Bad Transformer Spot Light in Loft

[Dundee_Stokie]

I have some spot lights in a small ensuite bathroom, and they regularly go out then come back on shortly after, like a dimming effect.

I think I have found the root cause of this, I went up into the loft, peeled back the insulation above the bathroom and there was a fried dimming transformer unit on a spot light - How do I fix this ? (also, one thing to note, the bathroom doesnt have a dimmer switch, its a standard on/off, so do these need to be transformer lights ?)


A good unit:

The bad one:

 

[securespark]

You pin-pointed the problem in a few words:

"peeled back the insulation"

There should not be any above light fittings that are installed like that.

Think about it:

what does loft insulation do?

how much heat do the transformers and dichroic lamps produce?

what does heat do?

 

[PrenticeBoyofDerry]

As stated above by securesparks; the transformer should not be covered in thermal insulation, they should be at least 150mm clearance all the way around, to allow the heat to dissipate.
Just because there is no dimmer switch operating the lights has no bearing on whether transformers should or should not be installed, your lamps will be rated at 12V that's why you need the transformers.

 

[Dundee_Stokie]

Loft insulation keeps things warm ?

Transformer lights generate alot of heat ?

Heat burns things ! am I right ?

Righto, the lights are 100% definatley lying underneath and in direct contact with loft insulation. How do I correct this ?

 

[NewOrder]

Dare I say remove the downlights and replace with a proper fitting?

It looks like the wiring to the transformers is fried too, so you will probably need to find the original junction where the original fitting was wired and then put in a new cable from there.

The transformers are step down transformers, run those lights without one and you will have plenty of smoke and probably lots of glass every where.

The obvious answer would be once the wires and fittings are replaced is to remove the insulation but I am not sure what the building regs say about that. Either way a shocking DIY job (hopefully) and installed by somebody with no common sense.

 

[PrenticeBoyofDerry]

The fittings look fire rated, could you please confirm.
Your transformers need to be clear of the insulation, as this looks like an accessible loft area, the most sensible thing would be to fit them securely above the insulation.
There is also the possibility you have had rodents nibbling at the cables, on your first picture the heat resistant sleeving looks to have been got at.

 

[westie101]

Hang on, the boxes shown in the first pics are not transformers, merely insulated units with a chocolate block inside. Though heat is probably the cause it will only be heat from the lamp.

If they are 12V the transformer(s) must be seperate

 

[NewOrder]

Hang on, the boxes shown in the first pics are not transformers, merely insulated units with a chocolate block inside. Though heat is probably the cause it will only be heat from the lamp.

If they are 12V the transformer(s) must be seperate

Good point, in fact looking closely it is very obvious I missed it as my eyes where drawn to all the burning.

 

[PrenticeBoyofDerry]

the white cable in picture one, suggest tranys!

 

[westie101]

The grey cable with white cores makes me go ????

 

[PrenticeBoyofDerry]

I think we need a little clarification from the OP!

 

[Dundee_Stokie]

What claification do you need ? I am not an electrician, all I see is whats on the photos, I would however like to attempt to fix this myself.

 

[westie101]

Take a look at one of the bulbs, is there a voltage marked on it?
If not take a photo so we can see what type of terminals it has.

 

[PrenticeBoyofDerry]

What claification do you need ? I am not an electrician

and we are not in your loft or bathroom to see what is what, so a little help would be appreciated!
And a picture of the transformers you mentioned, would be nice!

 

[securespark]

I would guess SELV. THe top pic has a fitting fed by a secondary output cable and a T&E runs off to a second fitting, so the transformers are probably cylindrical 105VA type, such as this:

http://www.tlc-direct.co.uk/Products/IBET105D.html

WF have a similar one as well.

BTW, the SELV lampholder in the first pic has the insulation falling off.