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Power cable to shed

Discussion in 'Electrics UK' started by Bigtree, 8 Jun 2019.

  1. Bigtree

    Bigtree

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    i am wanting to lay some armoured cable down my garden to two sheds and some decking. What size cable should I use and how deep does it need burying?

    Obviously I will get an electrician to do all of the technical bits when needed

    Thanks for and help/advice
     
  2. winston1

    winston1

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    It all depends on what load you will need and how far it is. Why don't you ask the electrician that you are going to use? Don't forget this is notifiable work so you or your electrician will need to involve building control before you start.
     
  3. Simon35

    Simon35

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    Sizing the cable and knowing how deep to bury it are technical bits, so obviously you will now get an electrician.
     
  4. Bigtree

    Bigtree

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    Yes boss (y)

    Here’s me thinking the connecty uppy to the big bad box in the garage with the exciting flicky switch bits was the technical stuff
     
  5. bernardgreen

    bernardgreen

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    That is about 50% of the tekky stuff.
     
  6. john4703

    john4703

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    but if BigTree does all the digging of the trench (to the depth his electrician specifies) it will save him a lot of £s
     
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  7. EFLImpudence

    EFLImpudence

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    It is, but there is also the legal bit.

    If you want someone to sign the bits of paper, ask them where they want the cable run etc.
     
  8. john4703

    john4703

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    I agree and in my post above I assumed the electrician would specify the route as well as the depth.
     
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  9. ban-all-sheds

    ban-all-sheds

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    I being the person responsible for the design, construction, inspection & testing of the electrical installation (as indicated by my signature below), particulars of which are described above, having exercised reasonable skill and care when carrying out the design, construction, inspection & testing hereby CERTIFY that the said work for which I have been responsible is to the best of my knowledge and belief in accordance with BS 7671:2018, except for the departures, if any, detailed as follows:
     
  10. Simon35

    Simon35

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    You thought wrong, and here's me thinking that you were never getting an electrician in the first place.
     
  11. Notch7

    Notch7

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    The cable size is determined by the cable length and the total load.

    Specifying is quite technical because for various reasons voltage drop in the cable must be within certain limits.
    The cable must be able to cope safely with the maximum load as restricted by the mcb.

    But the electrician also needs to choose the correct earthing requirement as that will influence the cable spec too.

    And rcd protection needs consideration.

    Whilst you wait to hear back from your electrician, this calculator will give you an indication:

    https://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html
     
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  12. Simon35

    Simon35

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    And the type of cable, and the method of installation etc etc, which you know, but our OP doesn't.
     
  13. John D v2.0

    John D v2.0

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    The general guidance would be bury it deeper than anyone would be digging, and put marker tape (cables below, danger) and a layer of sand above the cable.
    If the cable is below a patio you may not need to go as deep as in a vegetable patch.
    Also bury it somewhere unlikely to be disturbed eg the edge of the plot, and leave a diagram of the route with the rest of the documentation.
    Regarding the size, the electrician will decide after doing some calculations and measurements. Could be anything from 1mm 2 core for a few lights near the house, to 16mm 3 core for a growing operation at the bottom of the garden.
     
  14. bernardgreen

    bernardgreen

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    upload_2019-6-9_13-51-49.png
    Across my yard, two ducts to the outbuildings, one for SWA to be pulled through and one for ELV cables.
     
  15. AndyPRK

    AndyPRK

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    And if you were to use 6mm swa should be ok for average needs
     
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