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Electric light re-wiring

Hi can anyone help, trying to fit a new ceiling light. I took down the old fitting and have 4 wires. 1 black wire, 2 black wires together, 3 red wires together and an earth wire. The new light fitting has the L N E. I have fitted the new light using a terminal, the light comes on but will not switch off. I have matched the 3 red live wires to the brown live wire in the terminal. i have matched the 2 black neutral wires to the blue neutral cable. earth to earth. this leaves the single black neutral wire in the terminal with no cable the other side. My question really is why won't it switch off?

7 Answers from MyBuilder Electricians

Best Answer

Hi daveb 22
This is a common error made by a lot of diyers , the following info should help you as you don't need to be part p registered to replace a light fitting.
Firstly your lighting circuit should be turned off then connect as follows.
The three red cores should be put together into a piece of connection block and not with the brown of the light as you have done,these reds are the permanent lives for the circuit hence why the light stays on.
The single black wire is the wire that returns from the light switch and should have a small piece of red tape on it to denote it becomes live when the light switch is turned on this wire goes into the brown of the light fitting.
The two blacks do indeed go to the blue of the light as they are neutrals.
And the earths go to the earth of the light fiting.
Hope this helps.
paul

2015-04-19T12:05:02+01:00

Answered 19th Apr 2015

1x black wire-live terminal
2x black wires-neutral terminal
earth-earth
3x red wires-free terminal

Ideally circuit should be insulation/ELI tested using test equipment by a competent person.

2015-04-19T12:05:02+01:00

Answered 19th Apr 2015

Because the wiring is twin and earth, the return wire coming back from the switch will be a black one. Put the 3 reds together into a connector block. The 2 blacks connect to the blue. The single black will be the return from the switch, that needs to go with the brown wire. If the light is a metal one then the earth wires will go into the earth terminal.
If in doubt, get a properly qualified electrician to fit it.

2015-04-19T12:05:02+01:00

Answered 19th Apr 2015

It sounds like you have some cables crossed. At a guess i would say the single black cable is your live wire. The 3 reds will be your live loop and the 2 black wires will be your neutral conductors. However i would highly recommend getting someone who is competent to just check it before switching it on

2015-04-19T12:05:01+01:00

Answered 19th Apr 2015

don't put any wires from the light fixture to the reds put the brown cable to the black cable on its own as its the switch live and put brown tape on it and the light would work

2015-04-19T12:05:02+01:00

Answered 19th Apr 2015

My immediate response is to get a qualified electrician in as you're one step away from blowing the fuse/circuit breaker or killing yourself.

The wire you're calling "the single black neutral wire" is actually the live coming back from the switch. Good practice is to add sleeving (red in the old days, brown these days) over the conductor to indicate that the conductor is actually live rather than what might be suggested by the colour of the insulation. Often times, electricians omit to use sleeving. A competent electrician would know this.

What you have done is to connect the switch feed, loop in & loop out live conductors directly to the lamp so it's permanently on, leaving the "the single black neutral wire" (your switch wire) goodness knows where - hopefully connected securely away from other neutral & earth conductors. Those 3 live conductors should NOT be connected to the lamp at all, but are using a common connection point to take a conductor to the switch. It is "the single black neutral wire" that needs to be connected to the live (brown) side of the lamp.

However, everything I've said here could be wrong, and only testing the conductors with appropriate test equipment on a dead circuit can verify what conductor has actually been used for what purpose.

Do yourself a favour & stay alive.

Oh, and get a qualified electrician to do the job: it'll take them 15-20 mins.

2015-04-19T12:05:02+01:00

Answered 19th Apr 2015

You should wire the brown wire to the single black wire( which is the switched live) and the blue wire to the two black wires ( neutral ) and earth to earth.

Regards

Martin

2015-04-19T12:05:01+01:00

Answered 19th Apr 2015

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