New light fitting... Now the light is permanantly stuck on!

Discussion in 'Electricians' Talk' started by mattylomas1, Aug 20, 2014.

  1. mattylomas1

    mattylomas1 New Member

    I recently refit a ceiling light fitting which had been broken around 5 months ago. Upon de-isolating the electricity the light came on and now neither the upstairs or downstairs switch is operable so the only way to turn off the light is to remove the bulb or isolate the whole lighting circuit from the fusebox I Correctly wired the live neutral and earth wires into a junction box already attached Correctly to the house wiring. There were no other wiring options available in this location. The light in question already had 2 switches, one upstairs and one downstairs.... The downstairs switch is a double switch and still turns the other light on and off, ruling out the possibility of a faulty switch.... or so I assume.

    Any advice would be greatly appreciated,

    Many thanks

    Matty
     
  2. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    Well you've obviously mixed up a live with a switched-live, so you haven't wired it correctly at all.

    Mr. HandyAndy - Really
     
  3. malkie129

    malkie129 Screwfix Select

    Well Handy, easy to criticise, how about giving the bloke some guidance. :(
     
  4. unphased

    unphased Screwfix Select

    Agree with HandyAndy. :) You don't claim to have done "nothing wrong" when clearly you have. Without knowing how the junction box comes in to the equation how can we advise?
     
  5. seneca

    seneca Screwfix Select

    Yes Matty, you have clearly got some wires mixed up! Photo's of the junction box, light switch and light fitting wiring might help us.
     
  6. flateric

    flateric Well-Known Member

    Or get a spark on the case :)
     
  7. Oh all right then I'll do it. Typically a lighting circuit is like a daisy chain. So at your junction box you will have three identical twin and earth cables. One is the power in, one the power out and the other is the switch wire. The blue (or black) of the switch wire should have a brown (or red) sleeve or tape on it. The sleeve can easily be lost so the world weary amongst us mark the switch wire before dismantling. To identify the switch wire you will need an ohm meter. I can't think of any other safe way for you. Turn the power off. Separate your three t&e's. Test between the brown and blue (or red and black) of each cable. If all the lights on this circuit are switched off then you will get an open circuit reading on all the cables. In which case switch the light under test on and you should get open circuit on two of the cables and a very low reading on the other. This is your switch wire. If some of the lights on the circuit are on then instead of getting an open circuit reading you will get a high resistance due to the lamps but the switch wire will always have a 0.x ohm reading. Mark it with a biro before you forget. Obviously all the earths are sleeved and connected together. The neutral in, neutral out and the lamp neutral are connected together. The live in, live out and the brown (or red) of the switch wire are joined together. And the blue, sleeved brown (or black sleeved probably brown as nobody has any red sleeving these days) of the switch wire is connected to the lamp live.
    What you have probably done is to connect the live of the lamp to the live in and out rather than the switched live. If you had been completely clueless and joined all the blues and all the browns then there would have been a pop when you switched the lights on!
     
  8. mattylomas1

    mattylomas1 New Member

    Thanks to noohmtogoto, the light and switches are now working. Thank you for exercising patience and taking the time to share your knowledge noohm.
    Everybody else..... try harder next time.
     
  9. JP.

    JP. Screwfix Select

  10. flateric

    flateric Well-Known Member

    Well done that man ... woman .... person ... I was going to say the same but I had beer and watched tv instead :D
     
  11. unphased

    unphased Screwfix Select

    We are probably bored with the same old lighting questions. Always the same mistakes, always "I didn't alter anything honest guv" type stuff. So we like to have fun with the boring stuff.
     

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