SWA sub-main

Discussion in 'Electricians' Talk' started by seneca2, Nov 6, 2010.

  1. seneca2

    seneca2 New Member

    Hi all,
    Just a quick question, 16mm SWA sub main, 25 metres long Henley'd off from meter tails, does it need a switch-fuse at the supply end? i'm thinking not as it's SWA. Supply is TNCS.
     
  2. sinewave

    sinewave Screwfix Select

    Of course it does!
     
  3. spark&half

    spark&half Active Member

    Yes it will need a switch fuse at origin.

    ;)
     
  4. seneca2

    seneca2 New Member

    Thanks for the quick reply both, I realise now it was a dumb question but thought as it was SWA maybe not!
     
  5. sinewave

    sinewave Screwfix Select

    You shouldn't be connecting SWA direct to henlies anyway.

    16/25mm Tails from Henlies in to Metalclad S/F, fuse at 63/50A then gland SWA in to that.


    Simpleeeees! :)
     
  6. spark&half

    spark&half Active Member

    In real life terms this would never pose a problem, it just keeps lecy board happy, assuming you had a 60A head?..

    ;)
     
  7. spark&half

    spark&half Active Member

    Yep agree With above^^^^^^^^

    ;)
     
  8. seneca2

    seneca2 New Member

    You shouldn't be connecting SWA direct to henlies anyway.
    ----------------------
    I wouldn't have done that anyway sine I would have put the SWA into a steel adaptable box then tails to Henley.
     
  9. seneca2

    seneca2 New Member

    I suppose EDF wouldn't like it if I put my switch-fuse in their box would they?
     
  10. Removed 4

    Removed 4 New Member

    Just do it, Sen.

    There was a time when the EB jealously guarded their precious chipboard area - but no longer these days. They will neither know or care about it once you've done it.

    They used to have good reason for this of course, because they always reserved a spot for an E7 timeclock and other stuff should it be necessary in the future - but now the case is altered.

    Depending on the size of your service fuse, you might well be able to use a simple DP isolator without the need for a sw/fuse restrictor......

    Lucia.
     
  11. J.P.

    J.P. New Member

    I wouldn't do it Sen..many years ago after doing a re-wire the meter chappy told me to take my DB off the REC's board..luckily enough could swing it down and off the board. As for not using a switch fuse to protect the sub-main in the event that the cutout is ok for the rating of the cable..flipping heck Lucia that is rough luv.

    Not the sort of way us DIY chappies carry out stuff tbgh.
     
  12. seneca2

    seneca2 New Member

    I doubt whether a meter chappy would even know what it was these days JP, let alone have the right or inclination to tell you to remove it!
     
  13. J.P.

    J.P. New Member

    Evening Sen. I don't know nowadays M8..but I always use to keep stuff off the Rec's and indeed later on the DNO's board after the DB thing with the meter chappy.

    Maybe they might be a tad more complacent nowadays..I don't know tbqh Sen.
     
  14. Removed 4

    Removed 4 New Member

    OK JP, just supposing that the service fuse is a mere 60A - what restriction would you, as a DIYer, place on this sub-main? 40A? 30A? 20A?

    I served many years with LEB/EEB (latterly EDF) and we were quite protective of our meter boards then - but that isn't the case now.

    We never insisted on a further reduction of a sub-main feed provided that it was large enough and compatible with the service fuse.

    All that was then required, was DP isolation.

    Seneca will be OK to mount his Sw/fuse or isolator in the cabinet. No one cares anymore.


    Lucia.
     
  15. J.P.

    J.P. New Member

    Fair nuff Lucia and thanks. However yes after discrimination the switchfuse size might be a limiting factor on proposed at DB2 (mainly with ref to a 60 Amp cutout) but well thats the way it is. In other words appreciate what you are saying.
     
  16. seneca2

    seneca2 New Member

    It would be difficult to put it anywhere else JP, the meter box is in the outside wall of the lounge so a switch-fuse wouldn't look very nice in there, plus the fact that the SWA will have to go up the outside of the wall to get into into the loft, it's a bit of an unusual type of job, a great big old house that was once split into two and had separate gas & elec supplies installed. The owners now want to turn it back into one residence and have just one gas & one elec supply. The meter they are keeping is at the opposite end of the house to the consumer unit! The other consumer unit is already being fed from the meter that i'll be connecting to.
     
  17. J.P.

    J.P. New Member

    See what you mean Sen..as the two dwellings are now being made into one is the supply just going to be the one?..Ie one supply for the whole house and mot two?
     
  18. seneca2

    seneca2 New Member

    Yes that's the plan JP.
     
  19. J.P.

    J.P. New Member

    Nice one Sen..sounds like a good job M8.
     

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