Wire Madness

Discussion in 'Electricians' Talk' started by Ryles, Jun 12, 2018.

  1. Ryles

    Ryles New Member

    so I've tried to replace the bathroom light fitting today but there is a crazy amount of wires and I'm confused.com

    what's worse is that now half the upstairs lights aren't working and the mrs is fuming - please help!

    There is one switched live, 4 earth, 4 live and 3 neutral.

    usually I just mirror what the old fitting had but if you look at the pics of the previously fitted light, the neutral and live are in the opposite terminals - crazy.

    Can anybody point me the right direction?
    Should it matter if all the neutrals and the live are in the same terminal?

    Attached Files:

    Last edited: Jun 12, 2018
  2. seneca

    seneca Screwfix Select

    If you know which one is the switched live that one will go to one side of the lamp, all the neutrals will go together and connect to the other side of the lamp and all 4 lives go together in a connector block, same with the earths.
  3. Ryles

    Ryles New Member

    you'd think but it's not working, makes me wonder why the previous fitting was wired back to front, makes no sense why the blue is going to switch live and brown to the neutral (see pic2)

    also can anybody explain why the other upstairs lights are no longer working?
    Last edited: Jun 12, 2018
  4. robertpstubbs

    robertpstubbs Active Member

    There are 4 red and 4 black. Presumably 1 of each are upstream, 1 of each are downstream, and 1 of each are for the loop-down switch. What are the others for - a fan?
  5. Ryles

    Ryles New Member

    yeah there is also a fan, silly question but do all live and neutral wires need to be touching in the same terminal, ie if I use a terminating block for the 4 live do they need to be together?
  6. DIYDave.

    DIYDave. Well-Known Member

    Not unusual to have a ‘crazy’ number of wires at the ceiling rose

    Also not unusual to have a crazy number of posts on lighting wiring issues !

    Must be some corrolation there I recon ?

    Likely that 3 cables are for lighting circuit and maybe 4th is feed to a fan or shaver socket or cabinet light - but doesn’t matter really

    As you say, live and Nuetral to light fitting are reversed at the rose. If a simple bulb and pendant / light fitting, although not right, this will have no effect and bulb will still light

    Can be dangerous with a screw cap bulb as outer part of lamp holder will now be live, instead of shielded center pin (again bulb will work, but bluddy dangerous

    What type of light have you now fitted and have you kept live/Nuetral reversed or corrected ?

    If uv fitted an led lamp / fitting, many will only work with correct polarity

    Are you sure that the red band on ‘switched live’ didnt slip off and uv mixed up the black cores ?

    Can test with a simple neon screwdriver if no other test equipment available

    And yes my suggestion will be ridiculed but if ur a diy’er like me, we ain’t got a garage full of Fluke and Megga testers but yes, we do have a neon screwdriver at our disposal

    Limited in use I fully understand but to ID switched live, it will do the biz :)
  7. DIYDave.

    DIYDave. Well-Known Member

  8. robertpstubbs

    robertpstubbs Active Member

    What sort of fan is it and how is it controlled - eg by the light switch?
  9. robertpstubbs

    robertpstubbs Active Member

    Not surprised you call yourself DIY.

    About 50 years ago it was common for fan to be wired in T+E from bathroom ceiling rose and be controlled by lighting switch.

    Don't know if relevant here, but I would like to know what every wire did before working on installation.
  10. Bazza

    Bazza Well-Known Member

    It’s simple

    The black with the red sleeve. That is the switched live. That goes to the live on the light.

    All the remaining blacks go together in one terminal. Also the neutral to the light connects to all these blacks

    The four reds all go together in one terminal

    The four earth wires all go together in one terminal

    Do that and report back. I can’t see where the fan connected on the old ceiling Rose. But we’ll done for taking photos before it was all disconnected.

    PS you may need the next larger size of terminal block!
  11. robertpstubbs

    robertpstubbs Active Member

    Don''t know whether it would have any bearing on current case, but it was previous practice that black coming back from switch was connected to red going to fan as well as being connected to light.

    If it was me I'd like to know what 4th set of T+E did.
  12. DIYDave.

    DIYDave. Well-Known Member

    Yep I am diy, don’t pretend to be anything else

    So are you saying that in the last 50 years, no bathroom fans have been wired in T&E from ceiling rose ?

    Next you will be saying that every fan ever fitted has been fitted exactly to the letter stated by manufacturer with isolator and/or 3A fuse protection

    I did say ‘maybe’ 4th cable is fan, shaver socket, cabinet light, etc

    Without testing you never know what’s been lashed up to the rose. Could be tv amp or even a shower pump ? Who knows eh ?
  13. peter palmer

    peter palmer Well-Known Member

    50 years ago they used to **** in a bucket outside, unlikely there was a light operated fan back then. I would say its entirely possible that one of the T&E's is for a fan, especially as there is an extra cable than normal there and the OP has infact said there is a fan in the room, so my guess would be that 3 reds go together, 3 neutrals go together and the other red whichever it may be goes in with the flagged black wire.

    If you put the 4 reds together and the fan runs constantly then you need to disconnect one red at a time until the fan stops, but the rest of the lights stay on.

    PS no matter how clever you think you are always note down what goes where, it just saves so much agro and hair puling later on in the day.
  14. Sparkielev

    Sparkielev Well-Known Member

    Reckon the OP has been sent to the sofa by his Mrs in the dark :)
  15. robertpstubbs

    robertpstubbs Active Member

    Another scenario is that at some point in time a fan was disconnected from the ceiling rose because because the original fan was dangerous or redundant, and since then somebody has reconnected the wires.

    In my experience the most likely reason for there being a 4th set of T+E from a bathroom ceiling rose is to supply a light switch operated fan.
  16. robertpstubbs

    robertpstubbs Active Member

    I've owned and managed properties built in 1970 so I know how electics were done then.
  17. Sparkielev

    Sparkielev Well-Known Member

    or a pull cord fan
  18. peter palmer

    peter palmer Well-Known Member

    I've owned a house built in the 1800s but I've never doffed my cap and put the gas lights out.
  19. peter palmer

    peter palmer Well-Known Member

    Without seeing it for myself it could be for anything, it may be a permanent feed for a fan with a built in pull cord, it could be a humdistat fan or a simple switched fan. or it could be for a loft light or security light and the fan is hacked into a bedroom socket the other side of the wall, who knows.
  20. DIYDave.

    DIYDave. Well-Known Member

    Or a tv Ariel booster

    Or a vanity unit light

    Or a shaver socket

    Or a fan

    Or a light in the loft

    Or a shower pump

    Or hydroponic kit for growing weed

    Or or or or or or or or etc

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