Swapping out lighting transformer - LED compatibility
Discussion
Hi all,
In our ensuite, we have a 5 halogen downlighter bulbs (MR16).
A couple of them went, so I thought I'd replace the lot with LED bulbs - which I did, using 5W LED bulbs.
However, with all 5 LED bulbs fitted, the lights just flash. Replace one LED with a one of the original 20W halogen bulbs, and it works OK - but switches off after about 10 minutes.
So I'm thinking I need to replace the transformer.
Luckily, access is pretty good from the loft. I lifted some boards and found this:
Looks like a sealed unit with 2 grey wires (presumably one to the lighting circuit, the other to the bulbs).
Any recommendations on what to replace it with, for the easiest DIY swap over?
I found this very similar looking transformer on eBay which says 20-50W. That would seem to fit in with what I need (total of 25W), but not sure what else I need to look out for?
Thanks!
In our ensuite, we have a 5 halogen downlighter bulbs (MR16).
A couple of them went, so I thought I'd replace the lot with LED bulbs - which I did, using 5W LED bulbs.
However, with all 5 LED bulbs fitted, the lights just flash. Replace one LED with a one of the original 20W halogen bulbs, and it works OK - but switches off after about 10 minutes.
So I'm thinking I need to replace the transformer.
Luckily, access is pretty good from the loft. I lifted some boards and found this:
Looks like a sealed unit with 2 grey wires (presumably one to the lighting circuit, the other to the bulbs).
Any recommendations on what to replace it with, for the easiest DIY swap over?
I found this very similar looking transformer on eBay which says 20-50W. That would seem to fit in with what I need (total of 25W), but not sure what else I need to look out for?
Thanks!
Have a look for led drivers. I've done this on a cloakroom mirror, converting the 100w of capsule halogen bulbs to led equivalents.
Original transfomer wouldn't work so I got an led driver transformer rated at just over the correct wattage total... and now it'll work but very faintly flicker after a few minutes. Junk!
I'd stick to Screwfix or Toolstation or somewhere you can easily return stuff when it's true chineseum quality rating becomes apparent.
Original transfomer wouldn't work so I got an led driver transformer rated at just over the correct wattage total... and now it'll work but very faintly flicker after a few minutes. Junk!
I'd stick to Screwfix or Toolstation or somewhere you can easily return stuff when it's true chineseum quality rating becomes apparent.
Geffg said:
Be better to replace the lampholders to gu10 ones, do away with the transformer and fit mains powered led lamps.
Exactly this. We do all of Wagamama's electrical work and we're swapping their whole estate to GU10s instead of MR16s. The transformers are getting to be unobtanium and the lamps are increasingly harder to find.DorsetSparky said:
Geffg said:
Be better to replace the lampholders to gu10 ones, do away with the transformer and fit mains powered led lamps.
Exactly this. We do all of Wagamama's electrical work and we're swapping their whole estate to GU10s instead of MR16s. The transformers are getting to be unobtanium and the lamps are increasingly harder to find.Before I went to change the bulbs, I thought they were GU10, because the fittings look the same as in our main bathroom (which are GU10).
100% swap the whole unit for LED GU10.
MR16s are nasty things and even if you swap the halogen bulbs for LED versions they still run hot. Also not very efficient as you have 2 sets of step down transformers in the chain to each bulb.
I had a very cathartic day swapping out about 30 MR16s which had been nothing but trouble from the day they were installed - I tried the LED bulbs in then too and they were crap and unreliable.
MR16s are nasty things and even if you swap the halogen bulbs for LED versions they still run hot. Also not very efficient as you have 2 sets of step down transformers in the chain to each bulb.
I had a very cathartic day swapping out about 30 MR16s which had been nothing but trouble from the day they were installed - I tried the LED bulbs in then too and they were crap and unreliable.
stevesuk said:
Was just learning more on YouTube - the MR16 bulbs I have at the moment run off a central transformer. But, GU10 bulbs have the transformer built in to the bulb, so you just wire the light fittings in to the lighting circuit. Is that an accurate summary of the difference?
So the lighting circuit goes in and out of the MR16 transformer (or in if it's end of line), to which there is a low-voltage cable from the transformer to the MR16 lamp.With the GU10, you just wire straight in and out of the fitting itself. Lots of good options for GU10s. I often use the JCC Fireguard GU10 fittings, but lots of others are available too.
stevesuk said:
Just to clarify - this would mean swapping out just the wiring and plugs, not the spring loaded fittings that push up in to the ceiling?
Before I went to change the bulbs, I thought they were GU10, because the fittings look the same as in our main bathroom (which are GU10).
You'll want to replace it all. Pull out the wiring, the plugs, and the fitting itself. Obviously (or not!) measure the size of your cutout, as the new fittings will be available in various sizes, and unfortunately there isn't always a standard. Before I went to change the bulbs, I thought they were GU10, because the fittings look the same as in our main bathroom (which are GU10).
Pretty much. It’s an old fashioned installation if you’ve got one transformer for multiple MR16 luminaires - more common in the last 10-15 years to have one transformer per MR16.
A modern LED GU10 bulb has an integrated transformer to go from 240V to 1.5V, so you just wire the mains in a daisy chain to each GU10 holder. Aurora make nice units which have click down terminals (a bit like a wago) which makes wiring up replacements fairly quick.
A modern LED GU10 bulb has an integrated transformer to go from 240V to 1.5V, so you just wire the mains in a daisy chain to each GU10 holder. Aurora make nice units which have click down terminals (a bit like a wago) which makes wiring up replacements fairly quick.
DorsetSparky said:
So the lighting circuit goes in and out of the MR16 transformer (or in if it's end of line), to which there is a low-voltage cable from the transformer to the MR16 lamp.
With the GU10, you just wire straight in and out of the fitting itself. Lots of good options for GU10s. I often use the JCC Fireguard GU10 fittings, but lots of others are available too.
Just had a look at those JCC Fireguard fittings - look really simple to fit (assuming our existing cut out is ~ 74mm... I need to check that). I assume that the lighting circuit mains feed that currently goes to the transformer, I'd instead wire that in to the first lamp fitting. Then I'd run a cable out of that fitting to the next one... and so on until I reach the last one? With the GU10, you just wire straight in and out of the fitting itself. Lots of good options for GU10s. I often use the JCC Fireguard GU10 fittings, but lots of others are available too.
Edited by stevesuk on Friday 6th December 22:18
stevesuk said:
Thanks all - sounds like a winter project. Safe for an enthusiastic (but careful) amateur?
If you're anything like competent, absolutely.I swapped my parents' kitchen lights over to mains GU10s from low voltage MR16s in no time at all, despite no access from above which meant I had to cut some plaster board out to get at the old transformer and incoming 240v.
The new GU10s are so simple to wire up - they usually loop into each other and have snap connectors that you don't even need a screwdriver for.
Remember to leave yourself a decent length of spare cable so you can drop the lights down to work on them from below if you ever want to swap them, and you should never need to access them from the loft again.
stevesuk said:
Just had a look at those JCC Fireguard fittings - look really simple to fit (assuming our existing cut out is ~ 74mm... I need to check that). I assume that the lighting circuit mains feed that currently goes to the transformer, I'd instead wire that in to the first lamp fitting. Then I'd run a cable out of that fitting to the next one... and so on until I reach the last one?
Yes. Exactly that.PorkInsider said:
stevesuk said:
Just had a look at those JCC Fireguard fittings - look really simple to fit (assuming our existing cut out is ~ 74mm... I need to check that). I assume that the lighting circuit mains feed that currently goes to the transformer, I'd instead wire that in to the first lamp fitting. Then I'd run a cable out of that fitting to the next one... and so on until I reach the last one?
Yes. Exactly that.I'll then need some cable to join them. I assume twin and earth (and maybe some earth sleeving for the ends). However, twin and earth cable seems to come in a variety of thicknesses, from 1mm upwards. What would you guys recommend for this job?
Really appreciate all the advice.
1mm T+E is usually ok for lighting circuit, going up to 1.5mm for longer circuits to allow for voltage drop. As it might be hard to know how long your circuit is already, I’d be inclined to go 1.5mm as the cost differential is low and you don’t need much of it.
And some earth shroud for the tails.
And some earth shroud for the tails.
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