LED bulb

[JDB3]

Been a while since I have been on here. Was talking to a man today, that said he had bought a package of LED bulbs & put them in an enclosed fixture. Later he read on the box that they were not to be used in an "enclosed" fixture. Do that make LED bulbs with this warning? Is this because these particular LED bulbs put out more heat (for some reason) ? Thanks for replies

 

[Little Bill]

Several LED bulb mfg have bulbs that can't be in an enclosed fixture. You need to look for ones that say they can go in enclosed fixtures.

 

[hbiss]

You need to look for ones that say they can go in enclosed fixtures.

I have no idea why they are allowed to sell bulbs that cannot be used in enclosed fixtures. The purchaser shouldn't have to look at the package fine print to find that.

Furthermore, I've questioned this whole thing about not being for use in enclosed fixtures as to why. They don't get hot, none of them do. Certainly not like an incandescent. So really, I believe it's just a recommendation that cautions the user that using a particular bulb in an enclosed fixture MAY shorten the lifespan because the manufacturer uses bottom of the barrel components (like electrolytics) to keep the cost low.

-Hal

 

[tthh]

I always assumed it just meant a shorter life than advertised if used in an enclosure. In my personal experience I've put many in enclosures and some were rated that way and some not.

 

[Little Bill]

I have no idea why they are allowed to sell bulbs that cannot be used in enclosed fixtures. The purchaser shouldn't have to look at the package fine print to find that.

Furthermore, I've questioned this whole thing about not being for use in enclosed fixtures as to why. They don't get hot, none of them do. Certainly not like an incandescent. So really, I believe it's just a recommendation that cautions the user that using a particular bulb in an enclosed fixture MAY shorten the lifespan because the manufacturer uses bottom of the barrel components (like electrolytics) to keep the cost low.

-Hal

The base of the LED bulbs do get hot (some anyway) and they are almost too hot to handle. All the electronics are there and that's the fail point. I have seen some that were enclosed and did fail.

 

[hbiss]

The base of the LED bulbs do get hot (some anyway) and they are almost too hot to handle. All the electronics are there and that's the fail point.

If that's the case, then it would be the heat sinking ability or thermal mass of the socket the bulb is screwed into that would conduct the heat and dissipate it away. Air trapped in the fixture would have little effect unless the socket had heat sink fins.

-Hal

 

[hillbilly1]

LED’s don’t like heat, I’ve seen many highbays burn out due to poor heat sink design, so probably the same with the enclosed fixtures.

 

[GoldDigger]

If that's the case, then it would be the heat sinking ability or thermal mass of the socket the bulb is screwed into that would conduct the heat and dissipate it away. Air trapped in the fixture would have little effect unless the socket had heat sink fins.

-Hal

But light sockets in luminaires and other light fixtures are not generally designed to serve as heat sinks. They used to be designed to withstand the temperatures of incandescent bulb bases, not to conduct heat away.
By their very nature, incandescent bulbs had no components that could be adversely affected by temperatures as high as 100C. No consumer electronics components which are affordable for use in LED bulbs can withstand that sort of temperature.
And the heat rejection of the electronic ballast circuitry typically located in the base of an LED bulb is generally dependent on air circulation, and surrounding air temperatures reasonably close to ambient temperatures. In an enclosed fixture you might have neither.

 

[hbiss]

And the heat rejection of the electronic ballast circuitry typically located in the base of an LED bulb is generally dependent on air circulation, and surrounding air temperatures reasonably close to ambient temperatures. In an enclosed fixture you might have neither.

I doubt very much that there would be an appreciable difference in air circulation either way. It all goes back to making a decent product with a reasonable lifespan. Not using the cheapest components and design possible to make more money then put fine print on the box about not using it in an enclosed fixture as an excuse when it burns out after a few weeks. But what do you expect from China?

-Hal