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Changing two way light switch

Discussion in 'Electrics UK' started by gerryb, 27 Jul 2021.

  1. gerryb

    gerryb

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    I’m changing a two way light switch in the hallway and want to be sure I’m doing it right.

    the old one - pictured is labelled common and has a horizontal layout the new one, also pictured, is labelled L and has vertical layout

    I’m assuming it’s a simple like for like with the two L1 and L2 wires

    my question is really about the black common wire and the red common wire and if it makes any difference how I swap them to the two new L terminals

    nb I’ll also be adding earth wire to the switch plate.


    Would appreciate your help.
     

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  3. ktuludays

    ktuludays

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    Yes, looks as you described
     
  4. terryplumb

    terryplumb

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    Your old switch doesn't have the "horizontal layout " that you think. It is exactly the same layout as the new one . Three terminals in a triangular format ,at each side.
     
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  5. 333rocky333

    333rocky333

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    You MUST keep the Red and Black with there relevant L1 and L2
    As above the 3 cables are in TWO triangle formats (One is inverted) NOT in line as you suggest.
    The new switch also has TWO triangle formats, however they are both same way up
     
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  6. bernardgreen

    bernardgreen

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    upload_2021-7-27_17-54-13.png
     
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  7. gerryb

    gerryb

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    That makes sense!
    Thank you
     
  8. ericmark

    ericmark

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    The Com/L is important must be correct, swapping L1 and L2 only swaps if up for on or down for on, it still works.
     
  9. gerryb

    gerryb

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    Supplementary question

    Top floor switch is the end of this circuit and controls pendant light in centre of room and the landing ligh in the hallway outside that room

    Wire had become detached as I discovered when I removed the old switch plate

    But there are only five wires not the six I would need to crest the inverted triangles illustrated above.

    Both lights used to work so what configuration would make the new switch control both lights once more?

    Thanks again in Advance
     

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  11. EFLImpudence

    EFLImpudence

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  12. gerryb

    gerryb

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  13. EFLImpudence

    EFLImpudence

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    No.

    I have indicated that you should move the red wire as per the arrow.
     
  14. gerryb

    gerryb

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    Got it. Thank you.
     
  15. gerryb

    gerryb

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    So that’s given me power to the landing light but not the pendant in the room.

    is there not an issue with having five wires not six?

    and believe me I’m two months in trying to book an electrician to do this!
     
  16. EFLImpudence

    EFLImpudence

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    That should be the bedroom light switch.

    Can we have another picture showing both the switch connections AND the cables coming out of the wall?
     
  17. gerryb

    gerryb

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    I’ve attached one with the right hand wires update as per the earlier advice. As you can see there are five wires, not six
     

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