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  1. TomSparkman
    Offline

    TomSparkman Active EF Member

    Location:
    Manchester
    Hi all,

    Went to a house on friday due to sub-main to shed not energising. This was simply due to the MCB playing up. I flicked it on and off a few times and it works fine now.

    However im not happy with the way the submain has been installed poorly.

    The sub-main is in the form of a 3 core SWA. It isnt buried properly as i can see it in some places and the armour isnt earthed. Only the end at the shed D.B is made off using a gland and the supply end in the house is just coming through the wall in to a 4x4 box and in to the C.U on top.
    The SWA is rcd protected in the house but the small 2 way D.B in the shed is not.
    The shed has a few sockets and lights and i believe the customer intends to plug in a jacuzzi which will be inside the shed.

    1. Does the SWA that runs outside have to be RCD protected?

    2. Is it ok to have the RCD in the house, protecting both the sub-main and the circuits in the shed?

    I advised the customer that the submain was potentially dangerous due to installation methods.
    I also advised to fit IP sockets in the shed due to being in close proximity to the jacuzzi
     
    • Disagree Disagree x 1
  2. westward10
    Online

    westward10 Please don't bore me with your life story. Electrician's Arms

    Location:
    Northamptonshire
    If the swa has fault protection with the rcd removed then probably no. Is the armour not earthed at all.
     
  3. Vortigern
    Offline

    Vortigern Electrician's Arms

    Location:
    England
    Business Name:
    F.H. Electrical
    That all sounds so wrong. The SWA made off at the garage end, wrong, should be the other end, assuming a TT arrangement at the garage. S type RCD for supply and RCD in the garage with TT arrangement. As for sockets anywhere close to a Jacuzzi, I don't think so. Seems like a recipe for a bad accident waiting to happen. You did not say what the supply is i.e. TNS or???
     
    • Agree Agree x 1
  4. davesparks
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    davesparks Trusted Advisor

    Location:
    guildford
    How do you know that the mcb is fine now? How do you know that it is not damaged internally?

    SWA need only be earthed at on end if not used as the cpc.

    What's wrong with being able to see the SWA?

    How can you say the DB in the shed is not RCD protected if the submain is RCD protected?

    Without the necessary information I cannot say whether the SWA needs RCD protection or not, it may require it for fault protection is the efli is too high.

    I don't think you are justified in telling the customer that this circuit is dangerous and though it appears to be through lack of knowledge it could be viewed as the bullying tactic of a cowboy.
     
    • Agree Agree x 3
    • Like Like x 2
  5. Leesparkykent
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    Leesparkykent You Rock Gmes Staff Member Trusted Advisor

    Location:
    Kent
    By flicking the mcb on and off you may of blown the fault clear and potentially left it in a dangerous situation. The only time the Distribution circuit may need to be on an RCD is if the earthing arrangement is TT or if TN and can't meet disconnection times due to poor design. If the distribution circuit is on an RCD then there would be little point in putting the final circuits at the far end on another RCD as you are not going to achieve discrimination/selectivity. With regards to the earthing of the armour of the SWA it's ideal to do it at the front end but if it's earthed at the far end then it's not really an issue. With regards to the buried depth of the cable is it likely to be damaged?
     
    • Agree Agree x 4
  6. TomSparkman
    Offline

    TomSparkman Active EF Member

    Location:
    Manchester
    The supply to the house is TNCS. The SWA is fed from the C.U in the house, to the shed(no gland at this end).
    It goes in to the shed after being lightly covered by soil on it journey across, and goes in to a proper gland but no banjo! So the armour braiding is not earthed.
     
  7. davesparks
    Offline

    davesparks Trusted Advisor

    Location:
    guildford
    A banjo is not the only possible means of connecting to an SWA gland.

    If it has braiding then it is not regular SWA.
     
  8. bigspark17
    Online

    bigspark17 Electrician's Arms

    Location:
    wales
    Are you an electrician? not sure how you can give paying customers this advise and then ask on here you cant be sure so why advise customer its dangerous?!
    flicking an mcb on a few times is not a proper fault finding process, testing the submain first would have been a better approach.
     
    • Agree Agree x 2
  9. TomSparkman
    Offline

    TomSparkman Active EF Member

    Location:
    Manchester
    I havent "blown the fault clear". I know this as i removed the MCB before flicking it a few times.
     
  10. TomSparkman
    Offline

    TomSparkman Active EF Member

    Location:
    Manchester
    How else would you propose to earth the armouring if at both ends the D.B/4x4 box are plastic???

    I also performed insulation resistance tests on both circuits withing the shed and the SWA sub-main which came up clear. Sufficient Zs reading from all circuits also.
     
  11. wirepuller
    Offline

    wirepuller Trusted Advisor

    Location:
    south uk
    I note you have given advise on the sockets 'in close proximity' to the Jacuzzi.
    Are you aware of the actual requirements for the siting of sockets in such a situation? Does the siting of the sockets meet the requirements?
     
  12. Leesparkykent
    Offline

    Leesparkykent You Rock Gmes Staff Member Trusted Advisor

    Location:
    Kent
    piranha nut.
     
    • Like Like x 2
    • Agree Agree x 2
  13. davesparks
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    davesparks Trusted Advisor

    Location:
    guildford
    I use earthing nuts on SWA glands
     
    • Agree Agree x 1
  14. wirepuller
    Offline

    wirepuller Trusted Advisor

    Location:
    south uk
    Wiska supply a twin earthing plate for their boxes....much easier than effing about with a banjo.
     
    • Agree Agree x 4
  15. TomSparkman
    Offline

    TomSparkman Active EF Member

    Location:
    Manchester
    There is no jacuzzi yet, but he said he wants to put one in there. Its 3.5 metres from the edge of the jacuzzi as it is above ground level, also must me 30ma rcd protected
     
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