Need help replacing ceiling light

Discussion in 'Electrics UK' started by m1l4n, 25 Apr 2014.

  1. m1l4n

    m1l4n

    Joined:
    25 Apr 2014
    Messages:
    5
    Thanks Received:
    0
    Location:
    London
    Country:
    United Kingdom
    Hi,

    I just recently bought a house and I am trying to replace the light in the bedroom with a new one but I can't get the switch to work.

    I've got 2 black, 2 red (joined together) and an earth wire as in the below image:


    I am tring to connect the below light fitting:


    This is what happens when I connect the wires:

    Black#1 & 2 Red --> light is always on (regardless of the switch)
    2 Red & Black#1 --> light is always on (regardless of the switch)
    Black#2 & 2 Red --> no light
    2 Red & Black#2 --> no light
    Black#1 & Black#2 --> no light

    Black#1 is the one that lights up when I use a tester.

    Please help, I have been stuck on this for 3 days now! :( What do I need to do to get it working?

    Thanks in advance.
     
  2. Sponsored Links
  3. PrenticeBoyofDerry

    PrenticeBoyofDerry

    Joined:
    30 Jun 2009
    Messages:
    21,627
    Thanks Received:
    2,382
    Location:
    Londonderry
    Country:
    United Kingdom
    Are you sure that Black 1 is always live and not one of the reds?
    Does black 1 come live only when the switch is closed and then dead when open.
    As the normal set up would be for one black to be neutral posible black 2 in your case.,
    The the second black to be the switch live (should be ID by red tag, but not always done).

    One of the reds would be permanently live and the second red would go through to the switch, and return via the switch live.

    So you need to ID your perm live and your switch live and neutral.

    *In most cases the two reds would be connected together as one would be perm live and the second to the switch.
    They are not connected across the light, so you require a separate connector (do not twist together and tape up).
    *Then the switch live goes to the Live side of light (could be black 1).
    *And the neutral (possibly black 2) to the neutral side.
    *all earths to earth terminal, if no earth terminal on fitting, they must be kept terminated together to keep continuity around the circuit, so again a separate connector and all together.

    Once you have done this it is advised to check you have kept earth continuity around the circuit and all earths are terminated making good contact.

    Please note neon type test screwdrivers are not a good or safe method of testing for live, use a two pole/probe tester.

    If you look at the image below and exclude the cable going to the next fitting, this would be similar to what I would expect you to have.

     
    • Thanks Thanks x 1
  4. m1l4n

    m1l4n

    Joined:
    25 Apr 2014
    Messages:
    5
    Thanks Received:
    0
    Location:
    London
    Country:
    United Kingdom
    Thanks PrenticeBoyofDerry

    The diagram you have is exactly what I thought I should be doing, I joined the 2 reds, and connected the 2 blacks to the light fitting but there is no light. The 2 blacks are identical and I couldn't distinguish visually which one is the switch live. But this didn't work regardless of the switch being on or off. I tried several times and swapped the blacks around but no light whatsoever. I am wondering if some of the cable got damaged while I removed the old light.

    I will get a probe and try again, will update tonight.

    Thanks
     
  5. DaftPunk

    DaftPunk

    Joined:
    25 Jun 2012
    Messages:
    565
    Thanks Received:
    111
    Country:
    United Kingdom
    Do you have a dimmer switch? As you've connected both reds and both blacks together you've created a perfect short circuit which 1000's of amps will have flowed through destroying any dimmers sand possibly even a normal light switch.
     
    • Thanks Thanks x 1
  6. m1l4n

    m1l4n

    Joined:
    25 Apr 2014
    Messages:
    5
    Thanks Received:
    0
    Location:
    London
    Country:
    United Kingdom
    Yes I do have a dimmer switch :oops:

    So if I replace the switch it should work?
     
  7. winston1

    winston1

    Joined:
    11 Jan 2010
    Messages:
    7,342
    Thanks Received:
    572
    Location:
    London
    Country:
    United Kingdom
    I've read through this thread thoroughly and nowhere has he/she said that he/she has connected both blacks together.
     
  8. Sponsored Links
  9. m1l4n

    m1l4n

    Joined:
    25 Apr 2014
    Messages:
    5
    Thanks Received:
    0
    Location:
    London
    Country:
    United Kingdom
    Hi winston1,

    Although I didn't mention it in the post, I did do that at one point, I connected both blacks to one point on the new light fitting with the 2 reds on the other.

    I got so frustrated, I tried every combination possible! I did replace few lights in my previous place but that was a brand new flat which only had a brown and blue wires.
     
  10. PrenticeBoyofDerry

    PrenticeBoyofDerry

    Joined:
    30 Jun 2009
    Messages:
    21,627
    Thanks Received:
    2,382
    Location:
    Londonderry
    Country:
    United Kingdom
    Sounds like you have fried the dimmer switch then, a replacement will be needed, just to add in future take a note of existing conductors and the terminal markings, label up the cables as it helps. Also testing is important, so get a two probe tester and do not energise until you have proved it is safe to do so.
     
  11. Taylortwocities

    Taylortwocities

    Joined:
    28 Jul 2006
    Messages:
    20,632
    Thanks Received:
    2,141
    Location:
    Oxfordshire
    Country:
    United Kingdom
    Replace the dimmer with a standard light switch while you get the light working.
    Once that is OK, go buy a new dimmer.
     
    • Thanks Thanks x 1
  12. m1l4n

    m1l4n

    Joined:
    25 Apr 2014
    Messages:
    5
    Thanks Received:
    0
    Location:
    London
    Country:
    United Kingdom
    Thanks everyone, bought a 50p normal switch and it worked!
     
  13. PrenticeBoyofDerry

    PrenticeBoyofDerry

    Joined:
    30 Jun 2009
    Messages:
    21,627
    Thanks Received:
    2,382
    Location:
    Londonderry
    Country:
    United Kingdom
    The magic of 50p accessories :mrgreen:
     
  14. DIYnot Local

    DIYnot Local

    Joined:
    3 Sep 2019
    Country:
    United Kingdom

    If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

    Select the supplier or trade you require, enter your location to begin your search.


    Are you a trade or supplier? You can create your listing free at DIYnot Local

     
Loading...

Share This Page