Converting Low Voltage Downlights to Mains Voltage

[Dave78]

I didn't know if this should be in here (as after advice) or in the lighting section - apologises if it's in the wrong area.

I was looking at the wiring last night in my mates loft, as he's currently got low voltage downlights installed, but he's thinking of replacing them for 240v - largely as a couple of his transformers have stopped working and each downlight has it's own transformer. And as I happen to have some 240v downlighters (Class 2) in my loft doing nothing.

They were installed by the previous owners and you can just make out the filled in hole from where the old ceiling rose was in the middle of the room. Above it there's a junction box with the standard wires of Power In/Out, switch and what would have been the output to the light - now in 1.0mm sq T&E. Then daisy chained through Halolite boxes, the outputs of which go to a transformer then onto the 12v downlight. See attached pic

Must be said I'd not heard of Halolite boxes before, but they just seem to be another type of screwless loop in/out with a N&L supply output. I've sure they's a better way to describe this. But it's this from Screwfix (am sure other suppliers are available). According to what's on the box it's rated to 8A

He was wondering whether it's possible to disconnect the transformer and wire the 240v downlighters directly from the Halolite's N&L supply with 2 core heat resistant flex, thereby leaving all the other wiring alone. Already noted that the downlighters in this case would have to be class 2 as no earth wire (which mine are if he used them). He's wanting to use LED GU10, but I've suggested that someone might well replace the LED for halogen in the future.

Thought I'd ask on here, as normally I'd have just used a standard screw terminal junction box, although more recently have gone to using Wago. No experience or knowledge of these Halolite junction boxes.

Thanks all, and hope it all makes sense.

 

[telectrix]

just swap the downlights. connect the 1.0mm direct. use LED GU10s. job done.

 

[westward10]

Do those joint boxes incorporate cord restraint.

 

[Dave78]

Do those joint boxes incorporate cord restraint.

Nope. From memory the box was attached to the joist, and all cables clipped to the joist next to the entry/exit locations.

 

[westward10]

If you are using flexible cable they should be restrained with a clamp incorporating a two point fixing and not by the lid pressing down on them. You could replace them with Hager J501 boxes which are about £1.50 each.

 

[SparkyChick]

Personally I would use 3 core flex rather than 2 core. If the fittings don't need the earth then clip it off at the fitting, but at least the cable will have the protection afforded by the CPC.

 

[Dave78]

So replace the Halolite boxes with a downlighter box (of whatever make), and run heat resistant flex done and into the downlighter - job done.

Would you move the location of the downlighter box (currently they are next to the downlighter and under loft insulation - wonder if that's what caused the transformer to go ) esp as there's talk of putting in loft boards for storage - sort of place them (downlighter box) in an easy to access place - even if this means the flex run is a little longer?

Picking up on your comment sparkychick about clipping the earth at the fitting, I've read else were on here that it should be terminated and not just clipped? Unless that's the same thing with different terminology.

Was talking about this to one of the guys at work this morning, as he's just had surewire junction boxes put in for his downlighters. He wasn't sure if heat resistance flex was used, but if it was then would be run all the way from there and up to the surewire junction box - as otherwise you're surely adding in another downlighter junction box anyway to go from the heat resistance flex to the T&E? As surely the less junctions/connections the better (the whole less to go wrong)

I wonder how many different ways there can be to wire up some downlighters

 

[SparkyChick]

About the clipping, what I meant was to simply clip the CPC off at the end. The reason it should be terminated properly or kept away from the fitting is if the fittings are double insulated with metal cans, if the earth isn't properly terminated and possibly long enough to touch the can (or other metal work of the fitting), you've just undone the double insulation by virtue of the CPC being able to introduce a potential to a component that should (by design) be isolated. It all depends I guess on the fitting and available cable entry. You could leave it long, bring it back outside the can and pop a lever Wago on it.

What I've done in the past (rightly or wrongly - happy to be educated) is brought the flex into the fitting, clipped the earth off level with the end of the sheath and then wrapped the end of the sheath in a few wraps of tape to add a barrier. The key thing I think is be sensible and consider the impact of the CPC coming into contact with the fitting itself.

Based on what you've said about insulation, yes, that could have been a contributing factor to the failure of the transformers. I would consider moving the boxes out of the way especially if the loft is going to be boarded, making sure none of the cables cross the ceiling beams as it seems people think it's perfectly acceptable to just put the board down over cables.

Yes, less junctions means less to go wrong. Whether you use heat resistant flex... check the manufacturers installation instructions. Modern LED fittings do not get anywhere near as hot as the old halogen ones do and so may not require it. If you are in any doubt, use heat resistant.

 

[Specialist]

Won't argue on using 3 core as opposed to 2 core. But when you clip the Earth at the fitting, I'd use Heatshrink as opposed to tape.
Over time with the heat of the fitting the adhesive on the tape will deteriorate and the tape tend to unravel.

 

[SparkyChick]

Won't argue on using 3 core as opposed to 2 core. But when you clip the Earth at the fitting, I'd use Heatshrink as opposed to tape.
Over time with the heat of the fitting the adhesive on the tape will deteriorate and the tape tend to unravel.

Good point, I do tend to try and clamp it for that reason, but still good point

 

[LankyWill]

Most fittings (double insulated) state that earth terminal is for 'connection purposes only' when double insulated. We had a Batch where the terminal was there for the earth core to be terminated but inadvertently no core on the other side attached to the fitting. Might save you messing about with heat shrink.

 

[Dave78]

Went and had another look last night (as was around his house anyway). Where the Halolite boxes have been attached to a joist and wired in there is little to no slack between the boxes. As the in/out are on different sides of the box and cut to length there is no change of them being able to made to fit a same side entry box sure as the Hager J501 recommented above.

Anyway, with therefore having to replace the T&E between the JB's, and wanting to relocate them (so not under insulation and/or loft boards), he and I were wondering what the preferred wiring option would be (Pic's of each option).

a) Wire to individual JB's above the loft boards - then (3 core) Heat Resistance from them to the downlighters , or
b) Wire all downlighters to a single JB in (3 Core) Heat Resistance, prehaps something like a surewire junction box. Or even replacing the whole thing with a surewire box in incorp everything (In/Out, Switch, and all downlighters).

Which (if either) would be considered the preferred option, and what are the general views if you were to see flex cable (the heat resistance from the downlighters) running up into a junction box? I know that could use maintenance free junction boxes and leave them under the loft boards - would this be any better than using them and leaving them above the loft boards easy to test/check in the future.

Thanks once again