Bathroom Lights tripping

point3

I have low-voltage downlighters, in an ensuite bathroom, which trip the lighting circuit every time they are switched on. :mad:

I think it's the downlighter over the shower cubicle itself that is the main culprit, but does anyone have any ideas as to what the specific problem might be ... or do I need to call in an electrician?

The house itself is newbuild and the original owners did have the builders in to check the electrics a few times, but the fixes they came up with all appear to have been temporary. We can get away with not having lighting in this room, as there is a large sunny window - but what could the problem be?

silvercar

low voltage downlighters occcasionally start to overheat and melt damaging the wiring. Take the light bulb out and have a look at the wires, you will see if there is a problem straight away.

point3

Thanks for the reply, silvercar.

I checked the bulb and that looks fine (50 Watt GU10). I checked the transformers in the attic and I think you may be right about the overheating...

The transformer over the shower is different to all the others - it is a different make and lower rating (IBL dimmable transformer 20-60W) and there appeared to be scorching :eek: of the loft insulation surrounding it. The wires themselves look OK (clear sleeve), but there is a cut earth wire sticking out of it. The other transformers don't have earth wires so I'm presuming this isn't a problem.

So...do I change the transformer or just try a lower wattage bulb in the fitment? Or is there another solution?

Any thoughts appreciated.

kat21

Make sure that the fitting is made for a bathroom as you can get low voltage downlighters where some are and some are not. So, the first most important thing is to make sure its for a bathroom do a search for bathroom low voltage downlighters. If it is the correct type then you need to change the transformer they do go after a while. as with all things electrical make sure you turn off the mains lighting to the area you are working on and if in doubt contact a qualified electrician.
I doubt changing the light bulb for a lower wattage would solve the problem. look for a bathroom downlighter and transformer replacement.have a look here http://www.lighting-direct.co.uk/bathroom.asp and then at their bathroom downlighters
Zone 0 is inside the bath or shower itself. Any fitting used in this zone must be low voltage, (max 12v) and be rated at least IP67 which is total immersion proof.
Zone 1 is the area above the bath to a height of 2.25m from the floor. In this zone a minimum rating of IP44 is required. If the fitting is 240v a 30ma residual current device (RCD) must also be used to protect the circuit in this zone.
Zone 2 is an area stretching 0.6m outside the perimeter of the bath and to a height of 2.25m from the floor. In this zone an IP rating of at least IP44 is required. In addition it is good practice to consider the area around a wash basin, within a 60cm radius of any tap to be
considered as zone 2.
Zone 3 is anywhere outside zones 0,1 and 2 (subject to specific limits) and where no water jet is likely to be used. No IP rating is required. In addition to the above, if there is a likelihood of water jets being used for cleaning purpose in zones 1,2 and 3 a fitting rated a minimum IP65 must be used.
Full details can be found in the latest copy of the IEE wiring regulations
kat21

point3

Cor! Thanks for the comprehensive reply.

Right then, I need fittings for bathroom Zone 1 (above a shower basin) so that's at least IP44?

I think the ones in-situ at present are standard IP20 fittings so it looks like I will need to go shopping for a new downlighter and transformer!

There will be light at the end of tunnel *bad joke - sorry*

YorkshireBoy

point3 wrote:

...I will need to go shopping for a new downlighter and transformer!

...and when you fit them, remove the loft insulation from around both the transformer(s) and lamp casing(s).

Sit the transformer on a piece of heat resistant board straggling two joists/trusses, ensuring adequate air flow around it.