2 or 3 core

Discussion in 'Electricians' Talk' started by Aldiy, Sep 2, 2021.

  1. Aldiy

    Aldiy New Member

    Hi all , apologies if this isn’t the right place but I would appreciate a little advice .
    I want to replace complete spotlight units in bedroom from low voltage to double insulated 230v swivels .
    I have found individual transformers and junction box connection and disconnected before the transformer and I am left with approximately 1m of 2 core mains cable from junction box in ceiling.
    The question is can I connect the 2 core direct to the new light or should it be 3 core inc an earth to be safe ? I believe the new lights are class 2 double insulated.
    Apologies for long post and appreciate any advice
     
  2. Coloumb

    Coloumb Screwfix Select

    You mean the whole lighting ctt. is wiring in 2 core with no cpc? This would suggest a very old installation indeed in need of modernization. If that is so then what would you connect the cpc to if you used 3 core?
     
  3. Aldiy

    Aldiy New Member

    I believe it’s only 2 core from junction box to what was the transformer, the rest of house is 3 as normal , was 2 core used for power to low voltage spotlights?
     
  4. The Happy Builder

    The Happy Builder Screwfix Select

    Do the new light fittings actually have an earth terminal?
     
  5. Aldiy

    Aldiy New Member

    Yes they have one
     
  6. The Happy Builder

    The Happy Builder Screwfix Select

    If the light fittings are marked as double insulated then you don't need to use it, it is there as a parking terminal and to allow continuity on the circuit if you daisy chain the fittings.
     
    Aldiy likes this.
  7. Fusebox Wales

    Fusebox Wales Member

    For the sake of replacing a short length from the junction box, I'd use 3 core and take the earth to each point. It will be better for future R1 + R2 testing and the earth will be present if you ever need to chance the lights.
     
    Aldiy likes this.
  8. Aldiy

    Aldiy New Member

    as a matter of interest they are boxed at class 2 double insulated, but if I were to replace the feed to 3 core , is it ordinary 3 core lighting flex I’d need
     
  9. Aldiy

    Aldiy New Member

    And would that be normal 3 core for lighting or something special?
     
  10. Fusebox Wales

    Fusebox Wales Member

    Aldiy likes this.
  11. Aldiy

    Aldiy New Member

    Thanks for all the help , hopefully I’ll do it and it will be fine
     
  12. Aldiy

    Aldiy New Member

    Because wiring is already in place ,will the new lights be ok with the circuit breaker value in consumer unit ? As lights are now longer low voltage just a thought maybe over thinking
     
  13. sparky steve

    sparky steve Screwfix Select

    Should be a 6A.
     
  14. Fusebox Wales

    Fusebox Wales Member

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  15. Aldiy

    Aldiy New Member

    I’m about to start this project the twin core from junction box to light is thinner than wiring to the junction box , I does that sound right? . I tried to send an image, but can’t seem to reduce the image size
     
  16. Fusebox Wales

    Fusebox Wales Member

    It's possible that your existing light circuit is wired in 1.0mm instead of 1.5mm. If so, that's not a problem, you can still use 1.5mm twin & earth.

    https://www.fuseboxwales.net/
     
  17. Aldiy

    Aldiy New Member

    The thinner cable is from box to light , the wiring in ceiling looks normal size
     
  18. Fusebox Wales

    Fusebox Wales Member

    If you mean the cabling from the lamp holder to the connection box which is all part of the manufacturers pre-wired set up, yes that's fine. That short length of cable is only supplying x1 bulb and doesn't need to be as thick as the circuit cables.

    https://www.fuseboxwales.net/
     
  19. Aldiy

    Aldiy New Member

    This is the thinner wire I mentions from junction box in ceiling, to be connected to light connection. All connected and working fine so should all be ok . Thank you for all your advice sorry if been a pain !
     

    Attached Files:

  20. Bazza

    Bazza Screwfix Select

    Hard to tell, but that is probably 0.75mm2 flex. ok to use providing the CPD is no more than 6amp.
     

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