Need some advice and fast

[wade88]

Morning everyone,

Had my first emergecny call out last night at 9.30pm...rather annoying, but a families downlighter had caught fire with three kids asleep upstairs and they were in rather a flap about it.

Upon arrival to the house and giving the fitting an inspection it was apparent straight away that it had obviously over heater and got very very hot subsequently causing it to burn. i could see no transformer present for that fitting but i do believe downlighters can share transformers, maybe 3-4 per transformer? Without lifting up their carpets and floot boards and getting a good look at what had been done with them upon installation i could hardly make any conclusions from what i saw, so just made it safe and left seeing as i had limited gear with me and was pretty much in my pj's.

Can anyone throw me any ideas/reasons as to what may have caused this fire, and just some general info on downlighters as im writing a report to their landlord and want to get it all right.

Cheers guys

B

 

[KFH]

Have a look at the ESC (Electricity Safety Council) website do a search on downlighters,they have information on downlighters and overheating/fires.

 

[bugsy]

are they low voltage or mains voltage ( MR16 / GU10 )
in any case they could have overheated due to lack of ventilation, poor connections or poor installation this can only be determined through an inspection of the fittings, installation method and wiring

 

[wade88]

ah of course, i even posted a thread giving people the links to download those last week! haha

 

[wade88]

They were GU10's, and they had been covered in thermal insulation. they were fire rated fittings but im not sure if they were permitted to be covered in thermal insulation however. But as you say, i could hardly draw any conclusions from what i saw as i wasnt able to pull the floor boards up and have a proper look at the time. so i have just wirtten a letter making some recommendations to the letting agency to correct the issue and replace the light fitting.

All i could do at the time was to terminate the cable into a junction box and tape over the hole. I hope thats adequate

 

[Hawk81]

If they are GU10 they are mains and there is no transformer. The fire could be due to the insulation or a bad connection of the lamp holder was not making a great connection.

 

[RWJ]

They were GU10's, and they had been covered in thermal insulation. they were fire rated fittings but im not sure if they were permitted to be covered in thermal insulation however.

GU10's Thermal Insulation...... There you go that's your answer

Fire rated means they will withstand a fire for the same amount of time as the plaster board they're fitted to (you have different time ratings for different plaster boards. Do a search, I'm sure it's been covered a few times)

The only down lighters I've ever seen that you can cover are NEW expensive LED fittings specifically designed to be covered.

 

[Hawk81]

GU10's Thermal Insulation...... There you go that's your answer

Fire rated means they will withstand a fire for the same amount of time as the plaster board they're fitted to (you have different time ratings for different plaster boards. Do a search, I'm sure it's been covered a few times)

The only down lighters I've ever seen you can cover are NEW expensive LED fittings.

I don't think its good to assume that the fire was just down to the insulation, there are other possibilties as I have already stated.

 

[RWJ]

I don't think its good to assume that the fire was just down to the insulation, there are other possibilties as I have already stated.

It's a pretty good starting point in my experience!
Also what type of Gu10 lamps...... Cheap ones that don't throw as much heat forward???

 

[Paul.M]

Don't rule out a combination of 2 or more things. Insulation needs to be min 100mm away from the fitting and if you have a bad connection or a cheap manufactures part that overheats you can get a fire.

The below picture is from my own bathroom. I've completely gutted it out and started from scratch and installed 5 x mr16 down lights. One light started to flicker, take a look and what did I find

cheap connection block melted. No insulation, well ventilated and installed by my self so I know it is done perfectly. If that block was covered with insulation who knows what could have happened? Also I looked at it on the first sign of it flickering, most house holders wouldn't and that could lead to more heat then turning into a fire. I would ask the customer if it flickered at all in the days/weeks running up to the fire.

 

[Hawk81]

It's a pretty good starting point in my experience!
Also what type of Gu10 lamps...... Cheap ones that don't throw as much heat forward???

Agreed it is a good starting point but that's not what you said. You said it was the reason

 

[wade88]

Well the estate agents have just called me and asked me to carry out a full inspection of the entire proeprty as they have had numerous issues across the house already. So ill let you know. i believe they were tungsten lamps which can climb to around 200 degrees anyway, i know that my flat is pretty much heated from out down lighters, we have never had the heating on once since ive been there! They were surrounded by rock wool and there was no ventilation at all. the connections were still in tact and they appeared to be ok, but there was scorching around the bayonnet fitting. I forget to check for the thermal insulation "ok" symbol, the upside down triangle with the F in with a little "hat" on, but clearly they wernt deisnged to be covered in such a quantity of insulation.

Ok so that clears up the transformer issue, are GU10's just linked together and fed from the one cable then? the MCB was a 10amp and it fed approximately 15-20 lights downstairs. if they are mains powered and there is no step down tranformer present i am to assume they are 230v then

 

[wade88]

The block was actually a heat resistant one, you know the brown jobs, 500v ones or whatever they are. so there was no damage to that, im regretting no taking any photos now but i literally ran out my house to go and see them and only had limited things but the majority of the damage had occured where the cables had been terminated into the connector about an inch back from the block. the earth had even got so brittle from the heat it had snapped clean away and the neautral soon followed as soon as i touched it.

 

[Hawk81]

Sounds like it was heating at the connection. The insulation probably had nothing to do with this although I would still want it removed from being on top of the lights.

 

[wade88]

Sounds like it was heating at the connection. The insulation probably had nothing to do with this although I would still want it removed from being on top of the lights.

What would be the likely cause of over heating at the connection then? Wrong type of bulb?