Electrician advice please

JMSE

After about 8 years of looking at wires hanging out of the wall on both sides of the fireplace I've finally got round to buying 2 wall lights. Anyway at both places, theres 3 cables hanging out. At the first alcove theres 2 single brown core and earth cables, and 1 single core (blue). One of the browns is live when the switch is on.

Thats fine but which of the others is earth and is the blue the negative. I know this is a hard one and my multimeter is broken, is there a way to figure this out MacGyver style???

Davy

Im not sure i understand the question,,,?

The green is the earth, and the blue is the neutral. One brown is the feed, and the other is looping to feed the second light.

JMSE

No theres no obvious green earth, just 2 brown singlecore + E cables and 1 blue single core cable.

So one brown is live, the 2nd brown loops to the 2nd light and the blue is the neutral, but at the 2nd light, theres also .... 3 cables.

JMSE

Ok the 3 cables at the 2nd alcove are 1 brown single core +E cable and 2 blue single core cables. None are live when switch is on.

Davy

JMSE wrote: »

No theres no obvious green earth, just 2 brown singlecore + E cables and 1 blue single core cable.

So one brown is live, the 2nd brown loops to the 2nd light and the blue is the neutral, but at the 2nd light, theres also .... 3 cables.

So you have a twin brown and earth cable and a neutral (blue) cable. The earth is the bare copper between the browns.

If its a twin brown, then it would be wired different that what i said earlier. They may not have had singles, so used the twin, both twins might be back at the switch, you could open as see. No need to use both brown cores, just one for each light.

JMSE wrote: »

Ok the 3 cables at the 2nd alcove are 1 brown single core +E cable and 2 blue single core cables. None are live when switch is on.

You need to find the other end of the brown,

JMSE

Davy, theres no twin brown cable, theres 2 separate brown cables, both have earth wires with them, then theres 1 blue.

Yeah one brown is switch-live, then when I join it to the 2nd brown I get live feed at the 2nd alcove brown. Now my phase tester is showin 'some' power at the blues when I have the browns all live, but none when the browns arent joined. I dont get that. I dont get why theres 2 blues at the 2nd light.

The live comes from a dimmer switch if that has a bearing on anything.

Davy

The two blues at the light is one in, and the second is going to the other light

JMSE

I think I get whats goin on at the first light, and then at the 2nd I have a brown feed and 2 blues, 1 blue is linked to neutral via any nearby neutral point and the 2nd blue loops back to light no.1

Is that right?

I still dont get how the phase tester shows up a bit of weak power coming out of 1 blue at both sides. Theres no blue back at the switch, only browns and earths.

Hank_Jones

Just fit the lights, you just have a switching wire coming from the switch to the first light and then looped on to the others.

Neutrals generally aren't brought to light switches as they are not needed there, they are usually just brought directly from the board and then looped wherever they are needed in that circuit, ie to the lights.

Circuits are usually wired so that there is an end of line, meaning that it finishes with one brown or blue or earth at a certain place, that is why you have one blue at one light and one brown at another.

Make sure that you switch the power for the circuit off at the fuse board before you fit any lights.



*Qualified Electrician*