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Wiring a consumer unit to the mains

Discussion in 'Electrics UK' started by neljan, 2 Jun 2014.

  1. neljan

    neljan

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    Hello

    I recently moved home and found that the previous owner (an electrician) had installed some power sockets in the loft, however the sockets have no power. The sockets are connected to a 2-way Distribution Board with MCBs, which has the main feeder cable for the board hanging out of the bottom of it. There is also a seperate working plug socket in the loft, which is connected to the main consumer unit downstairs.

    So... I was wondering (pretty sure I know the answer though!) would it be possible to connect the Distribution Board's main feeder cable to the existing working sockets supply via a junction box? If not, then could someone please advise me on where I should connect the main feeder cable to?

    Thank you kindly.
     
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  3. neljan

    neljan

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    Forgot to mention that there are 5 double sockets so they'd require 100 amps in total (if my Googling skills are correct?). Cheers
     
  4. EFLImpudence

    EFLImpudence

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    Is this still just a loft or a loft conversion?


    A double socket is rated for a maximum of 20A but that doesn't mean the supply has to be 20 x no.of sockets.
    60A supply is all a lot of whole properties have.
     
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  5. neljan

    neljan

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    It's a loft conversion.

    Thanks for the info. I'm just curious as to why he never finished connecting the unit to the existing loft supply having gone to all the trouble to install the sockets/wiring etc. There's only a single double plug socket in the loft connected to the main unit downstairs, so even if I disconnected that and used that cable to feed this new distribution unit it should be fine?

    *edit* ah perhaps he was intending to use the existing connection as a light (there is no light there) and run a new feed from the main unit for the sockets, unless it's possible to have power and light from one feed?
     
  6. EFLImpudence

    EFLImpudence

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    You don't really need another DB in the loft but there may be a good reason for fitting it.
    Is there an RCD in it?


    What rating of MCB is in the main house DB covering the single socket that is powered and is there an RCD protecting it??
    Do you know what size (cross-sectional area) the cable is?
     
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  7. EFLImpudence

    EFLImpudence

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    Can you post some pictures of the relevant parts?
     
  8. neljan

    neljan

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    No. There's a Wyflex B10 and a B20, then there's a Wyflex WS602.

    The MCB is a Proteus 616/2 16A type 2 M6.
    No RCD.

    The redundant DB's cable is 176 A
    The powered cable is a standard plug lead size (38 A)

     
  9. ericmark

    ericmark

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    I always worry where I have to take over a job. What is actually where you can't see. Years ago I rang out a cable and it went where I wanted so I used it only to find out there was a branch which I was unaware of and this resulted in bare live wires. I was lucky no one hurt but it taught me a lesson.

    Again early in my days as an electrician I would leave a cable just in case I needed it latter now I realise no one with any sense used cables they have not fitted. So now I rip out any cable not used.

    In some cases with surface cables you can fully inspect and test but one can't assume anything you have to test all cables unless you find something which shows already tested.
     
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  11. Murdochcat

    Murdochcat

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    I'm lost - 176A & 38A

    Are you sure you are competent to do this work?
     
  12. sparkwright

    sparkwright

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    Can you explain this bit?
     
  13. neljan

    neljan

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    Yeah sorry, I've never heard of "cross-sectional area" before and so I used an online tool to convert the diameter (d) to cross-sectional area (A):

    http://www.sengpielaudio.com/calculator-cross-section.htm

    Or is that completely wrong?
    I'm sure I could be competent given the right instructions. Just not too familiar with the terminologies etc. and so just picking stuff up as I go.

    lol. I assumed that a certain number of amps would be required for x amount of outlets and so thought it relevant to share the number of outlets I would be requiring power for.
     
  14. EFLImpudence

    EFLImpudence

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  15. neljan

    neljan

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    Thanks, although it still baffles me :)

    From what I can tell the powered cable is 2.5mm² (it's overall Dimensions are 10mm x 6mm).

    The DB's non-connected cable is much thicker. It has a black outer sheathing and then a white sheathing inside it. The black sheathing has "3x6 mm²" printed on it. it's approximately 14mm in diameter.
     
  16. EFLImpudence

    EFLImpudence

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    Does it have steel wire under the top sheath?
     
  17. neljan

    neljan

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    Nope.
     
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