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Another light switch question

Discussion in 'Electrics UK' started by lukea, 11 Apr 2019.

  1. lukea

    lukea

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    So whilst replacing old light switches with new ones (nothing fancy this time just replacing scruffy ones with white ones) 2 rooms in my house have 2 wires going in to one of the ports and 1 wire going into the other. One has 2 into common and 1 in to l1 and the other 2 in to l1 and 1 into common. I’m assuming one of the switches is wired incorrectly and am curious as to why they would be wired like this? Again an assumption is that this is to continue the circuit through the house but why do this at the switch and not in one of the junction boxes? Help appreciated!
     
  2. EFLImpudence

    EFLImpudence

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    Really we need to see what other wires, if any are in the enclosure.
    It could be the two wires go to two lights.

    With one-way switches it doesn't matter which way round they are.

    What do you mean "one of the junction boxes"? How many are there?
    Why use an unnecessary junction box when it can be done at the switch?
     
  3. lukea

    lukea

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    Thanks for the swift reply. There are halogen spots in the room. Could it be that the room has been split in to two sets of lights? There’s only one switch and it switches on all of the lights in the room. The wires are all grey externally with red internal insulation.
     
  4. lukea

    lukea

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    And reference to the ‘when it can be done at the switch’ I’m not an electrician so am
    Curious as to why it’s done at the switch and not elsewhere. Don’t know if it is right or wrong. My loft has quite a few junction boxes...
     
  5. EFLImpudence

    EFLImpudence

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    It could be.

    Well, your question is not really valid.

    You might as well ask "Why do it at a junction box or elsewhere when it could be done at the switch?"

    Ok.

    DIYers seem to love junction boxes. I don't know why. Perhaps they don't realise wires can be connected at switches and fittings.
     
  6. lukea

    lukea

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    I’ll trace all the wires to get a better idea, but assuming it’s one set of lights, why would I have 2 wires to one of the ports? Is typically as I initially thought? That is keeping the circuit when the switch is off?
     
  7. EFLImpudence

    EFLImpudence

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    If that assumption is correct then it is likely that the neutrals would also be present and connected together.

    Two wires in one connector could be, as said, they go to two (lots of) lights,
    one used to be for that and now both are connected together at both ends - just because it can be, as it is safe for spare wires.

    Disconnect one and see what stops working.
     
  8. DIYnot Local

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