12v Spotlight Failure

[Sallyday10]

Hi,

I'm looking for some advise please. U.K. 240v circuit.

My mother in law has a set of 5 12volt spotlights in her bathroom that have suddenly all stopped working.

I've checked the voltage coming out of one transformer and I have current (not measured the voltage though). I've also tested continuity from the connector through the bulb itself and it all works fine. I replaced the pull switch in the bathroom itself and this too has power and is now brand new.

So, given my limited knowledge, it would appear that the transformer is pushing out some voltage, (my cheap screwdriver lights up) but not enough to light the 12v bulb.

Is it typical for transformers to fail like this, still pushing out some juice but not enough to power a 12v bulb or am I missing something?

Thanks all,

Mike.

 

[Dustydazzler]

Neon screwdriver alert

Please dint use this to prove dead or alive

Get an electrician round to replace the transformer

 

[Spoon]

Hi,

I'm looking for some advise please. U.K. 240v circuit.

My mother in law has a set of 5 12volt spotlights in her bathroom that have suddenly all stopped working.

I've checked the voltage coming out of one transformer and I have current (not measured the voltage though). I've also tested continuity from the connector through the bulb itself and it all works fine. I replaced the pull switch in the bathroom itself and this too has power and is now brand new.

So, given my limited knowledge, it would appear that the transformer is pushing out some voltage, (my cheap screwdriver lights up) but not enough to light the 12v bulb.

Is it typical for transformers to fail like this, still pushing out some juice but not enough to power a 12v bulb or am I missing something?

Thanks all,

Mike.

Welcome to the forum mate.
I wouldn't trust your cheap screwdriver test results.
You could do better tests with a cheap digital meter to chect the 12v from the transformers, or better still, get an electrician round to test it all for you.

 

[westward10]

If each fitting has a separate transformer and they have all failed you may have a connection breakdown prior to the first fitting.

 

[dmxtothemax]

More likely is that you have power at the transfomer but a bad connecttion somewhere.
low voltage high current only needs a small resistance to have a major impact on the output.

 

[Sallyday10]

Thanks for the replies.

The lights have worked for many years, failing only recently.

Is it possible that the transformers have failed, but are still providing SOME power to the bulbs, albeit not enough to light them?

Thanks,
Mike.

 

[Spoon]

Thanks for the replies.

The lights have worked for many years, failing only recently.

Is it possible that the transformers have failed, but are still providing SOME power to the bulbs, albeit not enough to light them?

Thanks,
Mike.

Its highly unlikely that all 5 transformers have failed at the same time.
I'd go with the above and that you may have a bad connection somewhere.

 

[Dustydazzler]

Could a single transformer be feeding more than one light...?

In recently did a small job where a customer had a 105w transformer feeding 5 lights , original would be 20w lamps I presumed

But where the customer had replaced lamps for 50w it had burned the transformer out

 

[Sallyday10]

Its highly unlikely that all 5 transformers have failed at the same time.
I'd go with the above and that you may have a bad connection somewhere.

Could the bad connection mean that the bulb is still receiving SOME juice but not enough to light it.

 

[Spoon]

Could the bad connection mean that the bulb is still receiving SOME juice but not enough to light it.

As before mate. You are using a cheap screwdriver tester... These things are rubbish.

 

[Sallyday10]

As before mate. You are using a cheap screwdriver tester... These things are rubbish.

I'm back at the house now, armed with a multimeter.

There is one transformer powering all 5 lights.

 

[Spoon]

I'm back at the house now, armed with a multimeter.

There is one transformer powering all 5 lights.

Have you done any tests with the meter?

 

[Sallyday10]

As before mate. You are using a cheap screwdriver tester... These things are rubbish.

Ok so tested positively at 240v into the transformer, 0 volts coming out. New lights installed, transformer in bin.

Thanks for your help, I'll keep the screwdriver for driving screws.

Mike.
[automerge]1569768300[/automerge]

Ok so tested positively at 240v into the transformer, 0 volts coming out. New lights installed, transformer in bin.

Thanks for your help, I'll keep the screwdriver for driving screws.

Mike.

[automerge]1569768444[/automerge]
The new lights are 240v LEDs, there are 5 of them. I've installed one, but now need to link it to light number 2, 2 to 3 etc. What is the correct cable specification for this please? Solid copper or multi-strand? Thanks, Mike.

 

[Risteard]

Ok so tested positively at 240v into the transformer, 0 volts coming out. New lights installed, transformer in bin.

Thanks for your help, I'll keep the screwdriver for driving screws.

Mike.
[automerge]1569768300[/automerge]

[automerge]1569768444[/automerge]
The new lights are 240v LEDs, there are 5 of them. I've installed one, but now need to link it to light number 2, 2 to 3 etc. What is the correct cable specification for this please? Solid copper or multi-strand? Thanks, Mike.

If you are in the 26-Counties then you must ensure that the cable is compliant with Irish Standards, e.g. in the case of T&E type cable this must be to I.S. 201. This is NOT available in Woodies - they stock a prohibited cable type bizarrely.

 

[Sallyday10]

The new lights are 240v LEDs, there are 5 of them. I've installed one, but now need to link it to light number 2, 2 to 3 etc. What is the correct cable specification for this please? Solid copper or multi-strand? Thanks, Mike.

If you are in the 26-Counties then you must ensure that the cable is compliant with Irish Standards, e.g. in the case of T&E type cable this must be to I.S. 201. This is NOT available in Woodies - they stock a prohibited cable type bizarrely.

I'm in Cheshire, UK.