Just replaced some MR16 50w halogens, that where installed professionally about 11 years ago, with GU10 LEDs.
A couple of the lights had failed and I suspected blown transformers but I wasn’t expecting to find the cable connectors melted through heat rising from the halogens!!
The fittings hadn’t been bodged, the connector was in its proper place on the fitting – this just happened to be above the lamp and therefore in the warm air flow rising from the bulb. It’s scary finding stuff like this in the roof 😯

Overheated and very brittle chocky block

Melted chocky block by Metal-Chicken, on Flickr

that must be from heat caused by a poor connection surely?

50W halogens do put out a lot of heat though and I would always get shot of them for something else.

I would like to see some good comparison images of the current LED replacements.

The connections on the top pic where just fine, it had just slow-cooked!

I mean that bottom one. Properly melted.

Funny coincidence…. I just replaced some fried chocolate block on a 12v halogen yesterday. Looked just like yours…. Doesn’t seem to happen with 240v?

Just curious – would it be a big current flowing through that connector?

If its 12v 50w then it’ll be 4 amps. That looks like 3a choccy. Its generally OK with higher currents but it would need to be well fitted.

240v will be much lower current.

These need a large space around them to avoid them overheating. The electrician on one of my projects just stuffed them in the smallest hole in the insulation he could make, Fortunately I realised there was going to be a problem, and had to massively increase the void spaces in the insulation, thus causing cold spots in the roof 🙁

I would not use them again. There is a lot to be said for simple ceiling rose and added mobile light where you need it ( unless you are prepared to spend a lot of money on lighting solutions)

50 watt halogen here with laser thermometer is between 60-80deg c r50s and gu10

4.5 watt 240 v gu10s leds come in at 25degree c so on the same thermometer and having been on same length of time as the r50s and dont seem to be any hotter behind – i lifted the floor boards upstairs and checked ( i lie….. My floor boards were up already ;))

So watch your insulation if your fitting spots

Righog – you can get blankets and buckets to go over top of your light to isolate heat

I put off cuts of alloy cylinder barrels over mine in the attic. Long enough to go throughout the rockwool.

Just pulling my car apart now for cylinder barrels. Good call…. 😉

Upturned clay flower pots work well, they even have the hole in the top for cables

Does glasswool burn then?

globalti – Member
Does glasswool burn then?

probably not but the problem is it traps ( insulates ) the heat produced and the light fittings and wire burn. My insulation was kingspan but the roof was made of wood.

Trail rat was correct there are hoods available ( I have these fitted ) these maintain the fire rating of the roof with the lights fitted and these where required by the building inspector.

Dowlighter fire shield

Led’s must be better in all respects, non ?

I’ve still not found LEDs that look nice when dimmed, but otherwise, yes.

I used to see this all the time when i was a service engineer for a major supermarket
On the food warmers in the cafes you have a bank of 4 or 5 halogen lights,1 or all of
them would stop working and the wiring would have just destroyed itself with the heat,
they fitted ceramic connector blocks instead of plastic but the wiring despite being sleeved
in fibreglass would turn black and crumble away over time.

There must be many millions of these now in houses, shops and offices around the world but there still hasn’t been a Daily Mail scandal exposé of the hidden danger lurking in our ceilings so I still feel reasonably safe….

not had chance to read the full thread, but I think you can buy different types of downlighters, some specifically direct the heat down with a metal backing to reduce upwards heat.

I thought all new downlighters had to be fire rated? I know whe had to have them fitted with heat & noise?! shields when our extension was built 3 years ago – Building Regs demanded it & I think it’s written into the Part P rules on electrical installations.

IIRC the Electrical Safety Council offer specific guidance & literature on them.

Found it

http://www.mygreenlighting.co.uk/replacement_bulbs/spot_bulbs/gu10_type_twist_and_lock/gu10_bulbs/401.html

“This is a dichroic lamp that is designed to reflect the heat backwards into the light fitting and the light forwards. Make sure that you choose the right sort of lamp for your fitting. Aluminium lamps reflect the heat forward out of the fitting. See the related products tab for more options.”

http://www.mygreenlighting.co.uk/replacement_bulbs/spot_bulbs/gu10_type_twist_and_lock/gu10_bulbs/864.html

“This is an aluminium reflector lamp that is designed to reflect the heat forwards away from the light fitting. Make sure that you choose the right sort of lamp for your fitting. Dichroic lamps reflect the heat backwards in the opposite direction to the light. See the related products tab for more options.”

I always buy the aluminium type for all my fittings

not had chance to read the full thread

There are less than 20 posts!

side affect of looking busy at work LOL 😆

Should’ve been “fewer” than 20 posts too. I’m annoyed at myself.

Anyway gents – back to death lights.