Replacing GU5.3 Halogen with LED

CarPark2 · 26-06-2020 3:03pm #1

I posted in the Electrical forum, but no response there, so i was wondering if the DIYers ave any insight on this.
House built 2005. Bought it 3 years ago and have been replacing the halogen spots (GU-10) with LEDs over time. Went to replace the ones in the bathroom, but it turns out that they are GU-5.3
I had a quick google and it seems that it is not just a matter of taking out a GU-5.3 halogen and replacing with an LED. Is that correct? Do i have to get an electrician in to change a transformer? Where is the transformer located?

If i am getting an electrician to do that, would it be as easy to get them to chenge them to GU-10?

Thanks in advance.

GinSoaked · 26-06-2020 4:21pm

A quick look on Amazon gives me these https://www.amazon.co.uk/36-Degree-Equivalent-500-Lumen-6000-Kelvin-Boxlood/dp/B07DZPK6YQ/ and loads of others.

They take a 12V input the same as the original GU-5.3 Halogens. So nothing to change except the bulbs.

Lex Luthor · 26-06-2020 5:31pm

the transformer will be up in your attic if your bathroom is on the first floor just beside the bulb

i replaced all mine recently, they can get extremely hot

there will be 2 wires going into the transformer, just turn off the breaker to the lights in the bathroom, disconnect the 2 wires (live & neutral) and wire it directly into your new 230V LED fitting

A lot neater and safer I would imagine

CarPark2 · 26-06-2020 5:49pm

Lex Luthor wrote: »

the transformer will be up in your attic if your bathroom is on the first floor just beside the bulb

i replaced all mine recently, they can get extremely hot

there will be 2 wires going into the transformer, just turn off the breaker to the lights in the bathroom, disconnect the 2 wires (live & neutral) and wire it directly into your new 230V LED fitting

A lot neater and safer I would imagine

Thanks. Just so that i understand, are you talking about a scenario where i replace the GU5.3 with GU-10, or just where i replace the Halogen (GU5.3) with LED (GU5.3)?

26-06-2020 6:47pm

Lex Luthor wrote: »

i replaced all mine recently, they can get extremely hot

That is a worrying sign! Transformers such as these should not get hot.

CarPark2 · 26-06-2020 8:38pm

2011 wrote: »

That is a worrying sign! Transformers such as these should not get hot.

I presume Lex meant the bulbs get extremely hot.

26-06-2020 9:33pm

2011 wrote: »

That is a worrying sign! Transformers such as these should not get hot.

Every transformer will get hot because it's impossible to be 100% efficient!

26-06-2020 9:35pm

CarPark2 wrote: »

I presume Lex meant the bulbs get extremely hot.

I installed 1000s of them back in the day while sub contracting.
Pure ****e.
I don't know how there wasn't more fires from them.

whizbang · 26-06-2020 11:24pm

OP, you need to pull out all of the Bulbs in you bathroom, and figure out how they are connected. Transformers are usually left lying around in the ceiling, will pull out with the fitting.
Take out the transformer(s) and check the load rating on the label, post it up here.

Most often these are each 50Watt bulb connected to its own transformer, so you have as many transformers as lights.
Sometimes there are multiple bulbs connected to a single transformer. Probably 20Watt bulbs.

In the first case, chances are that the transformers will not work properly with just a single 5watt Led bulb.
- You could replace each fitting with a mains GU10 easily, but not recommended in bathroom.
- You could rewire all the fittings into a single transformer, like case 2.

In the second case, you just replace the bulbs, chances are transformer will work well with multiple Led bulbs.

CarPark2 · 28-06-2020 12:31am

whizbang wrote: »

OP, you need to pull out all of the Bulbs in you bathroom, and figure out how they are connected. Transformers are usually left lying around in the ceiling, will pull out with the fitting.
Take out the transformer(s) and check the load rating on the label, post it up here.

Most often these are each 50Watt bulb connected to its own transformer, so you have as many transformers as lights.
Sometimes there are multiple bulbs connected to a single transformer. Probably 20Watt bulbs.

In the first case, chances are that the transformers will not work properly with just a single 5watt Led bulb.
- You could replace each fitting with a mains GU10 easily, but not recommended in bathroom.
- You could rewire all the fittings into a single transformer, like case 2.

In the second case, you just replace the bulbs, chances are transformer will work well with multiple Led bulbs.

Thanks for this. So are GU5.3 specifically recommended for bathrooms?

There are other bathrooms in the house and they all have GU 10. This is probably the main one (at least it has an electric shower).

alias no.9 · 28-06-2020 12:39am

If the transformers are not suitable for LED's, I'd just recommend replacing with GU10 fittings and LED's rather than upgrading the transformers and fitting GU5.3 LED's. The other consideration is dimmer switches, if you have dimmers, these will probably need to be upgraded for LED's and also the LED;s themselves need to be dimmable.

CarPark2 · 28-06-2020 12:33pm

alias no.9 wrote: »

If the transformers are not suitable for LED's, I'd just recommend replacing with GU10 fittings and LED's rather than upgrading the transformers and fitting GU5.3 LED's. The other consideration is dimmer switches, if you have dimmers, these will probably need to be upgraded for LED's and also the LED;s themselves need to be dimmable.

Thanks. We don’t have dimmers.

Lex Luthor · 29-06-2020 7:48am

alias no.9 wrote: »

If the transformers are not suitable for LED's, I'd just recommend replacing with GU10 fittings and LED's rather than upgrading the transformers and fitting GU5.3 LED's. The other consideration is dimmer switches, if you have dimmers, these will probably need to be upgraded for LED's and also the LED;s themselves need to be dimmable.

This is what I did. I had issues with trafos in the past , the odd one failed. I just decided for one less device to have in attic to fail

In relation to my post above about heat, I was referring to the bulbs but the trafos also have some heat

I now have all my gu10’s under hoods

CarPark2 · 29-06-2020 10:34am

Lex Luthor wrote: »

This is what I did. I had issues with trafos in the past , the odd one failed. I just decided for one less device to have in attic to fail

In relation to my post above about heat, I was referring to the bulbs but the trafos also have some heat

I now have all my gu10’s under hoods

Any link for where you bought the hoods?
If you have the hoods, does that mean that you can cover with insulation, at the normal thickness in the attic?

CarPark2 · 29-06-2020 6:27pm

Thanks for all the responses. I appreciate the help.

OK, so below is a pic of the setup in the attic:

The hole is where the light fitting goes (it is currently hanging down in the bathroom as i removed the bulb in order to figure out what it is.

So it seems to be a transformer for each light fitting. Transformer has a 12V output.
Awkwardly, there are four light fittings in the bathroom and one of them is under floorboards in the attic.
The floorboards are large OSB boards and nailed on, with the nails driven in deep. It doesn't look like they will be easy to get up.

So my questions:
1. Based on the transformer in the pic, will it not be possible to just change the halogens for LEDs?
2. Is it OK to have GU-10s in a bathroom - a post above seemed to suggest that they weren't safe for bathrooms (although all of the other bathrooms in the house have GU10s).
3. I saw online about needing IP65 in a bathroom - is that the bulb holder or the bulb?
4. I presume that this is a job for an electrician, given that it is electricity in a bathroom?

Thanks.

whizbang · 06-07-2020 11:49pm

Although there's nothing specifically written on that transformer, Its almost certain it has a minimum load specified to operate properly.
It means if there isn't enough power drawn out of the transformer, it cant control the output, and shuts off, and then repeats this cycle, causing flickering, dimming, pulsing or just nothing..
Quite often the minimum is listed at 20Watts, so 4 x 5W leds should work on 1 transformer., but not always.

I will leave the electricians to comment on the bathroom safety aspect..

CarPark2 · 08-07-2020 11:29am

whizbang wrote: »

Although there's nothing specifically written on that transformer, Its almost certain it has a minimum load specified to operate properly.
It means if there isn't enough power drawn out of the transformer, it cant control the output, and shuts off, and then repeats this cycle, causing flickering, dimming, pulsing or just nothing..
Quite often the minimum is listed at 20Watts, so 4 x 5W leds should work on 1 transformer., but not always.

I will leave the electricians to comment on the bathroom safety aspect..

Thanks.
There is a separate transformer attached to each fitting, so i guess it will not work then.
My inclination is to get an electrician to replace the whole set up with GU10s.

Lex Luthor · 10-07-2020 7:23am

CarPark2 wrote: »

Any link for where you bought the hoods?
If you have the hoods, does that mean that you can cover with insulation, at the normal thickness in the attic?

Barrett’s Maynooth
About €9ea

You can cover with insulation

Buyingcar2012 · 11-07-2020 1:01pm

I’m planning to do the same - replace MR16/GU5.3 Halogen with Philips HUE GU 10.

I’ve attached a picture of a fitting of what I plan to buy.

So basically remove the old transformer and GU5 fitting and connect the mains wiring to the junction box of the attached fitting?

Is that all I’ll need to do?

Replacing GU5.3 Halogen with LED

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