Can I DIY replace downlight transformer?

[mreddie]

Yes I know what the answer is and you're going to shoot me down in flames... but I'm tired of calling in a sparky every time one of my downlight transformers die. I've seen how they work and how he screws the wires back in .... how unsafe is it for me to replace one of these myself and match the wires as per the transformer being replaced, shutting off all power etc. I know the right answer yeah yeah... but come on surely I could do this technically and save some coin......?

 

[Dustydazzler]

As this is deemed maintenance then any competent person can change a light. No different than changing a plug top...

 

[James]

Without knowing your practical skills, a definite yes go ahead and diy it is not my advice.

however, a like for like replacement is not beyond the skills of a competent diy person.

things to look out for.
ensure cables are neatly contained in a proper enclosure, sometimes there are more than you expect to find and they won’t all fit in the transformer terminals.
this is often the case with the first light in the room, as it has the feed, switch cables and a further feed out to other lights.

no taped up joints to be hidden in the ceiling

invest in a pair of wire cutters, a decent screwdriver and a 2 wire voltage tester.
never trust a non contact ”volt stick” they often give a false reading.

always photograph what is existing before taking apart.

most importantly, turn off power and using voltage tester, prove that all cables are dead before commencing work.

 

[littlespark]

And, additionally.... if the transformers are going kaput regularly, check for insulation around them.

also check your lamps. Transformers are for 12v halogen lamps (the ones that get rally hot) whereas LED lamps require drivers.

Suggest swapping out the transformer/lamp combo for 230v GU10 LED. Less joints that can go wrong, and they should use the same size hole in the ceiling.

 

[Dustydazzler]

I’m often converting old 12v DLs to mains LED lights, especially when the customer complains about transformers not lasting very long

 

[telectrix]

I’m often converting old 12v DLs to mains LED lights, especially when the customer complains about transformers not lasting very long

not a new concept. St. Peter converted heathens to Christianity 2000 years ago. ??

 

[Mike Johnson]

What give you the right to call me a heathen. ?

 

[telectrix]

What give you the right to call me a heathen. ?

thought you supported man.u.

 

[Mike Johnson]

Arsenal!

 

[SparkyChick]

also check your lamps. Transformers are for 12v halogen lamps (the ones that get rally hot) whereas LED lamps require drivers.

This point keeps coming up... not least at one of my wholesalers where they are adamant that MR16 LED lamps require drivers.

LED MR16 lamps are designed as direct replacements for Halogen MR16 lamps. The connectors used are polarity independent and I have yet to find one that states it requires 12v DC. In fact I've looked at those available from my regular wholesalers and they all state 12v AC.

The biggest issue with switching over to these is that alot of older 'electronic transformers' are actually switch mode power supplies which are incapable of regulating properly at powers less than their specification. These may typically say something like 20-50w. If you have 2 or 3 LED MR16s, they will draw between 12-15w which is less than the power supplies minimum and it won't be able to regulate properly.

Old wirewound transformers don't have this problem, nor do things like the 'transformers' from Varilight which will regulate properly down to 0w.

Drivers are required for things like LED tape which is polarity dependent because there is no room for the additional circuitry required to convert AC to DC (typically four diodes and at least one sizeable capacitor for smoothing), that and the fact you can cut the tape so you would need those additional components at regular intervals which would result in losses, additional expense and many additional points of failure.

 

[telectrix]

Arsenal!

that's even worse. ?