ELV down lighters fault- 4 failed at once!

[catdog]

morning lads,

Right so was just going to change some sockets in my own house this morn.... had my socket tester bleeping away and flicking through MCBS (couldnt remmeber which circuit was on as is old house) and saw the light flicker (was only turning off socket MCBS mind). Eventually found socket circuit as my socket bleeper cut out and around same time heard a bang and in bathroom, 4 out of 5 downlighters went out.

So in bathroom have 5 ELV down lighters. 4 of which are halogen 50w's-all of which went out at once. The other is an LED ELV which was the one i noticed flickering more before the other 4 went out.

As it stands there is 230 at all the 4 transformer's LV side with 0v at the ELV side. No obvious smell. The transformers have a 1Kv surge protection.

So any ideas?!

cheers.

shane.

 

[Lucien Nunes]

Electronic or wirewound transformers? Don't forget you often can't measure the output of electronic ones with a multimeter because it's HF AC and/or they won't start up without a lamp load.

I know what I would check if I saw flickering on a lighting circuit when I disturbed nearby MCBs in a CU. Presumably you have already checked them? Did you find signs of arcing or not being properly located?

 

[catdog]

Electronic or wirewound transformers? Don't forget you often can't measure the output of electronic ones with a multimeter because it's HF AC and/or they won't start up without a lamp load.

I know what I would check if I saw flickering on a lighting circuit when I disturbed nearby MCBs in a CU. Presumably you have already checked them? Did you find signs of arcing or not being properly located?

Thanks for a reply Lucien!

Yes electronic transformers- so yes good point!

Yes checked CU and all seems good. Going to do some other standard checks just now to rule out any neutral problems etc. The thing that gets me is that they all failed at the exact same time and was it a coincidence that i was turning MCB's off at the same time....

 

[Lucien Nunes]

Coincidence? There's mains at the TXs now, so I'd be looking for an intermittent that arced and killed them. They can often be found lurking under MCBs. why do you specifically expect to find it in the neutral? Report R1 & RN...

 

[catdog]

Yeah ok coincidence is a long shot! Was thinking neutral just as a starting point but doesnt seem likely now. R1 +R2 = 0.31. R1 + Rn = 0.38