Are LED Light Bulbs a Fire Risk

[mbohuntr]

I hate to correct anyone, but in reality the electronics driving the LESs are quite efficient and need little or no heat sinking. It is the LED that generates most of the heat. Typical LEDs have 15-20% luminous efficiency. So if you take the wattage of the light, 80-85% of that is dissipated as heat. Nearly all of the cooling requirements are for the LED(s).

paul

Not taking any offence, The heat sink encompasses the LED DRIVER containing the mip552 which is only rated for 75 deg. F. The driver in this light circuit is switching at 44khz. Power transistors can get VERY hot! An IGBT working as a variable frequency drive needs and is entombed in its own dedicated cooling system.

While I stated that the power transistor can get very hot and requires a heat sink, I never said it was a large heat source, only perhaps the hottest temperature wise, and the part that needs cooling to protect the LEDs as stated in the IEEE article.

http://m.eet.com/media/1124374/10640-figure_4.pdf
The Subtle Circuitry Behind LED Lighting - IEEE Spectrum

 

[hr3]

Finished changing bulbs for now . 18 60w and 9 65 w floods . Went from 1665 w total to 252 w total . A reduction of 1414 w . Got 6 more 60 w to go, but ran out of bulbs and a few odd shaped bulbs that I may not be able to find LED equivalents for .

One thing you might want to read the package they come in.. Lots of led bulbs aren't listed to be put in enclosed fixtures..

 

[RBLapham]

In January & February of last year I replaced every light bulb on the place with LEDs except the Liftmaster Garage Door Opener bulbs that didn't work with LEDs and the appliance bulbs (oven, refrigerator, microwave). Some were from Walmart, some from Lowes, some from Home Depot; none have failed yet.

Many LED bulbs generate Radio Frequency Interference RFI, Using a LED bulb on your door opener unit that generates RFI can disable a garage door opener when using a RF remote. Opener works fine if light out, does not work if light on. TRY ANOTHER LED BULB (different brand).
LED bulbs with the Energy Star ratings should not have RFI.
Another debated problem with LED's is as they switch (blink) at various speeds to generate the different colors like cool white, bright white, warm white etc - some people claim it makes them nauseous or dizzy. My wife is one of them. Again not all LED bulbs and only some people. Again the Energy Star approved should be better.

 

[k0ua]

Many LED bulbs generate Radio Frequency Interference RFI, Using a LED bulb on your door opener unit that generates RFI can disable a garage door opener when using a RF remote. Opener works fine if light out, does not work if light on. TRY ANOTHER LED BULB (different brand).
LED bulbs with the Energy Star ratings should not have RFI.
Another debated problem with LED's is as they switch (blink) at various speeds to generate the different colors like cool white, bright white, warm white etc - some people claim it makes them nauseous or dizzy. My wife is one of them. Again not all LED bulbs and only some people. Again the Energy Star approved should be better.

So far, I haven't detected any RFI from the Cree brand. See my thread about this below. I just put in 10 more yesterday.

http://www.tractorbynet.com/forums/related-topics/318587-rfi-cree-led-bulbs.html?highlight=

 

[95XL883]

I had one of the early LEDs in a puck light fail "catastrophically". The driver/electronics got so hot it burned a hole in the puck light. In the right situation, it might have been a fire hazard but where I had it, it wasn't a problem. I attribute the failure to an early design using very cheap parts. My uninformed opinion is they are a much less fire risk than incandescent bulbs. (While changing one once I discovered a prior owner had put in such high wattage bulbs he had cooked the wiring. I wound up replacing a number of fixtures, wiring and bulbs after that discovery.)

I have 12 can lights in our kitchen and laundry room with led floods. I would change out the whole house but I hate throwing working bulbs away. In other words, my uninformed, non-expert, clinging to my guns and religion (oh and my wife too; I really like her) is LEDs are much safer than incandescent lights.

 

[hr3]

Some good reading here on led bubs and they address enclosed fixtures too.. https://www.washingtonpost.com/news...aring-up-some-of-the-confusion-on-led-lights/

 

[sailorman]

Some good reading here on led bubs and they address enclosed fixtures too.. https://www.washingtonpost.com/news...aring-up-some-of-the-confusion-on-led-lights/

Interesting read . Thanks .

 

[k0ua]

The Cree 4 flow can be used in enclosed fixtures.

Search Results for cree 4 flow at The Home Depot

 

[techman]

Not taking any offence, The heat sink encompasses the LED DRIVER containing the mip552 which is only rated for 75 deg. F.

The best reference I can provide was a recent teardown article in Design World (I had to dig around to find it again):

Teardown: 60-W-equivalent LED bulbs

As you see the various models evaluated, you will note that none of them use discrete transistors. The driver is a self-contained IC, including the switching driver. In none of the lights are the ICs heatsinked, only the LEDs are.

Paul

 

[mbohuntr]

The best reference I can provide was a recent teardown article in Design World (I had to dig around to find it again):

Teardown: 60-W-equivalent LED bulbs

As you see the various models evaluated, you will note that none of them use discrete transistors. The driver is a self-contained IC, including the switching driver. In none of the lights are the ICs heatsinked, only the LEDs are.

Paul

I dug a little deeper and you are absolutely correct! I humbly apologize.
your facts are better than my memory.
I am also fascinated by the boost/buck configuration bulbs. I built a few joule thieves for giggles, but never thought about using them for oscillation.....