Why does a bulb in my light fixture keep burning out?

Question

I have a relatively new (3 year old) 3-bulb light fixture. Lately, I have had problems with bulbs in one particular socket burning out very quickly. It's rated for 100-watt bulbs, but I've been using 75-watts. At one point I even switched to expensive compact flourescent bulbs, but the one in that particular socket burned out within a week, as did the second one I installed in its place. Bulbs in the other sockets seem so far to have a normal lifespan.

What is a likely cause for this, and how can I fix it? The fixture was just expensive enough that I don't want to replace it, but not quite valuable enough to warrant having it repaired professionally. I'm hoping there is some easy, obvious fix that I can do myself. Thanks!

Answer 1

Bulbs that are exposed to the air cool rapidly upon shutdown and destroy the metal to glass seal at the bottom. When that seal is broken, air enters, and the bulb then burns out.

Bulbs that are in enclosed fixtures last for years of usage, even switching them on and off several times a day, that is because these bulbs do not experience that rapid thermal change which destroys that glass to metal seal at the bottom end of the bulb.

You most probably have an open type fixture, so in your case the exposed bulb is the reason.

Point also to be made, is that Your fixtures socket for the bulb probably has a low "mass" right where the bulb screws into the fixture. This low mass or weight here allows that area to cool rapidly on shutoff and with that mass the lower end of the bulb also cools rapidly and destroys that glass metal seal. The old fixtures, had a very heavy mounting area compared to your new fixture. They got hotter down there and stayed hotter after shut off. They cooled down more slowly on shut off and heated less rapidly upon start up. This very point im making allowed the bulb to cool more slowly and heat less rapidly. That in itself contributed to the longer bulb life.

There is nothing wrong with wiring, grounds, voltage surges, and the like. None of this is contributing to any shortened bulb life.

In your case, examine that socket that is the culpret. Somehow that bulb is cooling down more rapidly on shut off at the metal to glass screw in connection. Perhaps that socket is of a lower mass. Perhaps a shield is missing from the socket. Anything that would make it cool more rapidily would cause this difference.

Answer 2

Light Bulb Keeps Burning Out

Answer 3

3 Bulb Light Fixture

Answer 4

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RE:
Why does a bulb in my light fixture keep burning out?
I have a relatively new (3 year old) 3-bulb light fixture. Lately, I have had problems with bulbs in one particular socket burning out very quickly. It's rated for 100-watt bulbs, but I've been using 75-watts. At one point I even switched to expensive compact flourescent bulbs, but the...

Answer 5

Hard to say. There is nol apperent reason for this to happen.
Unwire the fixture and take it down and physically inspect it. Are there any frayed wires and is the center contact of the problem socket pulled up enough to make firm contact with the bulb?

When a bulb blows next time, unscrew the bulb and screw it into another lamp or another socket in the same fixture. Just to be sure it is the bulb and not the socket.

Good luck

Answer 6

It's hard to tell others how to 'fix' things like this, especially when it comes to electricity.

It could be that there is a bit more current going thru this socket than the others, or maybe there is a little more voltage; either one could toast a bulb before its time. Anyway....it could be something about the socket itself, and I can't really tell you how to go about checking it because unless you know what you're doing it could harm you.

If you know a friend or someone that knows how to use a multimeter, or you are handy enough to do it yourself, it would be interesting to see what current and voltage is actually passing thru the socket. I installed dimmer switches on all my main room lighting. This way I can set the lighting to a lower level. When turning on a bulb it's MUCH easier on the filaments to handle the lower initial surge than the full blast of current right off the bat. Anyway....if you can get one installed you might lengthen the life of the bulbs in that socket, but if the problem comes from what I was suggesting a moment ago, then as soon as you turn the lights up to full, the bulb will be in the same conditions as it was before. It would probably have a longer life, but probably not as long as the others in the other sockets by comparison.

Sorry, but this is about all I can offer, unless you want to go to a higher rated bulb that can handle the punishment this socket is dishing out.

Answer 7

If it's hapening to just one bulb in a set of three its probably the socket. Try this. Make sure the power is off to the light at the breaker. Take that one bulb out and look at the contact in the bottom of the socket. If it looks like its pushed to far down pull it up a little. Sometimes when bulbs are tightened to much they can fatten the tab. The bulb then doesn't make good contact and the bulb can burn out quicker.

Answer 8

Everyone has covered a variety of electrical issues already.

How about mechanical? Is this particular fixture attached near a door or some other source of impact, shock or vibration, that the others are further from? I'm thinking slamming doors, well pump, fridge door slamming, kids playing ball, that kind of thing. Shock and vibration will quickly ruin incandescent bulbs. (Not sure about those compact fluorescent ones and impact as I have only recently begun using them.)

Answer 9

You have a bad wire in the circuit leading to that bulb...it "shorts" to interrupt power that might otherwise cause a fire. If you don't feel like having someone fix it, and you're not up it effecting repairs yourself, just replace the entire housing in the fixture. Sometimes that's a less expensive option.

Answer 10

It more than likely has a short in the wiring. Who ever hooked up your new fixture, probably you, missed something. I'd disconnect it. Make sure it's all secure. It's probably loose wiring or you got old wiring through your house that's why it's shorting.