Light supply under voltage

[lavinpj1]

All of the lights on a circuit do not work. There is a live supply to the fittings but the voltage between live and neutral is only 200v.

The supply at the box is 240v on that circuit.

What might be the issue?

 

[ericmark]

Wait for BAS with his crystal ball. But likely somewhere line and neutral have got mixed up.

Likely some one working on the lights has not noted which wire was the switched line and has thought because it is black/blue it was a neutral then realised his error and guessed which was neutral and guessed wrong.

However I could also have guessed wrong?

 

[lavinpj1]

It was working a few days ago and no work has been done for a while. On further inspection, one of the light'a supply is at 0v. Again, it used to work

 

[AndyPRK]

a poor connection somewhere.

 

[ericmark]

Again a guess but likely some vibration walking has slackened off a terminal and a wire has fallen out or making a bad connection. With power off of course undo ceiling roses and gently pull each wire. Likely close to consumer unit if all lights are out.

 

[lavinpj1]

Thanks, no luck with that. I may have to get an electrician in but it looks to be a difficult job as the problem is probably under a floor

 

[ericmark]

It is very rare for a cable to become damaged it's normally where it's connected to something. Today all junction boxes must be accessible or a special maintenance free type. But years ago it was common to fit these

under floor boards. Often you can see where boards have been removed before so lifting carpets may show where to look.

But chances are the fault is not under floor boards and there is a simple cure. In the past where I could not get a 6A supply I have used a FCU to reduce maximum power have a look for a FCU and test any fuses found.