I have a light fitting to wire up in my kitchen. There is only one switch and has only been one fitting in the past, there still is now too. There are six wires sticking from the ceiling, three black and three red, and only one red and one black going through the switch. The problem is this... Of the six wires there is a constant 247v between one of the blacks and one of the reds, the others seem to serve no purpose. The current does not change when the switch is turned off and there doesn't appear to be any current at all going through the switch. When I took out the old light I think that only two wires were connected, but I can't be sure. All the fuses are intact and I'm stumped.

Can anyone fathom this witchcraft?

[Edited on 17/6/05 by Chris_R]

Interesting....you only need to connect the ones that switch when you throw the wall switch. No idea why there are 6 wires in there...there isnt 2 earths is there? That have been wrapped in insulating tape? The only reason there would be more than one pair of switched wires is if there is more than one wall switch to turn the same light on and off...

http://www.diydata.com/techniques/light_rose/ceiling_rose.htm

Oh of course, on some ring circuits the ceiling roses are used as junction boxes...so you can end up with loads of wires in them, and they can be a pain to work out!

David

[Edited on 17/6/05 by flak monkey]

haha.....red to black and blew to f**k springs to mind....

give me a call chris......numbers on the website...not gonna try draw pictures...

That's what I thought, that or two light fittings. I think that four of the six wires were isolated when I removed the old one, but like I said I cant be sure. whatever the reason, it's a bit of a bummer.

Right,

of the six wires you have sticking out of your ceiling (which will be 3 pairs of black+red?), one pair will be a live feed from your consumer unit (live and neutral), one pair will go to your switch, and the third pair will go to other light fittings.

What you need to do is find which pair go to the switch(using a tester ideally).

then at the ceiling the black wire which comes from switch needs to be marked with red tape, and should be connected to the live of your light fitting.

then connect the remaining 3 reds at the ceiling together using a 15amp connector block.

then connect your last 2 blacks at the ceiling together and to the nutral(probably blue)on your light fitting.

any earths(green/yellow) should be connected together.

HTH

Ray

[Edited on 17/6/05 by rayward]

nicely explained ray...

Ta Very Much!

I am not an electrian but the lights will be wired in a ring with the mains/common/earth supply looping in and out of each fitting. The 6 wires are probably as follows

Red

1. Live mains from previous light socket.
2. going to the switch.
3. Connetced to live from previous light sockett and going onto the next fitting.

Black

1. Common from previous light socket
2. coming back from the switch and into the light fitting.
3. Connecting to common from previous light socket and going onto the next one.

You could confirm this with your meter after turning the mains off.

Hope that helps.

Excellent stuff guys, thanks very much. How do I find out which ones go to the switch?

<EDIT>I have a multimeter and a sparkys screwdriver to work with.</EDIT>

[Edited on 17/6/05 by Chris_R]

it is a nightmare when you lose track of which wire is which! remember that only the live is switched, other neutrals will maybe just join up from other lights.

the switch must affect something, check the voltages between all wires (15 combinations) in both switch positions. If no pattern forms, rip it all out, smash the roof out, and rewire the entire house from scratch. And whilst you're at it, make sure you have an RCD in there somewhere!

remember that red and black means nothing, one will be a switched live and should have a coloured band round it, but they usually dont (sloppy twats).

[Edited on 17/6/05 by JoelP]

with the power OFF at fusebox.......

put multi meter on ohms or bleep setting...

turn switch on

put it between a red and black (of the same cable pair if you can see it.) ..if a pair beep turn switch off and recheck same pair - it shouldnt beep...

you may get beeps from other lights in house...if the beep doesnt go away when you switch off switch its the wrong ones..

you can do it with the power on, but Im not gonna tell you that unless your struggling

[Edited on 17/6/05 by colibriman]

Joel....your mad..

mad, bad and sad

You are best to do any tests with the mains off the ring you are working on. However you have identified the red wire that comes from the previous light fitting (in you previous post). You now have a 50-50 chance you will pick the the red wire going to the switch (check there are no mains voltages on them) then connect one leg of your meter to the red wire and look for a short across one of the blacks (with light swicth on) You should see a short when you connect to one of the black wires. Once you do confirm by swicthing light swicth off. You have now identfied the pair that goes to the light swicth. If you do not get a short try the other red.

Best of luck.

I concur 100% with Rayward. The lights are not on a ring but on a radial circuit which means that if you break it there will only be one pair of wires (red/black ) or (brown/blue in new colours) that are live. But AND BIG BUT beware not to seperate the black wires of a radial circuit when the reds are still connected, because if the power is still on or turned back on for metering purposesas and a light is turned on farther down the radial circuit the power will be coming back up the neutral which you have disconnected and as such can't find a return path. UNTIL YOU TOUCH IT Like i said beware I learned the hard way.

think its all sorted out now....

Just spent the last 15 minutes on the phone to Colin who's an absolute saint, massive thank you. Thanks to everyone else too, I can see in the dark now.

Sorry about the poor quality pic, took it on my phone.
Rescued attachment Image003.jpg

cool.....glad to be of help....

quote:

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Originally posted by omega 24 v6
the power will be coming back up the neutral which you have disconnected and as such can't find a return path. UNTIL YOU TOUCH IT Like i said beware I learned the hard way.

---

i know its done...already...

the only thing you needed to do...

is hook up all the live ones....and hook up all the blue ones..(from the light to it)

hook up all the yellow ones to..

then you stick with the switch output ones....

if you join all the red ones to gether..(its just live splitting)

then with some one at the switch..
find the right black one.. connect it to the light..

(so then search for an connection between black and red/brown..)

mark the others and you are done..

its an good thing that you have spare blacks...

with that you yhave spare leads..
some times with short circuits the cables brake in 2...etc..

Tks