Recurring issue with bathroom light.

Biker Joe · Dec 3, 2020

Hi all. I'm not an electrician and have very little experience so please bear with me. I have a recurring issue with my bathroom light. A while ago it stopped working and assuming it was the bulb I replaced it but no new bulb worked. The pull switch wiring looked intact and clean but on a hunch I cleaned the terminals on the lamp holder, as the bathroom does regularly fill up with steam and then talcum (yes I did isolate the lighting circuit beforehand) and this did the trick...for a few months. Then it started to fail again - the symptoms being that if I did a short pull on the switch it would just flash weakly and go out but if I did a long pull on the switch it would usually stay on. Now it doesn't go on at all, however long the pull is. So I want to ask whether this sounds like dirty/corroded terminals in the lamp holder again or something more serious going on? Thanks in advance.

Dartlec · Dec 3, 2020

Corroded or poorly connecting terminals could certainly be one cause, though pull cord switches often fail in similar ways too.

What sort of light is it in the bathroom? A standard pendant fitting? If so then it may not be the best suited for a bathroom, as steam can definitely cause problems with terminals corrodiing.

If you remove the lamp(bulb) during the day and look you should be able to see if the terminals are showing any sign of corrosion. But if you can't tell whether the light is on or off be sure to isolate at the consumer unit before you touch anything.

If it's within the zones (within 600mm of the side of the bath or shower usually), then an IP rated light fitting is a requirement (though it's common to find pendant fittings even in fairly new houses).

You can get LED ones now that are not that expensive and will never be affected by steam/moisture.

If you're at all unsure, it would be a simple job for an electrician to swap over light and/or switch - and shouldn't take more than an hour (assuming nothing odd is going on).

Otherwise the only way to tell whether it's the lamp connection, the switch, or the wiring would be to use a voltage tester and by the time you buy a suitable one you may well be worth an hours of a local electrician's time.

You could undo the pull cord and lower it just to see if any wires are loose - and the same with the light fitting (isolating first).

There are other alternatives, like a loose connection in the switch or at the light fitting, rodent damage to cables etc - though you would probably have noticed issues elsewhere if that was the case.

Biker Joe · Dec 4, 2020

Thanks Dartlec, some good points to ponder there. It's a straight batten lamp holder (similar to a pendant but attached directly to the ceiling without the dangly bit) with a halogen bulb fitted. The bathroom is VERY small so I expect it's all in the zone. The pull cord wiring looks fine but I'll check the light fitting wiring too while I'm at it. I'll look for corrosion on the terminals first then but might actually look into those LED fittings you mentioned. Do you mean there are IP rated LED light fittings similar to a batten or pendant or are they a totally different kind of thing? Thanks again for your help.

Dartlec · Dec 4, 2020

The traditional bathroom light was this sort of thing:

which takes a bulb (lamp) - which could be an LED one now of course.

Though they are commonly replaced with something like this now:

Which has a built in LED chip so is a complete fitting.

If your fitting is the bayonet type then it could well be corrosion. If it's the screw type, then the sprung middle terminal often needs bending back down slightly to make a good connection.

However, you probably want a fitting that is IP44 or greater to be suitable for a small bathroom - though it it's actually over the bath then you may need a higher rating as that is zone 1 - if the ceiling light is higher than 2.25m you don't technically need IP rated at all - but I've found that steam generally doesn't read the rules and stop exactly at 2.25m!

If there is a lot of steam/moisture it might be worth looking at whether the extraction is appropriate too, to avoid issues further down the line.

Biker Joe · Dec 4, 2020

That's great, very helpful info. Yes it's a bayonet fitting with the two push-in terminals. I'll take a good look at the weekend when I'm home in the daylight but I'm leaning towards getting a new LED fitting now (like the one in your second picture) and also leaning towards getting a qualified electrician to fit it - just to be on the safe side. Thanks again for your time and advice. I greatly appreciate your patience in helping a novice.