What bad thing will happen?

[frank70]

As an engineer friend of mine used to say when a software or specification issue was discovered - "What bad thing will happen?" I ask this regarding the admonition on various LED bulbs (such as the "Basic Bulb", the "Bright Stick", or the CREE 1600 lumen) that effectively reads "Not for use in totally enclosed luminaries". Since that phraseology has a vaguely legal flavor to it, and because I have a couple of the CREE bulbs inside 10 inch globes, and because I have a number of CREE 800 lumen bulbs (which do not bear the phrase) inside totally enclosed fixtures, I need to ask the same question.

If used inside an enclosed fixture, to me there are only two bad things that can happen:
1) The bulb fails (or performs poorly) prematurely; -or-
2) The bulb can start a fire.

Given that some of the CREE 800 lumen bulbs have started to occasionally flash or flicker after a year or so in service (and one failed totally, replaced under 10 year warranty), I'm willing to live with 1. I'm NOT willing to live with 2!

So is it a lifetime issue or a safety issue? Am I asking for trouble, or just a bulb dead before its time.

I see that the Bright Sticks have an internal fuse, so I'm hoping a UL rating precludes 2.

 

[amd20x6]

My understanding is that the lifetime will be decreased. If the electrolytic capacitor(s) don't fail early and take the bulb with it, the LEDs will get dimmer before they would have otherwise.

If it were a non-UL bulb in an enclosed fixture (no fuse) I could see certain failures causing a fire. Don't buy random crap on Ebay and you should be fine.

 

[more_vampires]

Don't buy random crap on Ebay and you should be fine.

Solid advise.

Another consideration with HOME LIGHTING IN YOUR HOUSE THAT CAN BURN DOWN is that a circuit for that light should be connected to a parallel circuit where the total wattage of stuff on that wire does not exceed the rating of the circuit breaker in the main circuit breaker box for the house.

This way, when your device shorts itself, it does not cause an electrical fire but instead simply flips the breaker at the box. Two flips in a row? Check the circuit, stop trying to reset the breaker. This is like the logical fallacy of replacing a fuse with a bigger fuse so it will stop blowing, rather than fixing the issue causing the failed fuse in the first place.

Sounds weird to say, but hazardous material becomes even more hazardous with the presence of an auxillary threat, such as an auxiliary electrical fire. It has a strong tendency to make safe stuff dangerous, fast.

 

[FRITZHID]

Idk.... I've run into more than several occasions where cfls in inclosed fixtures failed catastrophically.... 2 causes fires.
Being the curious type, I of course dismantled them to investigate. Caps were the higher failures but rectifiers and transistors both caused some intense heat and damage. And these were common use bulbs from Lowes & HD.
I can't imagine the electronics in the newer LEDs is much better.
I've been sceptical with new tech for years now, espc with the influx of Chinese crap and knockoffs that find their way into everything. Even small nightlights have smoked out on me.
I'm getting more and more into building my own lighting for my home. None of the "plug and play" upgrades available now. At least I KNOW what my builds can handle. No guessing. No wondering if some jerk off used substandard components, etc.
I just don't trust stuff I didn't build anymore. Call me old-school but hands on just seems safer these days.

 

[Steve K]

<..snip..>
I'm getting more and more into building my own lighting for my home. None of the "plug and play" upgrades available now. At least I KNOW what my builds can handle. No guessing. No wondering if some jerk off used substandard components, etc.
I just don't trust stuff I didn't build anymore. Call me old-school but hands on just seems safer these days.

For the stuff that I build, I try to house the electronics in a full metal container, with glass used to let the light out. The goal is to be reasonably sure that if any electronic component goes "poof", then the smoke and flames will likely stay contained.

I do feel somewhat reassured by having the required UL and other logos on the commercial lights that I purchase, and I only buy known brands at local stores. Still..... stuff does happen. I had one CFL that failed due to an overheated transistor. Fortunately, it was mounted in the bottom of the board, and when the solder got hot enough to turn liquid, the transistor fell out! Now that's what I call good planning!

 

[SemiMan]

For the stuff that I build, I try to house the electronics in a full metal container, with glass used to let the light out. The goal is to be reasonably sure that if any electronic component goes "poof", then the smoke and flames will likely stay contained.

I do feel somewhat reassured by having the required UL and other logos on the commercial lights that I purchase, and I only buy known brands at local stores. Still..... stuff does happen. I had one CFL that failed due to an overheated transistor. Fortunately, it was mounted in the bottom of the board, and when the solder got hot enough to turn liquid, the transistor fell out! Now that's what I call good planning!

If you stick to UL (ETL, CSA, etc.) in North America, then you can be assured that all the AC connected will be contained in a enclosure that is flame retardant, minimum UL 5VA rating. If you buy non name imports, then buyer beware, and that includes cheap AC adapters, USB power supplies, battery chargers, etc.

 

[FRITZHID]

If you stick to UL (ETL, CSA, etc.) in North America, then you can be assured that all the AC connected will be contained in a enclosure that is flame retardant, minimum UL 5VA rating. If you buy non name imports, then buyer beware, and that includes cheap AC adapters, USB power supplies, battery chargers, etc.

Tell that to the tenets of the 2 apt buildings that burned due to UL LISTED BULBS INSTALLED IN UL LISTED FIXTURES INSTALLED BY LIC ELECTRICIANS! I trust UL as much as I trust China crap products. I'll stick to my own products that I KNOW won't flame out in my house, ty.

 

[mattheww50]

While I concur with the advice that you stick to ETL,CSA and UL listed products, the unfortunate reality is that these marks are increasingly being used fraudulently. I.E. the mark is applied to a product that does not, and never did (or could have) meet the requisite regulatory standards. Since I have some experience with these standards, I can frequently spot the fakes because there is something about them that would constitute an 'automatic' fail for regulatory approvals. For example one of my favorites is the polarized connector at the device, and supplied with a non-polarized line cord. That's an automatic 'fail' for UL, CSA and ETL. I think HKJ has seen a number of devices that fail (or would fail) what UL calls the 'Hi-POT' test (test for insulation between the line and ground/neutral)l because of inadequate physical separation between conductors).

Unfortunately you are now almost forced to stick to brand names purchased from established retailers, and even that isn't a guarantee that the UL/CSA/ETL listed products really are. It has become too profitable to fake it, and with the company in China, if your house burns down as a result, I wish you well in collecting anything from manufacturer (assuming that name hasn't been faked as well).

 

[Steve K]

If you stick to UL (ETL, CSA, etc.) in North America, then you can be assured that all the AC connected will be contained in a enclosure that is flame retardant, minimum UL 5VA rating. If you buy non name imports, then buyer beware, and that includes cheap AC adapters, USB power supplies, battery chargers, etc.

are the plastics used in housings all flame retardant? I hadn't considered it... and it seems like it would be hard to do (depending on the test conditions, I suppose).

The CFL that failed in my table lamp was labeled GE, with the UL mark. It should be a quality design, and it probably was. All kinds of stuff can fail, though, and validation testing will just find the most likely failure modes. I do wonder how benign the failure would have been if it was oriented horizontally in an enclosed fixture, where the transistor wouldn't have self-extracted itself from the board. An enclosed fixture should have help contain any fire... shouldn't it?
I've got a Flickr album for the dead CFL here:
https://www.flickr.com/photos/kurtsj00/sets/72157627065777555

 

[poiihy]

are the plastics used in housings all flame retardant? I hadn't considered it... and it seems like it would be hard to do (depending on the test conditions, I suppose).

The CFL that failed in my table lamp was labeled GE, with the UL mark. It should be a quality design, and it probably was. All kinds of stuff can fail, though, and validation testing will just find the most likely failure modes. I do wonder how benign the failure would have been if it was oriented horizontally in an enclosed fixture, where the transistor wouldn't have self-extracted itself from the board. An enclosed fixture should have help contain any fire... shouldn't it?
I've got a Flickr album for the dead CFL here:
https://www.flickr.com/photos/kurtsj00/sets/72157627065777555

Wow how interesting!

Why would a transistor in a CFL get hot enough to fail? Did it get hot just because the lamp was used in hot conditions for too long? Or was there a malfunction in the circuitry causing the transistor to become hot?

 

[Steve K]

Wow how interesting!

Why would a transistor in a CFL get hot enough to fail? Did it get hot just because the lamp was used in hot conditions for too long? Or was there a malfunction in the circuitry causing the transistor to become hot?

the CFL was being used in an ordinary table lamp, with no lack of ambient air at 75 degrees F (or so).
The photos don't show any other component with an obvious failure, so I don't know what caused the transistor to overheat. Maybe a bad solder joint that kept the transistor from turning on fully, thereby increasing the power dissipation?

I was just amazed that I heard a little "tink" when the light went out. Usually I associate that sound with the failure of the filament in an incandescent bulb, but in this case, it was the transistor falling out of the board and hitting the bottom of the bulb housing.

 

[RetroTechie]

Why would a transistor in a CFL get hot enough to fail?

Perhaps a better question: "what operating temperature, or how many on/off cycles are needed to make at least 1 component fail, over 6000 working hours?". Probably not that hot, or not that many on/off cycles... Remember plastic is a poor heat conductor, so you don't need much dissipation to have internal temps much higher than ambient air.

Sooner or later, something will give. And 6000 hrs isn't too bad considering some of the crap that's on the market today.

In this case, might have been a poor solder joint. Every on/off cycle makes it crack a tiny bit more, component weight pulls on the joint, solder need not completely melt but gets soft when bulbs runs hot enough, then (given enough time) the transistor leads slide out. All parts may even be fine, such that lamp would still work if transistor was soldered back in (in the correct orientation!).