Changing a light fitting

Linford

Probably a very novice question, but here goes:

I want to change the ceiling lights in two of the rooms in my house and I assumed I could do it myself, but when I was removing the light fittings all of three of the wires going into the fitting are the same colour (grey) and there is no indication on the old light fitting which wire is neutral, which is live and which is the earth, two wires go into one of the holes and the other wire goes into a hole on its own. My new light fittings give specific instructions which wire goes where but also states that each wire is a different colour (as does my DIY book), there is no further instructions than that.

I know I can test which is the live wire by using a faze tester but I am I right in thinking that the earth is the wire that is on its own and that the neutral wire is the one with the live wire. Or am I totally wrong and should seek the services of an electrician?

Hoagy

The standard method of wiring lights when using single cables is to loop the neutral from light point to light point, so that would explain the two wires going into one terminal. They must remain joined otherwise another light further along the line will stop working.
The single wire on its own is the live coming from the switch.
There probably isn't an earth wire.
Earth wires at ceiling lights have only been a requirement since the 1991 Wiring Rules. I'd guess your house was wired prior to that.

Linford

Thanks for that - my house was built well before 1991. There is an earth fitting on the new light fittings I have, is it ok to install the light without there being an earth wire in place? Also is it dangerous not to have my house earthed?

Hoagy

The safest advice would be not to install a light fitting which needs an earth, however it has been done many times, it's really up to yourself.
Not having earths in the lighting circuits is not dangerous unless you start adding metal light switches or fittings.
THe cost of putting earth wires in at this stage would be prohibitive.

JohnDigital

Earths in lighting circuits are a recent phenomenon. Don't worry about putting a light fitting that has place for an earth up, if your house light circuits are not earthed there is nothing you can do.

If you look closely you will see that under the grey covering on the cable there is a coloured inner sleeve. given that your house is not new it is probably red and black rather than the now usual brown and blue.

In all cases the Red or Brown is the positive and the Black or Blue is the negative, just wire the light fitting accordingly.

You will probably find that your lights have more than just two cables running to them, this is because a few lights are looped along the same circuit, just ensure that all the wires are connected up the same way in the new light fitting as the old one.

If you are tight for space with the length of cables in the ceiling or space in the connector on the new light you can extend the wires using a terminal block and some short lengths of cable to make wiring the new light fitting easier. Just push the terminal block and new wiring into the ceiling when fitting the new light fitting. Be careful when you are adding fixings for your new light fitting that you don't trap or put screws through the wires.

If you don't have testing equipment switch off the power at the main breaker on your fuse box, don't just rely on the labelling of your fuse box to be correct. Much of the wiring in older houses leaves quite a lot to be desired, particularly if the house has had work done on it in the past, so it is better to be safe than sorry.

hughm

My house is frpom the 50's. I have changed all the lights but had the same issue. 3 grey wires all in 1 connection. I just made sure that I kept the wires that I took out of the old unit together so as not to screw up. kept them together with elec tape before i removed them from the old unit so i woudl remember which ones needed to stay together.

Had similar issues with replacing light switches.

Linford

Thanks for all the advice.