quote:Originally posted by posatyvo
I believe the ground wire was not connected properly.
jrishaw:
Light bulbs have hot and neutral, is there even a ground?
Mine seem to. There were three wires, one hot, one neutral and a little copper looking one that I just assumed was a ground/surge protection wire. I have been remodeling my house and all the lights I have fiddled with have had them. The only one that didn’t have one was the kitchen and that was my only problem light in the house.
Let me try to convince you otherwise.
In the case of the light I mentioned in my earlier post, I could hear the arcing in the ceiling rose. On dismantling the fitting, I could see the scorching on the plastic components. I could also smell the acrid odour of melting plastic.
Once I had replaced the wiring, the bulbs lasted more than a week, and I was satisfied I had correctly diagnosed and cured the problem.
Convinced?
Thanks for the responses.
To answer some of the earlier questions:
I’m using normal 75 watt GE light bulbs.
There is no noticeable vibration in the kitchen area.
The bulb always burns when I flip the switch (never just by itself that I can recall).
It’s probably not the socket itself because this fixture has two sockets and they both have the same problem.
There is no flickering when it is working.
The wiring I believe is circa 1925. There are no circuit breakers, just some giant fuses. But as I said, other light fixtures operate normally.
I’ll study the suggestions and work on it this weekend, hopefully without hurting myself!
Do the bulbs always burn out together? If not, is there any correlation at all between the two (as far as when they burn out)?
Do they appear to be normal brightness for 75-watt bulbs?
Unfortunately I can’t answer the first question. I don’t believe I’ve ever two bulbs burning in the same fixture at the same time. It always seemed like a waste to me since one bulb gives adequate light. All I can say is that both sockets burn out bulbs at approximately the same rate.
They do appear to be normal brightness.
HEAT!
After dozens of prematurely burned out bulbs in my basement, I discovered that the lighting fixture’s design traps too much heat and that excess heat dramatically reduces the lifespan of the bulb.
Changed one of the fixtures. Presto!
I believe you, but does anyone have an explanation of why this would happen? If the bulb was visibly flickering, I can imagine that may cause the bulb to fail. If not, how can a short circuit (arcing) damage the bulb?
Exactly.
IIRC NEC lumps light sockets and cord sockets together as outlets; that’s why I used the term. This may have been a source of confusion.
In any case, sorry if I wasn’t completely clear.
Baraqiyal
Have you fixed your problem? Let us know what you found.
For starters: You can get a cheap voltage meter & check the voltage at the socket & let us know what it is.
I too, have a really old house & the electric comp had to come out really fast once & reground it…as I was getting 124 volts in the kitchen.
Perhaps the obvious is being overlooked here…perhaps you’ve got yourself a Poltergeist 
Cartooniverse
Before doing anything too drastic, I decided to go with a lower wattage bulb. Many of the posters wrote that heat could be the problem, which reminded me that when I moved in, there was a 50 or 60 watt bulb in the fixture. I don’t think I started having problems until I started using 75 and 100 watt bulbs. This also makes sense because the fixture is completely enclosed, and therefore would probably get too hot. Anyway, I’m keeping my fingers crossed.
60 watts is usually the largest bulb rating for a ceiling fixture.
I’ve seen a ceiling light that used a spot light. The light burnt out every week. Switching to a different bulb that allowed more air circulation past the bulb into the fixture cured the problem.