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SWA ref method

Farmboy
Hi all, a 6mm2, 3 core, XLPE SWA cable lays in a void under a bungalow ground floor (the sub floor is concrete, with 450mm stub walls, on which sits wooden floor joists and wayrock wooden flooring - the swa lays unclipped/loosely on that concrete floor). So, what reference method and ccc table should be used in apdx 4?


F.
  • Former Community Member
    0 Former Community Member
    Clipped direct I guess (although not actually clipped in this case)


    Regards


    OMS
  • 0
    In terms of airflow, the cooling will be more like tray , as clipped direct is normally to a vertical wall not a horizontal one - is the rating so close to the rated load that this matters ? - if not and you just need a number for the 'rating of cable' column, then assume which ever of the cases has the lower value.
  • 0

    mapj1:

    ...if ... you just need a number for the 'rating of cable' column, then assume which ever of the cases has the lower value.




    Cutting a story short, it's just a 16A cct for an outdoor socket, so do you mean assume ref method D?


    F

  • 0
    Over sized ?


    Andy B
  • 0

    Sparkingchip:

    Over sized ?


    Andy B




    Quite so (apparently it was always meant to be for just two outdoor twin sockets, with minimal load), cable was installed by others who didn't return (customer won't say why - he's part paid me for works to date so doubt it's because of non payment, unless it's because the other didn't get full payment, but time will tell). 


    F

  • 0
    Worst case Table 4D4A RM D = 46 A so no problem at all.
  • 0
    Why not use a 32-amp protective device?


    If you use a B16 MCB it could trip when some garden equipment is used, if you want to stick to a 16-amp MCB it will probably need to be a C16.


    Andy Betteridge
  • 0
    Well at that size you could probably have a 45 A breaker and protect the cable more than  adequately - I presume that either the folk who fitted it were  going to come back and add a lot more load, or they were using up an offcut or  perhaps skip salvage  from another job. If need be, problems with tripping on inrush - if they do welding outside or something-  a 32A MCB or RCBO could safely be substituted.

    Clipped direct to a vertical wall would be about 60A, and as this is not quite as well ventilated perhaps 50 odd. plenty in hand.

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