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Wiring an isolator switch with 3 Core SWA

Discussion in 'Electrics UK' started by mcquitmp, 13 Sep 2007.

  1. mcquitmp

    23 Jul 2007
    Thanks Received:
    United Kingdom
    I have a 4 pole 32A Rotary Isolator switch which I am planning to use to Isolate the supply to a Hot Tub. The supply is fed from a 3 Core 6mm2 SWA cable.

    The Isolator switch is obviously designed to switch 3 phase and Neutral and has two other earth connection points.

    My question are -

    Why is the Neutral connection point smaller than the other 3 connection points (It does not indicate neutral on it but it seems a safe bet) - allowing only a smaller cable to be connected to it?

    Can I use one of the phase connection points to switch the neutral instead since I am only single phase anyway?

    I assume I connect the 3rd core (used as Earth) along with the Armour to the earth connection points and this remains unswitched?

    The switch is CED Rotary switch supplied by screwfix.

    Advice appreciated.

    After I have finished the complete installation will be inspected, tested and certificated by a Part P qualified electrician - but I'm trying to get it right from the start and don't want to look a complete idiot.

  2. JohnD

    15 Nov 2005
    Thanks Received:
    In 3-phase supplies the Neutral carries either no load, or a reduced load.

    If you are switching a single-phase circuit use two of the Phase contacts.

    The earth must be unswitched.

    the armour must be earthed at least at the supply end.

    If you are in England this is notifiable work and not very suitable for an amateur. the qualified electrician is supposed to install it, and test and certify his own work. Only a local Goverment inspector can inspect and certify someone else's work, and will have to see it during installation as well as at completion. You have to notify before starting work.

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