Wiring in ceiling light, old wires, 2 black 1 red Ask questions and find answers to many subjects relating to electrics and electrical work

[robmanmanc]

Hi all,

First post so apologies if this has been asked before.

I have just finished renovating my 1970's bathoom.

When changing the ancient light fitting I noticed that there were 2 black wires and 1 red wire.

I replaced the old fitting with a new 3 halogen bulb fitting from Ikea. The wiring required Neutral, Earth and Life.

Old old fitting had 1 black wire going into it and the red wire. Assuming these are Live (red) and Neutral (black) I wired them in and it worked fine. However I am left with this spare black wire as it was left before.

Just a little worried about it, wondered if I should wire it in as the earth? But there is nothing to differenciate between the 2 black wires apart from using the one that was wired in before.

It all works fine and no electrical problems anywhere else (apart from the light in the room next door seem to randomly stop working for 10 minutes the day after I fitted it - not sure if that's related or not)

Sorry if I've rambled on. Thanks

[daveb99]

Hey,if the cable is twin and earth sometimes the black core in the cable is used as the switch wire but if you said the light is switching on and off okay then thats not the case.Did u say the black core u mentioned was connected before?

[robmanmanc]

No it didn't seem to be or if it was it was very loosely connected in a came out when I removed the old connection. Im inclined to say it wasn't connecting.

A friend seemed to think that in old houses they sometimes had a looped neutral system so both of these black cables should connected to the neutral hole and there is no earth.

Light works fine, I was just curious as I like to understand these things

[robmanmanc]

The ceiling light in the adjoining room seems to be permanently out of action now. I'm starting to think this looped neutral thing might be correct and the disconnect 'spare' black should be wired in to provide a neutral for the light in the adjoining room?