Bathroom Lights Problem, please help!

Hiya,

I have a problem with my bathroom lights, we have spot/downlights like these in the bathroom ceiling:



They are going from 12V into the mains via a transformer. Around Christmas all the lights didn't come on anymore so we bought a new transformer as we thought the old one was broken, after exchanging the transformer the lights worked for about 1/2 hour and then the new transformer blew as well! We have measured the voltage on the mains and it's about 300V (is that too much?), the cables are all up in the loft (is it too cold for the transformer as it first blew in winter, we haven't tried to fix it since?). Any idea why the transformers keep blowing and what I can do about it? Any help is very much appreciated!

How did you measure your mains voltage? Was it with a calibrated voltage meter? The max allwable supply voltage in the UK is 253V RMS
Nominal voltage 230V. High voltages will kill the transformer. They do not mind a bit of cold, they will fry if they get too hot.

it could, simply, be a loose connection somewhere.

As lighting in bathrooms is notifiable, why dont you as the electrician who installed them to come and sort it?

Have replaced any bulbs in there with higher wattage than the original ones?

FourFootMedia said:

Have replaced any bulbs in there with higher wattage than the original ones?

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need more info lamp rating transformer rating number of lights possible you could have overloaded the transformer

Incorrect use of a multimeter may record higher values than the RMS (Root Mean Square) value normally quoted as the mains voltage.
Switch mode power supplies may give similar high readings on their output, especially if the output isn't loaded.

Is your replacement transformer the same power rating (wattage) as the original?

Hi guys,

thanks for all your replies, very much appreciated!!!

I'll measure the voltage again at the weekend with a proper volt meter, something is not right there, we only have a cheap one.

Well I don't know who installed the lights as we only moved in the house about 9 months ago and they were already in there. They were woking fine for 4 months. The lights switch (cord one) started to get a bit stuck after a while so sometimes you had to pull it twice to switch the light on/off, could that have something to do with it? Also when we installed the new transformer, the lights came on with about 1-2 seconds delay when you switched them on.

There are 10 lights in the bathroom, I think they are 10W - 12V Halogen Starlight Downlights, I can't remember what it says on the transformer as it's on the loft but I am sure we got the right replacement, we need at least a 100W right ? We didn't have to replace any bulbs as they were all working fine.

Thanks again for all your help!!!