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Looping 16mm through a main switch

aligarjon
I need to split a 16mm t+e to feed a second CU.  Loading is not an issue.  Does anyone see a problem with me looping them through the 100 amp main switch.  2 16mm cores sit very nicely side by side and makes things a whole lot simpler and tidier.  The CU instructions say that the main switch will take up to 50mm.



Gary
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    It "sort of sounds poor practice" but I see no reason to actually prohibit what you propose. Make certain that there is enough room for the extra cable, not just terminal capacity but also wiring space.
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    I don't see why it can't be done (ideally confirm with the manufacturer that they support it being used in that way). Either way some extra care might be needed - the usual cage clamp terminals are dodgy enough with course stranded cables - having two cables so that half the strands could potentially move independently of the others might have a higher risk of coming loose when the wiring is disturbed. I think I'd be happier if it were twin screw tunnel terminals rather than cage clamps.


    I've a vague recollection of a terminal that took two conductors and provided a solid pin for a cage clamp terminal - but being neither my memory or Goggle can find it now, they must be pretty rare.


       - Andy.
  • 0
    Is this because you need to have the two CUs side by side?


    What will be the OCPD for these cables?


    Might it not be better to use a 63 A MCB?
  • 0
    Manufacturers do similar looping internal tails through RCDs, so in principle I don’t see an issue.


    However the manufacturers do use different types of cable, fine multi-stranded, and ferrules for the internal tails.
  • 0
    aligarjon:

    I need to split a 16mm t+e to feed a second CU.  Loading is not an issue.  Does anyone see a problem with me looping them through the 100 amp main switch.  2 16mm cores sit very nicely side by side and makes things a whole lot simpler and tidier.  The CU instructions say that the main switch will take up to 50mm.



    Gary


    Reply through a hazy early morning brain. I seem to remember that some Wylex 100 Amp switch fuses had twin main terminals for this very purpose. Supply in-loop out.  Many years ago I added additional tails to fuse boxes that were fully occupied, for a new circuit like a new cooker of shower circuit. Back in the days of 16mm2 tails additional 6.0mm2 tails could be shoved up into the twin screw main switch terminals for a new switch fuse for a new circuit. It was a perfect tight fit and worked perfectly. All strands had to be parallel and not twisted.



    Or there is always the option of the good old Henley block.


    Z.


     


  • 0
    Wylex "Extenso" Zoom lad?.

    Yes the cage clamps of today are poor compared with the old double screws tunnel terminals of yesterday and I`d be thinking tail block in first instance
  • 0
    Wylex 304/306, in those days usually coupled with 2way csu but could be anything like a 4 or 6 way

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