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Switched neutral

Harry Macdonald
Looking at the BS7671 AMD2 out for consultation, I noticed clause 463.1.2. This shows an arrangement whereby the control device for a lighting circuit is switched by a switch on the neutral side of the device.

Clearly this works but why would anyone want to do this?
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    but I am not seeing how switching the neutral "saves an extra wire out to the rooms".

    If switching in L for a relay you'd need L to the switches and SW back to the relay coil, then SL and N to the lights - so 4 conductors in all (plus any c.p.c.s). By allowing N switching you only need N & SW to the switches then SL to the lights - no 4th wire as you already have N handy - you save on the perm L.


       - Andy.
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  • 0
    but I am not seeing how switching the neutral "saves an extra wire out to the rooms".

    If switching in L for a relay you'd need L to the switches and SW back to the relay coil, then SL and N to the lights - so 4 conductors in all (plus any c.p.c.s). By allowing N switching you only need N & SW to the switches then SL to the lights - no 4th wire as you already have N handy - you save on the perm L.


       - Andy.
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