulty?

    As will be seen from the image, the shower, cooker, immersion heater and sockets are protected by an RCD which does not trip itself. It there too much load on this section?

    The CU was tested and passed last year, so I'm guessing all must be ok with the installation. Any ideas please? Thanks.

    WhatsApp Image 2021-01-21 at 15.16.48.jpeg WhatsApp Image 2021-01-21 at 15.28.13.jpeg
     
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  3. terryplumb

    terryplumb

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    The MCB looks dodgy ,in its tripped position it looks askew!!
     
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  4. AndyPRK

    AndyPRK

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    It's a wylex plastic board. They all look askew!! :D

    The flag in the RCD looks dodgy. But best not to touch it in these times
     
  5. terryplumb

    terryplumb

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    I wasn't referring to its position being truly vertical Andy ,just look at the horizontal of the black switch .
     
  6. flameport

    flameport

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    There is a serious fault in the wiring, the consumer unit or both.
    You cannot fix this yourself.
    Call the property owner / council or whoever is responsible for it.
    Until they get there and repair it, leave it switched off.
     
  7. BillGreenwood

    BillGreenwood

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    Hi flameport.

    There was an inspection in November 2020.

    My daughter has contacted the council, but they won't come out at the moment due to Covid they say. The Council say, as she has power in the kitchen, it's not a grade 1 emergency. So we wait till the MCB will switch on.

    I'm just wondering how is it, that the MCB takes so many hours (sometimes over a day) to reset. A cooling issue on the MCB? I don't want to speculate much myself not will anyone fix it ourselves. We will leave this to the experts.

    Cheers



    WhatsApp Image 2021-01-21 at 15.28.31.jpeg
     
  8. BillGreenwood

    BillGreenwood

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    Hey AndyPRK.

    Can you explain more about the RCD flag please? I will do some googling myself.

    I'd like to put a case (email) to the housing so they come out and fix it. My email will just go to some housing manager and if I cant put a valid case to get someone out to take a look then the electrically untrained housing manager will just spike the request!

    Cheers

    Bill
     
  9. chivers67

    chivers67

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    There should be a set of FULL Test results somewhere - you could contact Evans & Shea to see what they were as they'd have recorded them on software (one would hope). Is there any damp in the flat anywhere? Like somewhere the clothes are put on to dry?

    IMHO The RCD needs to be Ramp Tested as it may well be that it is faulty, especially given Andy has noticed the Flag window. You could turn all the circuits off Fed from the RCD and reset it and press the Test button to see if the Window shows full Red and Full Green when that's done
     
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  11. terryplumb

    terryplumb

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    It's the MCB that trips ,the RCD doesn't.
     
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  12. chivers67

    chivers67

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    So something is overloading it but a bit of a puzzle as it won't reset. Really needs the circuit to be thoroughly Tested, taken apart and end to end resistance measured and Insulation Resistance too. Might be a high resistance short somewhere that's stopping it from being Reset. I'm tending to agree with Flameport

    That sheet isn't from 2020 EICR is it? The Silver RCD label should have been updated - not that it's highly critical.

    [​IMG]
     
  13. BillGreenwood

    BillGreenwood

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    Tbh. I don't know when the yellow note was placed. The flat is my daughters and I've never looked at the board before. I did some C&G electrics 35 years ago (and passed) but never went into the trade, so I've an understanding but I'm far from an expert.

    In hoping I can take some ideas from you guys and flumox the housing team and force them to get someone out. I'm.not concerned about the flat exploding. It's just a big hassle for my daughter.

    Thanks for all your help everyone.

    Bill
     
  14. flameport

    flameport

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    Either there is a damaged cable somewhere causing a short circuit, and eventually the huge current the flows when attempting to reset it blows the fault clear for a short time
    or the MCB itself is damaged internally, most likely due to overheating.

    Either way, it is not suitable to continue using, doing to is risking a serious fire.
    That consumer unit is also of the type which was subject to a recall a number of years ago as the large numbers of those circuit breakers were faulty and caused several fires.

    That changes nothing. Things can break and fail at any time.

    The RCD should show red when on, green when off.
    Yours shows both, which means something internally has failed/gone out of alignment/broken. It needs to be replaced.

    To trip a 20A circuit breaker takes 30+ amps. That's over 7kW of heating load, the equivalent of a 4 ring electric hob being on full.
    That heat is going somwhere - into the building, the consumer unit or both.

    You need to switch that circuit off, and not use it until it is properly repaired.
    Continuing to use it is risking a fire.
     
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  15. BillGreenwood

    BillGreenwood

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    The shower room backs onto this Consumer unit and the immersion / boiler is next to it too. I doubt the CU will be moved. There are 32 flats in the block and we're told everyone has the same board/setup and we are the only one with issues, so it must be a the family causing the issue. :/
     
  16. BillGreenwood

    BillGreenwood

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    Noted! And thank you. I'll make sure it's off!
     
  17. EFLImpudence

    EFLImpudence

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    I would agree that the MCB looks broken - so anything could be happening inside to prevent resetting.

    What does it feel like compared with one of the others?
     
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