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Will energy saving light bulbs burn my house down?
March 27, 2007 2:37 PM   Subscribe

What is normal when a compact flourescent bulb burns out?

Today I noticed that one of my CF's had burnt out, when it had been working yesterday. I didn't have another at hand to replace it with, so I didn't immediately remove it. My stepdaughter commented that she smelled burning rubber, but I didn't smell anything myself, and didn't connect it to the bulb. Several hours later, I had a nagging feeling that I should take out the bulb, although I didn't know why. When I went to remove the bulb, I smelled the burnt rubber my stepdaughter had been talking about, and realized that the bulb was oddly warm. (The light switch was on because it powered other lights in the room that still worked.) When I removed it, it looked like this. I've been using these type of bulbs for several years and have never seen one do this before. Is it a fault in the bulb itself, or could it be my wiring? Now I'm scared that if I hadn't just suddenly got a wild hair to remove the bulb, there could have been a fire, and I wonder if any of the many other CF's I have in the house could do the same thing.
posted by Shoeburyness to Home & Garden (19 answers total)
 
I saw a relevant news story on this recently.
posted by cardboard at 2:41 PM on March 27, 2007


OK, charring and a temporary bad smell I can live with, but are they supposed to still feel hot hours after they have burned out? That's what really concerns me. If it just got charred and smelly and then went cold, no big deal, but it seems to either get hot enough to still be quite warm several hours later, or to continue to generate a much larger than normal amount of heat until it is actually physically removed from the socket. That doesn't seem safe to me.
posted by Shoeburyness at 2:54 PM on March 27, 2007


Doesn't seem right to me either... Going by this page and this(Canadian, but still...), I think you should report it to your fire department who can pass the information on to the relevant agencies. But then it sounds from that news story like they're sending out an advisory not to worry about it... Still it wouldn't hurt to make a quick phone call would it?
posted by Morbuto at 3:09 PM on March 27, 2007


In order for a mercury vapor bulb (which all compact fluorescents are) to light up, something has to vaporize enough mercury to carry a current when you turn it on. In the case of your buib they use heat, it looks like, and when the mercury arc strikes, the heater is supposed to go off. When the mercury arc did not come on, it looks as if your bulb just kept heating and heating.

This would not have happened if the switch had been turned off, and it probably would not have ever gotten hot enough to cause a fire. It also probably did not release its mercury into your home; if the bulb had fractured, I think oxygen would have consumed the heating electrode immediately and it would never have heated up enough to char.

It does seem strange to me, however, that we are making such a big push for these bulbs with their burden of toxicity, when white LEDs, which are already at least twice as efficient, are only a few years away, if that.
posted by jamjam at 3:36 PM on March 27, 2007


I noticed something similar just the other day-- the warmth, not the burnt rubber. It does seem like shoddy design. Not to mention it hasn't been there ten years like the packages suggest (grumble, grumble).
posted by alexei at 3:50 PM on March 27, 2007


Well, crap. I didn't know the bulbs weren't supposed to be used in enclosed fixtures. That kills my idea of putting them in my kitchen, hallway, stairwell, and basement. I was planning on making the switch incrementally, but now I guess I won't. I only have two places with open fixtures, but lots with globes.
posted by Corky at 4:11 PM on March 27, 2007


May I ask the brand? I know that some of the crappy Chinese makes have taken a beating: Lights of America (example),and DuraLight/Commercial Electric (recall) have had safety issues and are not well-regarded for their quality.
posted by zek at 4:31 PM on March 27, 2007


It was a Sylvania.
posted by Shoeburyness at 5:05 PM on March 27, 2007


Yeah, as cardboard says, this has been getting some press in Canada in the last week. It's not unusual for CF bulbs to burn out by actually, well, burning out a little. Not sure about still being hot - it seems weird that it would still be drawing current to generate heat, and that is a little worrrying.

Not sure what brand it is, but my advice is to buy one of the better brands - Philips, Globe, Sylvania, probably also GE (though I've found their bulbs too big). Not only will you get better light (Philips in particular comes closest to reproducing the soft white light of an incandescent), you can have better confidence that the bulb isn't going to end its life funkily.

And, yes, don't use CF bulbs in enclosed fixtures. They're also best used standing up so the heat they generate doesn't warm up the ballast and reduce their life.
posted by Dasein at 5:14 PM on March 27, 2007


Well, crap, really should have previewed. Okay, try Philips or Globe in that case.
posted by Dasein at 5:14 PM on March 27, 2007


Well, crap. I didn't know the bulbs weren't supposed to be used in enclosed fixtures.

I think that's crap. Incandescent bulbs generate around four times more heat than fluorescents, so any place an incandescent goes, the equipvalent (light output) CF bulb can certainly go. I have had them in enclosed fixtures for years. And there are plenty of closed fixtures that are manufactured specifically for fluorescents, both the compact variety and the "circline" ones. Some CF bulbs, made for outdoor use, come with their own "enclosure." And they can go upside down just fine -- that little extra heat will not burn the ballast out. Nobody's house ever burned down because of a faulty CF bulb.
posted by beagle at 6:32 PM on March 27, 2007


I have 100 watt equivalents in large schoolhouse type glass globes, about 16 inches across. They've lasted for years in there. Maybe a small glass globe would build up more heat, and burn out faster.
posted by jjj606 at 6:32 PM on March 27, 2007


This all sounds strangely like a conspiracy against Gore's call for todos los personas to use said lightbulbs in order to save the planet. Shoeburyness, are you with the Agency?
posted by Oddly at 6:47 PM on March 27, 2007


beagle, it's absolutely not crap - just Google a little bit. The reason is that the ballast in CF bulbs is especially sensitive to the (lower) heat that even a CF bulb puts out. That's also why they are best used standing up - so the heat dissipates away from the ballast. Yes, they can go upside down, but it shortens their life.

There are some that are built for outside use, but those are, as you say, specially built for outdoor use. You're right that there's not a lot to worry about, though, in terms of them causing a fire.
posted by Dasein at 6:47 PM on March 27, 2007


I think that if you continue to provide power to any broken device you risk a fire. You should have removed it if you weren't going to leave it off.
posted by krisjohn at 6:58 PM on March 27, 2007


i used to work for a company that imported our own brand of CFs. I typed up the specs on the packaging i designed, and it definately said No enclosures. No dimmers.

they do get really hot, and especially the electronics of the ballast...if the quality control is off on that part they won't last as long and can--like any faulty electronic device--cause fires.

Any lightbulb is going to create heat though...a friend has a tactical LED flashlight that could cook meat.
posted by th3ph17 at 8:33 PM on March 27, 2007


krisjohn's advice is right on.

The fire hazard presented by the different kinds of bulbs are so completely different, it is very hard to compare. For one, any fire hazard due to incandescents is related to the fixture and the user, never the bulb, and this isn't the case with CF. It is made much worse because of the large number of models and manufacturers, which all have to be safety tested independently.

I guess that you should be about as worried about fire as you would be with any other electronic device in your home - the same safety agencies are doing the testing on all of them, and to relatively similar standards.
Ya, it feels like a lame answer to me as well, but it is the best I can do.

There was a recent question that relates closely to the enclosed fixture issue: Do compact fluorescents change maximum wattage allowed?
posted by Chuckles at 8:39 PM on March 27, 2007


Nobody's house ever burned down because of a faulty CF bulb.

I saw the story on CBC news when it ran on TV and actually there has been exactly one house fire attributed to a bad CF bulb. The specific bulb model that started the fire had already been recalled when the fire occured though.
posted by GuyZero at 5:40 AM on March 28, 2007


I typed up the specs on the packaging i designed, and it definately said No enclosures.

OK, so I went to my stash of CFBs and read everything on the packaging. Not one of them said anything to the effect of not "No enclosures". Show me one.
posted by beagle at 4:08 PM on March 28, 2007


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