Basic electrical question

Discussion in 'OT (OFF Topic) Forums' started by Gollom, Nov 21, 2008.

  1. Gollom

    Gollom Hardcore MB Enthusiast

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    Want to run power to my shed (not huge amounts - a light, drill and maybe a small fire now and then) The cable will run where there is no chance of it being dug up/interferred with etc. so would it be OK to use an uninterrupted run of basic twin & earth (I have a reel of the flat grey stuff) inside conduit/trunking? (don't want to go to the expense of armoured cable if I don't need to) I'd get someone qualified to connect up the final mile to a seperate fuse in the mainbox.
     
  2. Meldrew2

    Meldrew2 Hardcore MB Enthusiast

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    Funnily enough, you'll pay more for conduit than you would pay for armoured cable.

    Suggest 1.5mm SWA cable, which will take 13 amps, and you can take it into a weatherproof twin socket in the shed, supplying it via a 13 amp fused spur (with RCD protection if ring main not already protected) from the nearest socket outlet... no need to go all the way to the fuse box for a small load.

    However, by "connecting the final mile", the electrician is taking responsibility for the complete installation (under BS 7671 and Part "P" building regs) so you may have trouble getting a good electrician to do the job... I know when I was "on tools", even before Part "P", I would have refused the job.
     
  3. verytalldave

    verytalldave Hardcore MB Enthusiast

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    You cant bury "ordinary" non protected cable. Its illegal AND dangerous.
    You can run it buried in either plastic or steel conduit designed for the purpose.
    An alternative is to run it above ground fixed by cable clips every 300mm or so.
    And use a RCD/earth leakage detector whenever you run power out the home.
    Do that and you can simply plug in to a convenient socket and not wire into the main box.
    I would use 2.5mm Twin and earth as a minimum. That will be more than OK for use up to the 13amp fused maximum.
     
    Last edited: Nov 21, 2008
  4. Mr E

    Mr E Hardcore MB Enthusiast

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    Part P also puts the garden into the same category as kitchens and bathrooms and needs a "competent person" to install and certify.

    No problems for day-to-day running, but you'll need to produce the cert when you come to sell the house (which may not bother you).

    I got the spark to put in a fused spur to my rear wall when he replaced our consumer unit - cost an extra £20. I then run the cable to the summerhouse from this socket - not a fixed installation. Pragmatic advice from the spark :)
     
  5. mattc

    mattc Hardcore MB Enthusiast

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    Steve, Like the other suggest do this as a 'temporary' power supply. Avoids all the nonsense of part p and if you ever sell up just take it with you as an extension cable.
     
  6. Howard

    Howard MB Club Veteran

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    When did part P come into force ? Is this the thing that was brought in in the last couple of years that needs a certificate for anything done ?

    What if it was done before the regs changed ?
     
  7. whizzkid11

    whizzkid11 Hardcore MB Enthusiast

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    Basic twin earth is DEFINITELY a no no.

    The has to be protected, and armoured cable is the only way to go. It should be switched/fused and the ring should be on RCD. The laws surrounding house electrics are now very strict as of a couple of years ago and continually getting stricter. Its for your safety.

    If you want to save money by cutting corners than I suggest you don't do it at all. If you are going to do it, the please, do it properly.
     
  8. Satch

    Satch Hardcore MB Enthusiast

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    Well it came into force just in time for our new kitchen and because of the scale of electrical works and a new consumer unit it meant we needed a full certification for the house: £600 including remedial work.

    Bit of a gripper but found out as a result that the upstairs lighting circuit and the mains sockets in the garage had no earth.
     
  9. portzy

    portzy Hardcore MB Enthusiast

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    All here

    Cheers.
    Portzy.
     

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