Halogen light fitting very dim

[enoughDIY]

Hi,

I've just replaced a light fitting with a 4 bulb halogen unit. With all four bulbs installed it is so dim you can see the filaments. It gets progressively brighter as you take the bulbs out. With just one in, it looks normal. I've double checked the wiring a number of times so I don't thinks it's wired up wrongly. Obviously something's not right. A check of the voltage of the bare connections at the fitting is 240v without the light fitted, but about 85V when it has all four bulbs in and it's on.

Can anyone help?

 

[TAB]

What wires are at the fitting and is the light supposed to come on with another light?

 

[enoughDIY]

It's not supposed to come on with another light. The wires at the fitting are three live wires wired together in a terminal block. Two neutral wires attached together and into the fitting. Two earth wires together into the fitting, and one switched neutral marked as live.

Can I have mixed up the neutrals? I'm presuming it wouldn't work at all if I had? It seems to work normally i.e. on and off with the switch, it is just very dim.

 

[TAB]

You are describing a typical light fitting (apart fom only two earth wires).
If you mixed up the black wires then you would blow the MCB when you operated the switch. Have any other fitting been swapped?

 

[enoughDIY]

I think you're close to the solution. I realised yesterday that the light output changes depending on the position of the switch for another light in the next room. I changed that fitting beforehand and lost the switched live wire. I refitted it and it seemed to work and no fuses were tripped, so I thought I had identified the correct wire.

However, I think now that I hadn't as I have the problem with the other fitting. I'll try and check the live on the first fitting and see if that solves the problem. I've got hold of instructions to identify the switched live with a multimeter.