Any electricians here?

Discussion in 'OT (OFF Topic) Forums' started by Greenmanslk, Nov 2, 2018.

  1. Greenmanslk

    Greenmanslk Hardcore MB Enthusiast

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    I have just had a loft lnstalled, which was wired into an existing ceiling light; since the installation, the ceiling light occasionally flickers when on.

    Ive just checked the switch on the new loft light and discovered it swtitched across the brown lead - is this correct?

    The wire into the existing ceiling light is secure so im struggling to fund the cause of the occasional flickering...
     
  2. richard

    richard Authorised Forum Sponsor Authorised Forum Sponsor

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    I am not an electrician and I would advise you to leave the wiring alone and get an electrician, as without experience avoiding electricity is good. Especially so as lighting may not be covered by a RCD and you can never be sure someone didn't do something crazy when odd things are happening and the wires coming from switches go live when the switch is on. They will have proper safety screwdrivers and tested ..

    Current wiring standards for single phase are Brown is Live, Blue is Neutral, Green/Yellow is Earth. If you find Black and Grey in your wiring that can also be live in new wiring where you have more than single phase which happens in big houses and industrial premises and you find it where you have two way switches and fans in toilets (and probably in all kinds of other places). And of course a Blue wire can become live if used for wiring in a switch (and should be marked with a brown marker, but that get missed out)

    Old wiring colours are different and we certainly have both colour schemes in our house as things have been extended over years. (Red = Live, Black = Neutral). Note therefore that when you have a mix Black can be confusing as it is Live in new wiring and Neutral on old wiring.

    Have you just tried changing the bulb in the flickering light ?

    Cheers

    Richard
     
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  3. flowrider99

    flowrider99 Hardcore MB Enthusiast

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    Black is live in old wiring, brown is live in new wiring as you stated earlier. There is no black in new wiring.
     
  4. richard

    richard Authorised Forum Sponsor Authorised Forum Sponsor

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    David,

    Black is live in 3-phase new wiring. Brown is L1, Black is L2, Grey is L3. L2 & L3 were Yellow and Blue in old wiring (and of course Blue is Neutral in new wiring). Thats one of the reasons installations with both should have great big warning stickers telling you both colours exist in the fusebox.

    Also, when you get multicore wiring with more than 2+1 (i.e used for 2 way switching and sometimes bathroom fans, the extra wires become black and grey, and can become live when the switch is on. In theory these should have a brown sleeve put on at the ends, but if you are in the middle of the wire you can't see it, and I threw an electrician off site (my house, some years ago) for not putting the brown sleeves on switch wires (and not really understanding how to wire up two way switches)

    Richard
     
  5. richard

    richard Authorised Forum Sponsor Authorised Forum Sponsor

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  6. whitenemesis

    whitenemesis MB Club Veteran

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    Flickering must surely be due to a loose/poor connection? Have you checked the wiring in the old ceiling light rose?
    Suggest, strongly, you isolate the circuit before exploring, turn the light on and flip the circuit breaker in the consumer unit and confirm the light goes out..
    P.S. I'd also change the bulb, just to rule that out...
     
    Last edited: Nov 2, 2018
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  7. flowrider99

    flowrider99 Hardcore MB Enthusiast

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    Sorry Richard, I thought you were talking about single phase wiring as 3 phase is not normal in a domestic building.
     
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  8. m80

    m80 Hardcore MB Enthusiast

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    Check the switch is making good contact, often plaster dust gets between the contact points. To 'possibly' prove this manipulating the switch when the light is flickering may give good indicatation. A new switch is cheap enough.

    Be careful with some of the above info it could be misleading.
     
  9. CJD

    CJD Active Member

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    I would think that one of the conductors is not securely tightened in the rose or connector block.
    Obviously you should isolate the correct lighting circuit at your consumer unit before investigating.
     
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  10. renault12ts

    renault12ts MB Club Veteran

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    Careful, red is for danger...ie it is live. Black is NEUTRAL...for single phase.
     
    Last edited: Nov 2, 2018
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  11. renault12ts

    renault12ts MB Club Veteran

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    OK stop.

    We are mixing three phase and single phase and as a result the OP will be very confused. If naming the colours mention the phase.

    In single phase normal UK house wiring black and blue are neutral, red and brown are live. Anything with green is earth.
     
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  12. Meldrew2

    Meldrew2 Hardcore MB Enthusiast

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    Flickering is caused by a loose connection. Loose connections will run hot.

    Suggest that you have a qualified electrician check things out as a priority as in an extreme case a fire could result.
     
  13. zipdip

    zipdip Hardcore MB Enthusiast

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    Well just what wires are doing what does not matter too much you quiet often find a black/blue wire that is live,I would suggest you have a wire in that particular light that is not tight,I see you have checked this,so make certain the connections at the switch are tight,if they are then change the lamp/bulb itself for a new one,if it still flickers then change the holder if possible,if that does not stop the flicker then change the light switch or get a electrician around who will put his meter on the system and tell you if you have a dodgy neutral and where it is.
     
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  14. OP
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    Greenmanslk

    Greenmanslk Hardcore MB Enthusiast

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    Thanks everyone

    Im always wary of electrics as you cant see it, smell it or touch it...without it hurting...
     
  15. bob6600

    bob6600 Hardcore MB Enthusiast

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    I would ask whoever installed it to come and have a look if it was done recently which seems to be the case from your post
     
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  16. OP
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    Greenmanslk

    Greenmanslk Hardcore MB Enthusiast

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    I should add that the landing ceiling light only flickers when we use the downstairs switch....using the upstairs switch does not cause any problems

    So im thinking the problem is with thr downstairs switch which is 3 way in that it has separate swiches for outside, hall and landing.

    I will switch everything off tomorrow and check for any loose wires..

    Thanks again for all the comments and suggestions...
     
  17. renault12ts

    renault12ts MB Club Veteran

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    You may be able to smell it...loose live wires cause sparking etc.
     
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  18. Petrol Pete

    Petrol Pete Hardcore MB Enthusiast

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  19. Petrol Pete

    Petrol Pete Hardcore MB Enthusiast

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    One of the wires in a single pole switch is always live , when you close the switch it completes the circuit and the lamp magically comes on.
    Old wiring will sometimes have a black wire with a little bit of red sleeving over it to indicate that it's permanently live. As explained above the colours have changed.

    My house has both old and new wiring and a notice on the new consumer unit states that. Its a legal requirement. The new part of your wiring must have a certificate from the installer.

    I had a new bathroom fitted and went from one light to 10 also with under floor heating added. The spark wanted to fit a small DB outside the bathroom to cover 'his bit' of the house wiring. I instead asked him to fit a new consumer unit (not very expensive especially if you have an old unit that needs upgrading) That way he has to test and certify the whole house, useful for insurance and sale purposes.

    I am qualified as an electrician but I don't' do 'house bashing'..in fact I don't do any sparking these days, too much like hard work :rolleyes:
     
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  20. OP
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    Greenmanslk

    Greenmanslk Hardcore MB Enthusiast

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    Thanks everyone

    I traced it to a poorly connected earth in the ceiling rose on the landing - particularly frustrating as that light had been fitted by a qualifed electrian, who had fixed a few other issues (immersion heater on a 3 pin plug!) as well as issueing a new certificste. We werent convo ced the last one was completely legit. We only bought the house in May.

    All seems ok now ....although i do miss the flickering light....
     
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