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Shed Consumer Unit no power

Discussion in 'Electrics UK' started by Em01, 7 Nov 2020.

  1. Em01

    Em01

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    Two years ago I had a consumer unit fitted in the shed to supply a LED bulk head light and double socket. In the consumer unit I have three switches: one for socket, one for light and the main switch. I wanted to change the light and when wiring it up (with all power off of course) I made a mistake and when I switched the power back on and flicked the light switch some or all switches in the CU tripped (stupidly I did not pay particular attention to which ones or if all of them tripped). I rewired and wanted to test it all again, but now I had no power to the socket or the light (even though I did not change anything in the socket set up). I found that an MCB on the consumer unit in the house had tripped and I reset it hoping that was the solution, but I still had no power. I was then worried that the MCB broke/had blown and I replaced it today, but still no power. What else can I try? Could both circuit breakers in the shed have broken/blown? Is it worth a try changing those?

    Any help/advice would be great! Thanks in advance.
     
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  3. blup

    blup

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    Did the mcb in the house trip again after resetting it and turning on the light switch in the shed?

    Blup
     
  4. Em01

    Em01

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    Thanks for replying!

    No it did not trip again.
     
  5. blup

    blup

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    Maybe the replacement mcb hasn't been fitted correctly on the main CU.

    Blup
     
  6. flameport

    flameport

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    That is so unlikely as to be near impossible.

    What testing equipment have you got - as the first thing is to determine where there is power, or not.
    Randomly swapping items is not a solution to anything.
     
  7. Em01

    Em01

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    This is what I did: it is a Hager MTN132, I opened the screws at top and bottom fully , pulled down the little clip at the back/bottom. Removed the old MCB, pushed the new on on the busbar, pushed little clip at back upwards, tightened bottom screw. Inserted brown wire into top and tightened screw. Does that sound right to you or do you spot a mistake in my description?

    Thanks
     
  8. Em01

    Em01

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    I have got a cheap/amateur multimeter and not a lot of experience using it, but I am always keen to learn new skills. Can you give me some hints? what am I looking for?
     
  9. sparkwright

    sparkwright

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    We could do with photos of inside of the garage cu, the light you wired up, and the cu in the house if it's easy to do.
     
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  11. Em01

    Em01

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    I will go and take some now.
     
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  12. flameport

    flameport

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    You are looking for voltage at each part, starting from the MCB in the house.
     
  13. Em01

    Em01

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    The power to the light goes through a junction box because we had an outside light connected there (and there might be one again in the future if the replacement solar one does not charge enough over the winter.)
     
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  14. Em01

    Em01

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    I guess I would test the cables going into the shed CU to determine if any power arrives there?
     
  15. terryplumb

    terryplumb

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    That would be a start. Check the MCB that you fitted first
     
    Last edited: 7 Nov 2020
  16. Em01

    Em01

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    ok I have just used the multimeter on the consumer unit in the shed. No power is coming into there. I checked the multimeter was working by testing it on a socket outlet in the house. But now what? What could I have done wrong when changing the MCB? What is that little clip at the back for? Everything else seemed pretty straight forward to me.
     
  17. terryplumb

    terryplumb

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    You need to check the MCB at house . Correctly clamped onto the bus bar ,and voltage ok at the top together with the conductor correctly clamped into top terminal.
     
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