Low voltage halogen issue.

[yocky]

I had an "electrical incident" which caused some damage to 3 of the 6 low voltage halogen lights in my kitchen. A short caused some of the connectors between the transformers and the lights to become damaged, I replaced those and the lights seemed to worked fine.

Now I've got a seemingly separate problem where all of the lights work fine for 5 minutes or so then 3 of them turn off simultaneously. If I turn the switch off for a while then on they work again for a while then the same happens. I thought it must be the transformers cutting out but I've measured the voltage before the transformers and it's the mains voltage that seems to cut out. The other three lights are unaffected by all this.

2 of these problem lights were damaged in the first incident, one was fine before I "fixed" things.

Any clues?

[john]

Tell us what you did to break it! It will be easier to suggest a solution. I was about to suggest the transformer. If you can see that 240v is vanishing after a few minutes I would say it is a faulty light switch. Did you blow the whole system by connecting the mains across the switch? If it is an electrical (switching mode) power supply then it might be damaged, but you said that 240v is stopping reaching it in a few minutes. If the main fuse in the consumer unit for that circuit isn't blowing or circuit breaker tripping - there is only one thing between the mains and the transformer!

[yocky]

I messed about with a ceiling rose in a diiferent room without knowing what I was doing, when I put the fuse back in the fuse box there was a loud bang and the fuse went. Looking at the fuse wire in the lighting circuit it seemed to be the same diameter as the other fuses which I know shouldn't be the case. I've got a 5 amp fuse in there now.

I assumed I'd damaged the transformers so I bought some more but the old ones seem to be fine, as do the bulbs.

I can't see how the switch can be at fault as only 3 out of 6 lights are affected.

[meow2222]

Now that you know guessing is pointless, time to use a multimeter to see at what point the mains supply disappears when the lights fail.

NT

[yocky]

Well obviously it's after the switch that supplies all 6 lights. I just don't see what can be happening between the switch and the three lights that are turning off. Most of the wiring is inaccessible in the roof.