Transformer problems with Low Voltage Lighting

[DonnyO]

Help please....

I have 8 low voltage lights set into in my kitchen ceiling. All worked fine for 12 months but now one particular position keeps 'blowing' transformers. They last for a couple of weeks then fail. The problem is on one light only. Wiring is the same for all. The transformers are all in the ceiling voids and not subject to excessive heat although there is an airflow between the joists. There is no sign of the transformers burning out.

Any ideas?

Thanks,

 

[passerv]

Just clarify.

you keep blowing transformers,
But there is no sign of the transformer burning out

 

[Click-Sure]

 

[passerv]

Sorry thats me , you said low voltage lighting,strickly speaking you are referring to mains voltage, (IE 230V). Did you actually mean ELV. As you mention transformers I assume you mean ELV and as click-sure states we need more info.

So to coin a phrase: The balls in your court...

 

[DonnyO]

More info.

Its a standard 240 mains to 12 v transformer running 12v 35w halogen lights. Normal loop-in wiring arrangement. The problem position is in the middle of the run.

By blowing transformers I mean they just fail. There is no sign/smell of them burning out at all.

Hope this extra info clarifies.

 

[securespark]

And in each case, you are sure that replacing the transformer cures the problem?

Is there loft insulation in the void? Is the tranny close to the fitting?

Heat could be causing the thermal cut-out to trip.

Is there any possibility it could be something else, ie lamp or lampholder or connections?

Are all the transformers you've been using the same brand?

I like Osram Halotronic transformers: never failed for me or my customers yet.

 

[djrichie_t]

I dont like lighting transformers at all, they have been the cause of a few fires (even though installed correctly and able to handle the load) - often you will find cheap chinese ones supplied with fitting kits.

If possible, change your 12v light fittings to 240v GU10 ones and use the megaman 11 watt energy savers, these run cooler and actually give out decent light, drawing one third of the power.

If you have to stick with using low voltage lighting, check these out for transformers, extremely well built...

http://www.airlinktransformers.com/lighting.asp

toroidal ones are the best to go for, but remember these do take a switch-on surge, so you might want to uprate the MCB on the lighting circuit to a 'C' rated one rather than the standard B rated, otherwise it may keep tripping when you switch the lights on.

 

[DonnyO]

Thanks for the advice so far.

Yes there is loft insullation in the ceiling cavity but is not around the transformer plus there is an air flow across transformer so don't think its getting too hot.

I've tried two manufacturers SI Lite model T60 and Lytlec model LEB 60D.

Have to say I'm still stumped as to why these transformers are failing.

Any other ideas much appreciated.

Thanks

 

[333rocky333]

Next time one fails I would connect a lamp direct across the 12v output wires , to confirm it was the transformer that has failed and to eliminate the fitting,wiring and holder