Lights not working

[chudford]

My Daughter has a problem with the lights in her bathroom. It is a large house on four floors and there are 10 bulbs in the bathroom controlled by 4 seperate switches. None of the bathroom lights work but all the other lights on that floor work. There is not a seperate RCD for the bathroom. I suspect that a wire has come loose somewhere on the lighting circuit. Is there a way of finding where the loose wire is without taking all the ceiling roses off in turn. Thanks

[Toby]

I doubt it, but would start with the switches first, it might me wired by the main feed to the set of switches, that then go up to the lights, if there isn't any power here, then you need to work back form here.

It might be the neutral that has become disconnected, so if you test the live in the switch, against a neutral in the switch if there is one), you may not get anything, but this does not mean the live is not live - you need to measure between this live and earth, if there is one, I would also get measure between this same live, and the neutral from a known working socket (Via an extension lead, if necessary)

Can you take a picture of the back of the set of switches?

[TMC]

are these 240 volt lights or low voltage halogens?

If the latter could be a transformer gone

Tony

[chudford]

Thanks for the ideas. I hadn't thought about a transformer. The 4 switches are just 2 wires each to a single pole switch, so presumably just switch the live. I am going down on Sunday to try and fix the problem.

[robgraham]

If it is transformer driven, have a look at any connectors on the LV side as my lights kept on dropping out and I didn't realise for some time that the connector was seriously under specified for the current it was carrying and was potentially a fire source. Rob

[John]

Thanks for the ideas. I hadn't thought about a transformer. The 4 switches are just 2 wires each to a single pole switch, so presumably just switch the live. I am going down on Sunday to try and fix the problem.

Usually you do just switch the live on a lighting circuit - but bear in mind what others have said - you could have a break on the neutral. This could be linked to a ceiling rose in a nearby room. Have any fittings been changed?

You didn't answer the question about a transformer - are you able to confirm if the bulbs are mains or 12 volt?

[chudford]

Sorry I don't know at the moment as I haven't seen the problem, I've only been talking over the phone to my Daughter. I shall be going down to her house on Sunday to try and fix the problem.

[Dave Plowman (News)]

I'd say it's a bit unlikely given the four switches - it wouldn't make sense to switch at DC - and, what's more, removing a large part of the load might allow the volts to rise too far.

[Dave Plowman (News)]

I suppose you could make an educated guess by the layout of the house - but are you sure all the connections to that circuit are actually in the ceiling roses? In these days of low voltage stuff and fancy fittings they often aren't.

You could try a live cable finder - but I'm not sure how well they work.

[John]

If 12 volt then I wouldn't underestimate the impact of bulb failures. One can lead to others blowing - and so on.

Next - look for a fuse at the transformer - or a loose connection.

Whatever the voltage:

Assume the wiring was okay - then consider what might have been tampered with (new fittings, switches, etc)

Don't assume fault is on live (line) feed - consider neutral as well.

Take a camera - if you cannot understand what you are seeing - post a photo.

[thescullster]

"Toby" wrote

If you test between live on the lighting circuit and neutral on the power, won't you introduce an imbalance in the power circuit sufficient to drop out the RCD?

Phil