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Message started by chopster on Sep 27th, 2004, 9:33am

Title: How many????
Post by chopster on Sep 27th, 2004, 9:33am

Hi, I'm new here and fairly new to diy electrics, however I am reasonably competent and I tend to ask 300 questions or read a lot before I actually start anything.

I now fully understand why there may be one, two or three 3core cables coming into a light fitting, and have changed some at home already......... but the other day I took my daughters bedoom light down (it's an old green 3 lamp spotlight on a single plate, and it scares her)wanted to put up a single pendant with shade..... when I opened it up, there were 4 cables coming in and they were wired all over the shop.

I can't go up in the loft to sort it out yet as we have a wasps nest and I'm waiting for them to die.

Can anyone tell me why there might be 4 cables coming in (is it possible the moron who lived there before has spurred off to the loft light or something..... is that actually possible to do?)

I know it's probably a stupid question for the experts, but be nice, please..

Thanks

(ps, I'm based in the UK if that makes a difference)

Title: Re: How many????
Post by plugwash on Sep 27th, 2004, 10:19am

there are two main possibilitys for a light fitting with four cables

one is that one cable is a spur (so you have three cables connected to the same place rather than two)

the other is that one cable is a run to another light on the same switch taken from the terminals that go to the fitting itself


Title: Re: How many????
Post by chopster on Sep 27th, 2004, 10:29am

Thanks plugwash, hadn't thought of the 2nd light on same switch one (mainly because there isn't one in the room), but it wouldn' surprise me in the slightest if there used to be one, and that wire is now just going off to nowhere. I think there is actually a pull switch in the wardrobe that does nothing

(anyone seen the money pit!!!!!!!!!!)

Is there any simple ways to test the wires and find out what is what?


Title: Re: How many????
Post by L.Spark on Sep 27th, 2004, 6:10pm

Be carefull Chopster as getting a shock is easy to do, without a voltage indicating device, which just tells you if its live or not, It's not very easy to test or work out wihtout one of these.

If you havent already fixed it I suggest you find out how many terminals are in this light fittings and what cables go to which terminal, including what colours the cables are, then we might be able to help you more.

It's usual in a bedroom to have cables going in and out, one of these would be a 'supply in' and one would be a 'supply out' to the next light fitting say in the next room, you would also have a cable going to the light switch most likely.

As I say, more information needed really.

Title: Re: How many????
Post by The_Trician on Sep 27th, 2004, 7:02pm

1.Live 'in'
2.Live 'out' to next fitting
3.Switchwire 'in'
4.Neutral 'in'
5.Neutral 'out' to next fitting

OOH - That's 5!

And don't forget the earths!

TT

Title: Re: How many????
Post by chopster on Sep 28th, 2004, 9:05am


wrote on Sep 27th, 2004, 7:02pm:
1.Live 'in'
2.Live 'out' to next fitting
3.Switchwire 'in'
4.Neutral 'in'
5.Neutral 'out' to next fitting

OOH - That's 5!

And don't forget the earths!

TT


It's 4 t&e, hence 4 earth 4 live and 4 neutral, and some of them seemed to be wired straight to each other via seperate connector blocks. I can't remember the setup but will try and look and come back to you.



Title: Re: How many????
Post by L.Spark on Sep 28th, 2004, 2:44pm

Hey Chopster

Well 4 T+E sounds more like it, 4 cables made me think 4 core's

well most likely one of them is a feed, one of them will be to the switch, one will be to the next light in the room, and one will be to the next room in the house

like

FUSE -> LIGHT -> Next Light ( Same Room)
            |                     -> Next Room ( e.g next bedroom)
            V
            SWITCH

Title: Re: How many????
Post by supra59 on Sep 28th, 2004, 11:44pm

hi chopster

just be careful because you said,  i qoute there are four live, four earth, and four neutrals,

one of your 4 T&E cables should be dbl red and earth which is the switch wires, but from what you have said theres is a stong possibility that one of the black single cables will be live as some sparks use red and black for the switch wires and should use red tape to mark the black cable, but some dont bother putting the red tape on. when you have another look you will proberly find 1 black cable is connected with the reds make sure you mark the cable with red tape and dont connect it  to the black neutrals as this will cause a dead short.

so in short you should have 4 earth 5 live one being the switch wire and three neutrals hope this makes sence.

Title: Re: How many????
Post by L.Spark on Sep 29th, 2004, 2:17pm

yep thats the way it should be, btw we use sleeving these days  8)

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