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Borrowed neutrals

Discussion in 'Electrics UK' started by SUNRAY, 12 Mar 2021.

  1. SUNRAY

    SUNRAY

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    Sadly my phone is complaining of no memory so unable to take pics today.

    I've been out assisting another to find out why the New CU fitted in a rental property [by sparks sent in by agent] "Doesn't work".

    For a start we found the customer with no working power apart from shower and the CU has not been changed but a couple of RCD's have been added to the 30yo plastic Hagar to feed 4&5 circuits each.

    total of 11 red wires from 3/0.029" & 1mm² to 10mm² however neutral blacks consist of 1x 10mm² [shower T&E], 1x 1mm² [outside light T&E] & 2x [estimated] 7/0.044" arranged as ring with lots of original junction boxes I'd describe as an oversized Besa about 3½-4" diameter containing a single brass block with 9 screws, a bit like these:
    [​IMG]
    but 3 holes each side which don't go right through, 2 screws one side and one the other side.

    I have no idea what the heck was going through the mind of the person tasked to do the EICR and changes, but he'd simply put each end of the neutral ring into an RCD along with another neutral wire, something like this.
    upload_2021-3-12_18-3-0.png
    And of course installations of this age relied on the split tube for earth.
     
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  3. ericmark

    ericmark

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    Hope he does not get paid. But it is not the first or I am sure the last where some one who clearly was not really an electrician has tried and failed to fit RCD protection.

    OK in my case it was around 2006 and early days of 30 mA RCD's in domestic, however the "electrician" had no test gear other than a multi-meter, and was employed to put a supply in for a shower and underfloor heating by the builders, and we got a phone call offering for £100 extra he would swap whole consumer unit rather than henley block and mini one. That seemed very cheap so yes go for it.

    When I returned the guy was pulling his hair out as he could not get one RCD to hold in, so he swapped for an isolator with promise to return next day. Never to be seen again. Also the builder folded so to be fair likely he was only paid by us the extra £100. And of course no paperwork, so not a clue who he was, except Cornwen area of North Wales.

    House was rewired some 10 years latter.

    But to me the errors is not really the issue here, what is the issue is leaving a home without power. At least the guy doing my mothers house left all working, even if no RCD protection, I can understand missing a two way light circuit which only trips with one combination and the electrician did not pick up on the fault, this happened in my house when new consumer unit fitted, one four gang light switch had two neutrals and wrong one used for one light. But to walk away from a domestic installation leaving no power he needs to be named and shamed.

    OK his workmanship may not be up to standard, but leaving a house hold without power is unacceptable.
     
  4. SUNRAY

    SUNRAY

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    I give him his dues he didn't 'walk away with no power', he told the agent there were problems and it needed further investigation so they called us in, the customer was not at home at the time and not expected until evening so knew only that the electrician would be in attendance in their absence.

    The number of times I've come across mixed up lighting circuits is unreal and thats not only shared neutrals. The popular method of converting 2 single switched lights into 2 way drives me mad but at least the symptoms are known. There was one posted on here a while back over 4 floors which was also mixed with the shower circuit [builders botching]. I felt really sorry for the guy trying to sort it out as the builders had been arrested.

    Even now the price difference between adding a small CU and changing to a bigger is not a lot different to the £100, if the devices can be re-used it may even work out cheaper. We did exactly that not that long ago with an almost new metal 4+4 Schneider for a hot tub and provision for future shed supply, the space for a second board was not there and the current tails would have been awkward for Henley as they ran behind the backboard and straight into the back of the CU, the larger CU easily fitted in the space without re-routing tails. The price difference between bigger CU with isolator & 2x RCD or a 4 way plus henley, stuffing gland and tails was not £100, the additional time taken to replace the CU over adding a 2nd CU in a difficult situation was minimal [possibly even quicker] so in that instance it made total sense to change it.
    Initially the customer was not impressed with the idea of replacing his virtually new CU, however he soon liked the idea of using it in his shed when built.
     
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  5. DIYnot Local

    DIYnot Local

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