Electrical Question

Fawteen · Mar 3, 2010

Okay, first, I know the obvious answer: It's because I'm not a Licensed Master Electrician that charges $75 an hour, learned everything I know at the feet of Thomas Edison and Charles Steinmetz and has memorized the National Electric Code of every country in the Free World. But besides that...

WHY would a two-socket light fixture ALWAYS burn the same bulb out? Doesn't matter, either Those Horrible, Global Warming Causing, Wasteful, Kitten Killing, Right Wing Christian Conservative Incandescents or the Warm, Fuzzy, Eco Friendly, Save the Whale's Children, Rainbow Coalition, Kumbaya CFL's, neither will last more than about 30 days, and it's ALWAYS the same socket.

I've checked to make sure one of the sockets didn't have neutral and hot reversed, and voltage is within acceptable limits.

WTF?

CWL · Mar 3, 2010

Maybe a bad connection where the bulb bottoms out in the socket??

Fawteen · Mar 3, 2010

Inspected visually and electrically (resistance check) no problem there. Also made sure the bulb was seated snugly.

keh · Mar 3, 2010

I'm less electrically knowledgeable probably than anyone on here, but I would think about a loose connection somewhere in the fixture, maybe even a invisible break in the wireing somewhere under the insulation.

KEH

Stuart · Mar 3, 2010

Because you have two light bulbs that produce more heat. I have the same problem in my basement, I have a two socket adapter screwed into one socket. It usually does this if I have 100 watt bulbs in, doesnt do it when I have 60 watt bulbs in. Yeah I know a 60 watt bulb will last longer but a 100 watt bulbs should last a month. I think it is because there is more heat there.

rbel · Mar 3, 2010

Bingo

No good way to check for this short of replacement

Fawteen · Mar 3, 2010

This is designed as a two-socket fixture, rated for 60 watt incandescents. I have 30 watt CFLs in it, so I don't think heat is the issue. Plus, it's ALWAYS the same side of the fixture that burns the bulb out.

Fawteen · Mar 3, 2010

It ohms out the same, but I suppose it might be a physical restriction keeping the bulb from seating properly.

First thing so far that seems logical in light (sorry...) of the checks I've made.

Thanks.

phil25 · Mar 3, 2010

Just a thought but can you get a total fixture resistance[ identical bulbs in] on the supply side and then sepaerate the two sockets, and check the resitance per socket compared to total fixture exsistance. Being a parallel circuit things should work out math wise, but there will be decimal place differences between bulbs and wire and loose socket rivet connections, hope it helps.
simple problem but can sure be a pita.

Richard H. · Mar 3, 2010

Stop using the suspect side just leave the spent bub in it and put a 60 cfl in the good side.

Stephen Atkins · Mar 3, 2010

After about a week switch bulbs.

steveormary

sotxbill · Mar 3, 2010

either arcing or heat...

PJH · Mar 3, 2010

A recurring coincidence - which I think may be an oxymoron. Our kitchen ceiling fan/light does that too. Something to lay in bed and wonder about. It makes me sure to turn the light out when no one is going to be around.

Let us know when you figger it out.

Paul

Kruse · Mar 3, 2010

I have a bathroom medicine cabinet with four exposed bulbs on the top side. I had some incandescents in there and each bulb would last about a month, no more. With four bulbs burning out a month, it really added up. I now have the curly fluorescents in there and they do last a lot longer, but if a bulb needs replacing, it's still a bulb in the medicine cabinet that will probably need replacing.
The only thing I can figure out is that there is a washing machine on the other side of the wall and when it sometimes goes into the spin cycle, it will shake that area. That's the only thing I can think of that is blowing the bulbs in this area of my house.

teddy52food · Mar 3, 2010

I had a problem with the basement light bulbs that didn't seem to last long. The electrician said it could be from a loose ground. He went to the main breaker box & loosened then tightened the ground connections. It seems to be better now.

Leyland-270 · Mar 3, 2010

Had a similar issue in my shop office during the winter months. The fixtures I had were the ones with a square glass diffuser open on all sides. During the winter the bulb (in a two light fixture) closest to the door would burn out from the temp change of opening the door. I finally figured it out when summer rolled around and that bulb quit burning out and the one near the A/C vent started burning out on a weekly basis.

So my question is this, Is it near a vent or in a place it can catch a draft. If not there is definitely a bad connection some place. Since it is always the same bulb in the fixture I would guess it is in the fixture, and should be replaced.

Jaden · Mar 3, 2010

I had a similar problem. Turned out the center connection was just a little low to firmly contact the bulb when fully screwed in. I pulled it out a little and the problem went away. (The center contact was blackened from the heat build-up)

Sid · Mar 3, 2010

"WHY would a two-socket light fixture ALWAYS burn the same bulb out?" I have no idea. I didn't know you could burn the same bulb out more than once.

Fawteen · Mar 3, 2010

Arrrrrrrrrrrr. Humor.

olddog · Mar 3, 2010

Check resistance from the white (Neu) wire to the edison screw shell in the fixture.
Had the same problem in our bathroom. Two chinee fixtures installed same time 20 years ago, on the same circuit. Same watt bulbs. For a while predicted that if one burned out, the other would follow in a month. Last coupla years, the one burned out much faster than the other.
Finally, it started blinking and buzzing.
Installed a new fixture and really had a look at the old unit. The neutral wire was soldered to a rivet, which went thru a bakelite piece and then thru the screw shell for neutral. Changing the bulbs had loosened the rivet connection and it was arcing around the rivet.

JMOR · Mar 3, 2010

(quoted from post at 17:37:20 03/03/10) Arrrrrrrrrrrr. Humor.

contend that you should look at factors outside the electrical arena, because such things as bad grounds, loose connections, reversed hot/neutral(???makes no sense at all!!), should only serve to reduce voltage & prolong bulb life, not shorten it. An exception might be if the connection were so bad that the light actually went on & off, as in repeatedly switching on & off, where the 10X cold inrush current hurts the bulb life. Vibration, difference in rigidity of mount, heat caused by air flow differences, proximity of surroundings, etc. I didn't include high resistance connections to the bulb, because if it were so bad as to generate significant heat above & beyond the filament itself, the socket/wires/bulb base should be burned/charred & visible to the eye and likely flickering or dim light.
My 2 cents.

buickanddeere · Mar 3, 2010

If tightening a bare ground wire in a panel solves a lamp failure problem. Shut the electrical service off and have everything checked by a capable electrician.

Cas · Mar 3, 2010

Probably a cheap chinese fixture. A month ago
I went to Lowes to buy a kitchen fixture. Looked
at every fixture they had and they were all made
in China. I think I would go buy another Chinese
fixture and add to our insurmountable trade
deficit.

gregk · Mar 3, 2010

I would look for a loose connection in the socket or just replace it as they are cheap. Also the whole socket could be loose and the vibration could be making it go out. Remember the lower the voltage the higher the amps, and the more heat, which means shorter bulb life.

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