What caused this fixture to catch on fire?

[Stopsignhank]

Here at work someone turned on this light fixture, heard a pop, saw sparks and then flames. They were able to unplug it and put out the fire. The fixture is good for 100 watts and had a 100 watt bulb in there. It is unknown how long the bulb was in there, meaning it is not a new bulb. The fixture normally hangs light bulb down.

I have an idea but I would like to hear other theories.

 

[BoomerD]

Electricity.

 

[Drako]

First picture not loading for me.

 

[Stopsignhank]

First picture not loading for me.

This is a better picture. Hopefully it loads.

 

[Drako]

Oh, I thought you had 4 images in the OP. Looks like an unloaded image icon above that first image.

 

[Stopsignhank]

No worries, the copped picture is better anyway.

 

[Humpy]

Tightening/loosening the bulb caused the socket to rotate over time, causing the wires to nearly cross where they terminate at the socket. An arc occurred when turning on the light and started a fire.

That's my guess.

 

[Ruptga]

 

[Stopsignhank]

So far we think aliens came down and tightened and loosened the bulb until the wires crossed. Then when Lee turned it on electricity caused it to catch on fire.

 

[sdifox]

Socket was spotty, leading to thermal buildup due to lowered conductivity. And then it arcs.

 

[Humpy]

So far we think aliens came down and tightened and loosened the bulb until the wires crossed. Then when Lee turned it on electricity caused it to catch on fire.

It was probably that dumbass Lee screwing with the bulb, not aliens.

 

[Stopsignhank]

I'm sorry, I don't speak Canadian. When you say spotty you mean it was dirty or it was bad?

There was definite thermal buildup. The fire could have had something to do with that.

My theory is the light might have been loose. Then when it was turned on it arced, kind like a spark plug. The guys say it took about 15 seconds to unplug so that would lead to the fire.

 

[Stopsignhank]

It was probably that dumbass Lee screwing with the bulb, not aliens.

Did I ever tell you about the time Lee got nitric acid on his leg and did not clean it off properly so he ended up with burns on his leg?

 

[Humpy]

Socket was spotty, leading to thermal buildup due to lowered conductivity. And then it arcs.

It looks like there is more damage behind the socket so that's where the fire started?

Edit: I think I'm a little disoriented in the closeups of which end of the fixture it's showing. Lee also takes bad pictures apparently.

 

[Humpy]

Did I ever tell you about the time Lee got nitric acid on his leg and did not clean it off properly so he ended up with burns on his leg?

Fuckin' Lee and his hi-jinks!

 

[drinkmorejava]

What is the weird black tab looking thing coming out of the middle conductor. Almost like it was some nonstandard 3-way socket. Put a regular bulb in there and you can short it out if the design is crappy enough.

 

[PottedMeat]

huh never seen a bulb socket with integrated heatsink

 

[sdifox]

I'm sorry, I don't speak Canadian. When you say spotty you mean it was dirty or it was bad?

There was definite thermal buildup. The fire could have had something to do with that.

My theory is the light might have been loose. Then when it was turned on it arced, kind like a spark plug. The guys say it took about 15 seconds to unplug so that would lead to the fire.

Spotty=flaky.

 

[JulesMaximus]

Fuckin' Lee and his hi-jinks!

He probably crossed the streams too. Never cross the streams!

 

[Red Squirrel]

That is definitely odd, and given that big heat sink, you'd think this would not have been an issue but clearly it was generating quite a lot of heat. My guess is an abnormally loose light bulb that happened to be tight just enough so that it works, it probably fused into place from corrotion, keeping it lit, but also creating a lot of low resistance points which eventually lead to a fire.

Just a wild guess though.

This was just an incandescent right? Or was it a LED or CFL? If it was one of those then it could have easily been a freak sporadic failure of the power supply electronics. They tend to use rather low quality parts in those with anticipation that they don't have to last all that long compared to other electronics.

CFL failures can be fairly dramatic. Best is when they pop and release all the mercury into the air. Yum.

 

[PottedMeat]

huh i guess i have seen these before - is it a machinist light?

http://www.mscdirect.com/product/details/85607281

 

[Humpy]

Seeing a picture of an intact light, my new guess that the switch failed first.

Since it's a super awesome 'murican made light I want to know if they will send out a new one for free.

Ask for Dave.

Moffatt Products Inc.
222 Cessna Street
WATERTOWN SD, 57201
UNITED STATES

customerservice@moffattproducts.com

 

[Stopsignhank]

That is the light. We have a lot of them at work. It is a incandescent bulb. In fact it was a rough duty bulb, so it is made a little more heavy duty than a regular bulb.

Oh and BTW, That fuck up Lee did not take the pictures, I did!!

 

[Charmonium]

What are all of those heat fins for? I have clip on lights with ceramic sockets that are rated for 300 watts I think and they don't have any kind of heat fins. That's just plain weird. Is this just a light or does it have some other function?

 

[Imp]

Jesus...

And maybe arcing or heat build-up from loose connection, crappy bulb, crappy socket.

Thank Jesus for LED bulbs that only use about 20W to produce the same lumens as a 100W incandescent and won't turn into a mercury bomb if it breaks like a CFL... but still manages to put out a ton of heat.