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Downlight Issue That Trips Main Fuse After Changing Lights to LED's

Postby Gepa » Mon Dec 12, 2016 11:46 pm

Hello all.

In my living room I have a 2 gang switch (think) it is a switch with 2 buttons on it one operates the main light and the other operates 10 down-lights. they are either on or off

After getting a new smart meter I decided to swap the halogen down lights for led bulbs in the living room and in the dining room this was a big mistake.

After swapping them only a couple of the lights worked I had a friend look at it who installs electrics for a living but he cant get the down lights to work.

I have gotten a new transformer in case it was that but it makes no difference when he wires it up as soon as you turn on the down lights it blows the main trip in the fuse box. There is 3 main cables that goes in to the switch 2 live and 2 that is not live not sure what that feeds.

anyone know how this should be wired up.
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Postby kbrownie » Tue Dec 13, 2016 10:24 pm

Have you altered any of the wiring, fittings or switches?
or just swapped lamps (AKA bulbs)?
Could you post a picture of switch and the lamps you have replaced?
I assume they are 12V if you are talking about transformers, the issue could well be that you have not changed the transformers, as they need to be compatible with LED lighting and LED lights require drivers not transformers.

Your electrician friend should be well aware of that.
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Postby ericmark » Wed Dec 14, 2016 11:17 am

I find the GU5.3 MR16 12 volt fitting a problem when using LED's.
With a simple transformer you just swap the quartz lamp for a LED lamp with same voltage marked for 50Hz.

However we tend to use electronic transformers which are not really transformers as such, these units correct the voltage and were better with quartz but often marked 50 ~ 105 VA rather than 0 ~ 105 VA you get with a real transformer and with LED's of less than 50W they are under loaded, also output in kHz range not 50 Hz.

LED's do use drivers, these limit current not voltage, but are often built into the lamp rather than used as separate items, however some manufactures miss label DC power supplies as drivers so one has to be careful.

You can get DC only lamps, often much more expensive and with a voltage range of 10 ~ 36 volt, mainly used for caravans. But most GU5.3 lamps are AC they don't say AC they say 50 Hz and you can't get 50 Hz with DC.
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