Cut power to other flats when upgrading mains board.

Discussion in 'Electricians' Talk' started by LSaver, Apr 28, 2022.

  1. LSaver

    LSaver New Member

    Hi All!

    When I replaced my consumer unit, the electrician accidently cut power to all the flats. I have lost contact with him.

    Power is restored but I am wondering how he cut the power and how to fix the issue?

    I think it was the small black boxes in the top left in tamper proof cases. Do you know what these are?

    I will get an electrician to take a look too but I wanted an opinion
     

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  2. Greg64

    Greg64 Member

    If the power is restored there's nothing to fix.
     
  3. Bob256

    Bob256 Active Member

    Is it possible that some whole-building trip was triggered or something?

    I'd be interested to hear what the experts think because I am curious about the arrangement there. My totally amateur take:

    The box on the bottom right (under the black boxes at the top right) is the main fuse, so this is the main supply to the flat (coming from below). I guess the black boxes are some sort of junction blocks, where the incoming supply is then connected to the meter tails, and then from the meter there is the connection to the consumer unit. I am curious about that conduit at the top with the cables that also connect into the junction block. That's the bit I don't understand and wonder if that is related to the issue.
     
  4. Bob Rathbone

    Bob Rathbone Screwfix Select

    Get covers on the bell transformers, it is a shock risk as it stands and would fail an inspection. I do not think you had a real qualified electrician to do the job as he would have picked up on this during his inspection both before and after the consumer unit replacement. Where is the inspection report?
     
  5. MGW

    MGW Screwfix Select

    upload_2022-4-28_9-16-31.png raise questions, are they live? Maybe they are dead, but one would have expected they would have been removed if dead.

    But if he did blow the DNO fuse, the question is why would that affect more than one flat? If the consumer unit feeds multi-flats, how do you decide who pays what for electric?
     
  6. Tony Goddard

    Tony Goddard Screwfix Select

    I'm hoping with MGW those transformers are dead, but if they are they should have been removed, OP have them tested and removed/ replaced as appropriate.

    As to the set up, the main incoming DNO fuse is bottom right, this connects up to a bank of 3 Henley series 1 fuses top right and a neutral link.

    Above that is a pyrotenax cable, presumably running to another flat (flats). Your flat is on the fuse nearest the neutral, the other flats (presumably two) are on the other two, fed via the pyrotenax. All of that is the DNO's property, it's old, but I have a series 1 still supplying my house, they are still out there!

    I'm assuming your electrician pulled the grey main fuse to isolate rather than the fuse just for your flat, hence cut off the lot!! oops!!

    He was a twerp, as that meant he pulled and re-inserted the fuse under load, which is not a good plan!!
     
  7. amendment2

    amendment2 Active Member

    You don't have a problem, the thing with the brown and blue cable in the bottom right hand corner is the dno cutout for the building. The cutout is feeding a 3 gang block of dno fuses and neutral henley block, the fuse on the left feeds your meters. The two other fuse are for other tenants landlords services.
     
  8. Tony Goddard

    Tony Goddard Screwfix Select

    For info/interest only, here is what is behind those brown covers, never remove them, they are not yours and its dangerous to do so untrained.
     

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  9. The Happy Builder

    The Happy Builder Screwfix Select

    Post a picture of your new consumer unit with the cover held open so the main switch, RCDs and MCBs can be seen clearly.

    It all looks very dodgy, I’m just wondering how dodgy it really is.
     
  10. The Happy Builder

    The Happy Builder Screwfix Select

    While you are taking that photo, take another one showing how the earth wire is connected to the incoming electricity supply cable below the main fuse.
     
  11. Tony Goddard

    Tony Goddard Screwfix Select

    There should also be an earth connection to the outer jacket of the pyro, I can see an earth cable and what looks like (hope it isn't) a jubilee clip screw head above the CU to the right end.
     
  12. The Happy Builder

    The Happy Builder Screwfix Select

    The mineral insulated pyro is presumably the “Tails” to the other flats that share the same supply and unsealed DNO fuse in the grey intake at the bottom right.

    The DNO intake fuse holder does not have a main earth conductor coming out of the top of it, so I presume it’s not TN-C-S earthing, there is a small black junction box next to it which may be an earth terminal with a connection to the sheath of the incoming supply cable making it TNS, possibly installed correctly by the DNO with a suitable clamp or possibly just a water pipe earthing clamp or similar.

    Then again it could be TT, but whatever it is I cannot see a suitable earth connection to the outer sheath of the mineral insulated cables to the other flats and they are not terminated into an enclosure.

    The answer to the question why did the other flats is easy, the main fuse was pulled whilst the tails were installed into the new consumer unit.

    The real question is if the installations are earthed correctly and safely, also are those MI cable connections safe, I suspect the answers are no and no.
     
  13. The Happy Builder

    The Happy Builder Screwfix Select

    Looking again, it looks like there’s a water pipe earthing clamp without a label on the MI immediately above the new consumer unit.
     
  14. LSaver

    LSaver New Member

    There is no way that I would be potentially paying the electric for another flat with this set up?
     
  15. Sparkielev

    Sparkielev Screwfix Select

    Tails should have a gland going into DB, no test stickers, looks a bodge
     
  16. Ind spark

    Ind spark Screwfix Select

    You don't need stickers now mate :D
     
  17. MrDC

    MrDC Active Member

    First time I've ever seen a 40A one.

    Out of fascination, what ratings were manufactured and what were commonly used?
     
  18. The Happy Builder

    The Happy Builder Screwfix Select

    I would still be interested to see a picture of what is in the consumer unit, bearing in mind this installation shares a 100 amp fuse with other flats in reality it probably only around a 32 amp supply, if there are secondary fuses on the supply they may well be 40 amp.

    Don't even consider getting an electric car with a charger at home.
     
  19. LSaver

    LSaver New Member

    Hi all!

    Is there a way to try off just my electric but not theirs?

    is there a way to turn off their electric but not mine?


    All the best
     
  20. banger

    banger New Member

    Yes, but you might get severely burnt or killed attempting to do it
     

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