Replacing gu5 downlights with gu10

pieroabcd

Hi,
In my new home I've found a plethora of downlights.
Initially I thought "oh how nice that they are all the same" but in reality they're all different!
All switches are dimmers, and this is good.
Most of the lights are GU10, but I also have a lot of the dreadful GU5.3. In some cases I have lights that seem to be sll in one blocks where there's no way to remove the bulb from the fitting, even in bedrooms.

Since I'm a staunch believer in "one size must fit all" principle I want to replace all gu5 3 fittings with GU10.
I know that the former uses 12V instead of 220V and it relies on a transformer, but where is it? In the dimmer or in the ceiling before the light bulb?
Is it possible to reuse with GU10 the same cables and dimmer that the current GU5.3 lights are connected to or do i have to replace them? The cables are old and definitely thin.

The current light bulbs are almost always halogen (20, 35, 50W), while the replacements that I've bought are 7W dimmable LEDs.

Thanks 

plumb1_2

Usually in the ceiling, you’ll have to pop a fitting out and check the wires 

km1500

in the ceiling resting on the plasterboard

pieroabcd

I've tried to pull a bit without insisting too much  but I haven't seen anything coming from the ceiling

Chickereeeee

GU5.3/MR16 downlights often have a smaller hole cutout than GU10s (65mm versus 75mm in my case) and it is a pain to enlarge a cutout. I used combined (all in one) 240v fittings to replace the 65mm 12v, transformer-driven, GU5.3 downlights in the bathroom. IP rated, fire rated, insulation coverable and about £8 each.

pieroabcd

Of which unfortunately I have loads. The wires in the bathrooms are very short, a real pain to fix in the fitting

FFHillbilly

pieroabcd said:

I've tried to pull a bit without insisting too much  but I haven't seen anything coming from the ceiling

unfortunately, this can be a problem. I've discovered 12v transformers clipped to joists, or sometimes a remote transformer in another room or part of the building. hiring / borrowing an inspection camera, or taking the floor up above would be the next steps, assuming you have inspected from below thoroughly, i.e checked every 12v light you wish to replace

Chickereeeee said:

GU5.3/MR16 downlights often have a smaller hole cut-out than GU10s (65mm versus 75mm in my case) and it is a pain to enlarge a cut-out. I used combined (all in one) 240v fittings to replace the 65mm 12v, transformer-driven, GU5.3 downlights in the bathroom. IP rated, fire rated, insulation coverable and about £8 each.

I don't think there's any correlation between the base type and the size. yes all lights are different sizes but it's nothing to do with GU10 or 12v. most fittings just hold the front of the bulb anyway, so you can re use the front part, just replace the bulb holder at the back and you don't need to do anything with the hole size in the plasterboard

Chickereeeee

There is not a strict correlation with cutout size (I just said often) but in 4 houses I have done, all the 12v Mr16/GU5.3 ceiling downlights were smaller (65mm) and  all the mains GU10s where about 75mm.

pieroabcd

I've given a better look. The 4 gu4 fittings are connected to a single transformer that is in the eaves, very close to the rockwool layers. 
Since this loft extension was done recently I'm wondering if there's a requirement to have this setup because of the rickwool or if I can ask the electrician to provide 4 lines at 220V to feed GU10 lamps.

Something curious was done in the bedrooms: there are IP65 lamps that so far I've seen used only in bathrooms. Even in this case there's some rockwool around them. Can they be replaced by GU10 fittings?

I've searched if there are regulations for this stuff when there's rockwool in the proximity but I haven't found anything that looks more accurate than hearsay.

Chickereeeee

pieroabcd said:

I've given a better look. The 4 gu4 fittings are connected to a single transformer that is in the eaves, very close to the rockwool layers. 
Since this loft extension was done recently I'm wondering if there's a requirement to have this setup because of the rickwool or if I can ask the electrician to provide 4 lines at 220V to feed GU10 lamps.

Something curious was done in the bedrooms: there are IP65 lamps that so far I've seen used only in bathrooms. Even in this case there's some rockwool around them. Can they be replaced by GU10 fittings?

I've searched if there are regulations for this stuff when there's rockwool in the proximity but I haven't found anything that looks more accurate than hearsay.

Many downlights nowadays are designed to be simply daisy chained, sometimes with push-fit connections. So, depending on your layout, you may only need one mains voltage feed to the nearest dowlight. It is also possible that suitable wiring was used for the 12v connection to allow the transformer to be removed, and mains voltage supplied starred fro the ine point, as now. Your electrician will advise.

pieroabcd

Oh this beast came back to haunt me.
Sìnce the halogen bulbs were very dim I replaced them with dimmable LEDs (that are very expensive).
It turned out that both with a dimmer and with  a plain light switch those LEDs flicker a lot.
The only way that I've found to stabilise them was adding back an halogen.

This reminds me of another experience, where I had to add back an halogen in the middle of a chandelier to shut down all LEDs when the switch is off.

Still, I don't understand why the lights should flicker.
I'm confident that the source of electricity is a derivation from the loft conversion. Could it be that?