help installing spotlights, they are stuck on!! can't switch

Postby marcguy » Thu Mar 15, 2007 4:17 pm

hi there, I have a problem putting spotlights in, basically from the ceiling there are 3 cables, with a live, neutral and earth in each, in 2 of the cables the earth is joined up into one cable so I guess these 2 cables came from the socket where there are 2 switches as the room has 2 lights.

anyway, no matter what combo I try, I either get the spolights on but unable to turn them off, or I get the spotlight off and can't turn them on but I can turn the other light on which I haven't touched yet (if I do get the spotlights on, then I can't get the other light on)

anyone with any diagrams or helpful ideas would be appreciated, it should be simple or so I thought!!

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Postby thedoctor » Fri Mar 16, 2007 2:21 pm

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Postby kbrownie » Sat Mar 17, 2007 10:14 am

A few questions
1) is this a new wiring circuit or an old one where you are replacing old fittings.
2) has it worked in the past
3) do both switches turn both lights on/off
4) are the swicthes wired correctly
5) are the two lights separate or on the same fitting

If i'm right in thinking you've got your An earth Green/Yellow, a neutral Blue maybe black and live/phase Brown maybe red and only these 3 cables, not 2 of each?
If both spot lights are seperate fittings is this true of both. how are the switches wired?
I'm trying to vidualise your problem!
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Postby Mal » Sat Mar 17, 2007 3:29 pm

What you are likely to be dealing with when you have three separate wires is standard 'loop-in' wiring. One of the wires will be coming from the consumer box and will be live (all the time), another wire will be taking that power along to the next light or junction box, the third wire will be the one that goes to the switch. To identify the 'switch' wire. turn the switch on and check for a circuit between the red and black wires. You should put a bit of red tape on the black wire to show that it's live. It will be easier to use a junction box to route the wiring, giving you a single wire into your light with switched power to the live terminal on the light(the black wire with the red tape) and the main neutral feeding the other side.

[size=18][b]Go to the projects pages on Diydoctor to look at the electrical projects. There are diagrams of lighting circuits and how switches are wired[/b][/size]
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Postby Mal » Sat Mar 17, 2007 4:58 pm

You've got a standard 'loop in' wiring system. One cable is the live from the consumer unit. One is the wire to the next light/junction box in the circuit and the other one is the switch wire. This type of wiring is usually associated with a ceiling pendant light with three separate terminal blocks and an earth block.
See ... itches.htm
You need a 4 terminal junction box to duplicate this.
First you identify the switch wire by turning on the switch and checking for a circuit between the red and black wires with a multimeter. Tag the black wire with a red bit of insulating tape to remind anyone that it is potentially live. Then wire up to the junction box to duplicate the pattern on the picture on the page above. i.e. a common earth, a common neutral, a fixed live (which has the all the red wires from the ceiling cables attached to it) and a switched live (which has the tagged black wire and your light's brown wire attached to it)
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Postby marcguy » Sat Mar 17, 2007 6:07 pm

thanks for the help, they are both working fine now.
the only thing one set of spotlights won't do is dim but I'm not too bothered about that, one of the black wires was the live switch so I put that into live and the 3 red cables into the loop terminal, other 2 blacks in neutral and 3 earths into earth, thanks.
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