New Bulb Keeps Burning Out

[Dimitrios Paskoudniakis]

I have a two-story family room, with two indoor flood lights in the ceiling, so it's a pain in the butt to replace them, bringing in my extension ladder.

I'm using the kind of bulb that the previous owner had, a 120V 65W indoor flood light bulb, which has a several inch diameter almost flat top. The bulb housing has a spherical cover with an opening for the bulb so that the bulb top completes the sphere. The housing can be rotated for directional lighting.

For one of the two lights, I've noticed that a replacement bulb keeps burning out within a couple of days of replacing. I just replaced the other one for the first time after we've been here 21 months, and it was there before that.

Any advice on how to resolve the one light fixture with a new bulb burning out within a couple of days would be appreciated.

[dpb]

Several possibilities and my suggested fix --

First, the fix (probably) -- buy 130V bulbs from a good-quality supplier, not the cheapest Chinese import you can find. The higher rated filament will last _much_ longer.

Now the questions/possibilities --

Are the replacements you're using the "low-priced spread"? See above...

Is there a vibration source near the one and not the other light? Like the kids' playroom above or something?

Is there a difference in venting or insulation or airflow obstruction near the second and not the first causing high(er) temperatures?

Check for loose connections of the fixture to the house wiring at the fixture and that the bulb base is clean and the socket base tab is making good contact w/ the bulb base.

Same switch controls both I presume? If not, check the switch connections on the second for similar issues as above.

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[Dimitrios Paskoudniakis]

I just surfed for an answer and found a site that indicates that a previously over-tightened bulb pushed a brass tab at the base of the housing down, so subsequent bulb installs don't make contact, causing an arc, which burns out the new bulb. It instructs to shut off the breaker, use needlenose pliers to pull the base tab up about 1/4 inch, turn on the power, install a new bulb, and only apply 1/8 turn after it comes on.

Sound right?

[Don Klipstein]

First, I would try a different brand of bulb, especially if you are not using a "Big 3" one (GE, Philips or Sylvania).

See if you can find the original bulb (that lasted 21-plus months) or remember what brand and model it was.

Second, see if the problematic fixture is being shaken by children jumping or bouncing basketballs or dropping heavy objects upstairs.

Third, if the fixtures are on different circuits, see if the problematic one has excessive voltage or is prone to unusual variations in brightness or is fed by a subpanel. Lightbulb blowouts are a common symptom of an neutral in a line feeding a panel, which can cause some circuits in your house to get overvoltage while others get undervoltage. This is not a common problem, but it is serious and if you actually have that it needs to be fixed urgently.

Fourth, see if water is somehow getting into the fixture and dripping onto the bulb.

- Don Klipstein ( [e-mail])

[Dimitrios Paskoudniakis]

Don't know, but if the cause is no contact with the housing causing an arc, this won't help.

The family room ceiling is an "A-shape, with a small level strip at the top. Each fixture is on each side of the "A", near the top. The bulb that burns out is under the master bedroom. The other fixture is on the rear side of the "A", which has it's own roof above. Because it is an "A" shape, there is a gap between the family room ceiling and the master bedroom floor.

See above.

I will. I haven't yet, but my other post references a web site that suggests this is the problem, not the bulb - socket base tab is pushed down from a previous bulb over-tightening.

Yes, one push button with dimmer controls both bulbs.

[Dimitrios Paskoudniakis]

I'm using Philips. I replaced the other good one last week also, and it is still fine, whereas the other one lasted a day or two. This tells me it is not the bulb.

Given the above, doesn't matter. Also, I pitched it, and it didn't have any obvious markings.

The fixture is under the master bedroom, and given it is on an A-shape ceiling before the highest point, there is a gap above.

Yikes. I didn't notice variation in brightness. Only when turning on a day or two later, nothing. I'll try a web site suggestion that a previous bulb was over-tightened so that there is no contact, causing an arc to the new bulb, and that the tab needs to be pulled up to ensure contact.

No water when I replace the bulb.

[dpb]

That's one of the possible causes I discussed.

I don't worry about precise dimensions or turns, simply make sure the base connection isn't mashed flat and has some spring left in it after you pull it up and is clean.

I simply tighten a bulb until it's firmly seated, but not excessively tight. It ain't rocket science.

I'll comment on the other response to Don here as well for _my_ :) convenience...that the new bulb failed doesn't really mean there wasn't one or more defective bulbs in the package(s). Infant mortality is a manufacturing issue and while the "Big 3" are still better at their QC and overall quality than the knock-off Chinese imports, I don't think they're up to what they used to be either simply because of those price pressures have forced them to economize, too.

The neutral problem w/ dimminng/brightening Don mentions is the point of the connection(s) checking -- if it's happening, it's unlikely you haven't noticed it if you use the room when the lights make a difference. If it does happen and only on the one fixture, that isolates it to the fixture itself as the location of the problem.

I still recommend 130V lamps in _any_ location that has difficult access simply because they will last longer owing to the heavier filaments.

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[RBM]

I'm assuming you are testing these "bad" bulbs in a known good socket after removing them from the recessed fixture. If it is a depressed tongue or other bad contact issue, the lamps will still be good. One problem I've found very often in recessed fixtures, especially Lightolier brand, is the wires are attached to the socket by rivets and sometimes from heat, the rivets loosen up and the connection randomly makes and breaks