Switched low voltage halogens to 240v LED, but strange issue

[flanajb]

Hoping someone might have an idea here. I replaced the kitchen low voltage halogens with 240v LED ones, but one of the lamps on a spur off the circuit just does not turn on. I have one of those pen testers and can detect a current flowing as when I turn the lights off the thing stops beeping.

If I hold the tester on the bulb it beeps, turn the lights off it stops beeping

I have tried a different bulb, and also replaced the GU10 lead to the bulb, but it still won't turn on.

Rather lost with what to try next. All I can think is that there is not enough voltage at the lap to power the bulb, but given the transformer has been removed I am rather perplexed.

Anyone have any ideas

 

[RogerS]

Lost your neutral.

 

[Lons]

Lost your neutral.

+1

Would be the first thing I'd check as well

 

[flanajb]

Cheers chaps. Now need to try and work out how that has happened.

 

[Phil Pascoe]

No connection in the spur junction box? Or check that you've got contact on both sides of the lamp holder?

 

[RogerS]

Or you may be screwed down on the insulation of the neutral leaving the bare wire floating in mid-air and making contact with nowt

 

[Lons]

Or you may be screwed down on the insulation of the neutral leaving the bare wire floating in mid-air and making contact with nowt

:lol: :lol: :lol: Been there, done that

 

[Jonzjob]

Do 240v LEDs work on 12v :roll: :roll:

OK I'll get me hat :mrgreen:

I'll go along with a lost neutral too.

 

[markturner]

Do 240v LEDs work on 12v :roll: :roll:

OK I'll get me hat :mrgreen:

I'll go along with a lost neutral too.

There is a transformer to step the voltage to 12v...............so just ditch the transformer.

 

[Phil Pascoe]

The OP said he'd removed the transformer.

 

[Jonzjob]

Oh dear 8)

When did humour die :mrgreen: :mrgreen: :mrgreen:

 

[Phil Pascoe]

Sorry, I've looked for it - still can't find it .

 

[Dee J]

Was there just one transformer for all the lights? Could this lamp be on a separate transformer? (many low voltage setups have one Transformer per fitting). Also if you've removed a transformer supplying a set of lights, but re-used the wire at mains voltage... was it 230v rated cable? If you can't access the wiring then it may be simpler to retain the transformer and use 12v leds maybe?

 

[Tom K]

Haven't played with 240v LED's but do know 12v ones in automotive applications only work one way (cuz they is diodes see) so if the wire pair to that "bulb" is twisted it'll never work.

 

[Phil Pascoe]

What was the purpose of the change? Most things I read about LED's advise people not to have 230v, and say that 12v. is preferable.

 

[flanajb]

The existing low MR16 lamps just kept getting hot and the terminals on the bulbs became tarnished and stopped working. I had to replace the lamp leads as some of them had melted.

All of the sparkies I have spoken too have said 12V LED lamps don't make any sense and as such go with 240v 12V LEDs don't seem to be readily available

 

[RogerS]

What was the purpose of the change? Most things I read about LED's advise people not to have 230v, and say that 12v. is preferable.

Doesn't really matter, Phil. More a question of what's to hand or styling of the fitting. They've still got to have 230v to power the light. Where it gets stepped down (internally on the lamp) or externally via a transformer or switch mode power supply yields the same result.

 

[Dee J]

http://www.tlc-direct.co.uk/Main_Index/ ... index.html
Seems like these are polarity independent.

Ordinarily I'd recommend mains voltage on a new install, or at least mains voltage wiring to each lamp position. But trying to work blind - just from whatever is accessible through the ceiling cut-outs will always throw up oddities - especially if you're trying to re-purpose low voltage wiring for 230 volts and your testgear consists of a voltstick. How are you checking continuity of the cpc (earth) or the earth fault loop impedance at each lamp position. Discovery and diagnosis of the problem reported here should have happenned well before trying to make the lamps work.

Low voltage LED installation would have been a case of minor repair to heat damaged items - not a full re-design of the wiring.

Dee

 

[RogerS]

Seems to me we have gone way off topic and over-complicating things.

flanajb...have you checked the neutral connection is good?

We have the lamps that Dee J links to. Took us ages to get the right wattage/colour temperature. Personally I prefer the old halogen bulbs that we took out. The beam angle was certainly better than that from these LED bulbs. They also cause interference on FM.

 

[Dee J]

But it is complicated... trying to fault-find wiring with a voltstick.
You need to be diagnosing this WITH THE POWER OFF. You will need some sort of continuity checker (cheap Digital meter or even the classic torchbulb, battery and wire setup). You need to check you have continuity everywhere it should be, and not where it shouldn't.

But I'm concerned by the OP statement that the misbehaving lamp 'is on a spur'... can you actually see enough of the wiring to really say that... or do you mean this lamp is physically separated from the rest of the group. If so I'd suspect it's on a second transformer. I wouldn't trust a voltstick to distinguish between 12 and 240 volts. If I were a betting person I say that there's good odds on that - but I'm not, I'm an electrician- but I'd certainly test for that.

Dee