Changed Light Switches - Now Not Working

Discussion in 'Electricians' Talk' started by EasyPeasy123, Sep 29, 2022.

  1. EasyPeasy123

    EasyPeasy123 Member

    Hello all.

    I decided i would change all of the light switches and power sockets in my house as the previous owners ended painting all over them and they looked a mess.

    Changed the the second floor light switches and everything is good. Started on the 1st floor and stopped half way to run some errand. Came back and finished but now the lights do not work at all on the 1st floor and one room on the 2nd floor.

    The ground floor lights are fine.

    Is it likely I’ve wired something wrong? I’m fairly certain I put the wires in the their equivalent hole on the new switch.
  2. FlyByNight

    FlyByNight Screwfix Select

    Picture of teh wiring before and after?
  3. EasyPeasy123

    EasyPeasy123 Member

    I normally take a before just in case but for some reason, didn’t do it
  4. terrymac

    terrymac Screwfix Select

    Are all 3 floors on the same lighting circuit ?
    Show us a pic of the wiring of the first switch that you worked on at 1st floor .
    Do you have any voltage testing instruments ?
  5. EasyPeasy123

    EasyPeasy123 Member

    Each floor is on a separate breaker. Thought one had tripped but they were fine.

    I only have a voltage tester pen from Screwfix.

    I’ve attached a pic of the first switched I changed over (but all were changed).

    Oddly, one of the light switches, which was a dimmer switch, had two connections, one going in to L1 and the other in to L2 :-s

    31FA6107-B1B0-4A73-BE17-40B4C200D835.jpeg E0C3CF8E-92DD-406B-9967-861C8CCCEF9C.jpeg
  6. Ind spark

    Ind spark Screwfix Select

    If all them are mixed up its gonna be hard to sort that on here, your gonna need a sparky.
  7. Ind spark

    Ind spark Screwfix Select

    What cables do you have there? Is it 2 x 3 cores(red, yellow, blue)
    And 2 x 2 cores (twin red)
  8. arrow

    arrow Active Member

    The picture you show does not have the face plate earthed. If the new switches are metal, you need to terminate the earth wires in the face plates and then put a link from face plate to the back box.
  9. EasyPeasy123

    EasyPeasy123 Member

    Thanks for the replies.

    The face plates for the light switches are plastic.

    1x red in each COM.

    Switch for 1st floor landing:
    L1 1x red 1x blue
    L2 2x red 1x yellow

    Switch for 2nd floor landing:
    L1 1x blue
    L2 1x yellow
  10. FlyByNight

    FlyByNight Screwfix Select

    The plate the switches on are metal and MUST be earthed even with a plastic snap on cover.
  11. EasyPeasy123

    EasyPeasy123 Member

    Thanks for the info. I’ll sort that out now
  12. Ind spark

    Ind spark Screwfix Select

    Are both switches in the picture not working?
  13. EasyPeasy123

    EasyPeasy123 Member

    The switch for the 2nd floor landing works but none of the 1st floor lights work.
  14. Ind spark

    Ind spark Screwfix Select

    So which switch isnt working left or right
  15. EasyPeasy123

    EasyPeasy123 Member

    The left one in that pic.
  16. Ind spark

    Ind spark Screwfix Select

    What is it doing that it shouldnt.

    It's a 2 way switch so in the other switch (at the other side of the corridor or wherever it is) there will probably be a 3 core, make sure the colours are in the same terminals as this switch.
    If that makes sense.
  17. terrymac

    terrymac Screwfix Select

    With circuit breakers OFF for all lighting circuits except the first floor which should be ON, is your voltage stick showing voltage present at any first floor switch ?
  18. EasyPeasy123

    EasyPeasy123 Member

    Yeah, it is a two way switch. The left switch operates the 1st floor landing light and the right side switch operates the 2nd floor landing light. 2nd floor landing light is working fine from the 1st floor switch or the 2nd floor single switch.

    I've added a pic of the 2nd floor landing switch and it appears everything is in the same positions.

    Attached Files:

  19. terrymac

    terrymac Screwfix Select

    If only one room on second floor has its light not working ,that's not going to be associated to no First floor lighting working at all. You need to establish voltages present.
  20. EasyPeasy123

    EasyPeasy123 Member

    Problem solved. Thanks for all the help, you guys are great!

    Turns out it was the wiring which had been done by the previous owner (I've only just moved in). It was the dimmer switch wiring. Put those in the correct terminals and all the lights are working.

    An extra thanks to FlyByNight for the info regarding earthing the boxes.

    I will be getting a safety cert check on the property in just over two weeks once other works are finished for some peace of mind.

    Thanks again.
    Ind spark likes this.

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