Light bulb keep on burning out

[Frank]

Tenant said they have to replace the light bulb in one of the rooms because it keeps on burning out. Its incandescent on a 120V circuit, any ideas? No such problem in other rooms.

[hallerb]

bad socket thats overheating and thats a safety fire risk issue.

or the fixture could be over lamped, with too may watts in it.

[John Grabowski]

Excessive vibration, loose contacts in socket, tenant plays basketball in house and keeps hitting the light fixture. Change the light fixture or try a rough service bulb.

[hallerb]

On Mar 12, 6:47=EF=BF=BDam, "John Grabowski" wrote= :

or a 130 volt bulb, or compact fluroscent.

my guess bad over heating socket

["Blattus Slaf]

They should turn it off once in a while.

[hallerb]

actually off and on a lot is worse than just leaving lamp on, its a thermal stress issue

[Phisherman]

Inspect the socket and check the voltage.

[diggmyspace]

[Joseph Meehan]

Vibration Moisture Poor contacts Heat in an enclosed fixture Wrong lamp for the fixture Halogen lamp installed without making sure there are no finger prints on it.

[Joseph Meehan]

Missed an important one

A floating neutral. This is a serious safety issue. It can cause a fire. It should have been listed first.

[PaPaPeng]

Its a lot easier and cheaper just to replace the socket. See if that helps.

[Jeff Wisnia]

I'd like to hear your explanation of how "a short" acts to burn out a light bulb.

Jeff

[AZ Nomad]

There's stray wire running from the 440 up at the telephone pole down to his light socket. Funny how nobody has noticed it before.

Seriously, the primary causes of short incadescent light bulb lifespan are 1) too much voltage (an AC voltmeter can check this) 2) too much heat 3) too much vibration (unfrosted bulbs can handle heat and vibration better as they run cooler) 4) poor quality light bulbs.

[Doug Miller]

A floating neutral causes enough other -- and more dramatic and widespread -- symptoms that, in the absence of those other symptoms, it does not merit consideration when the only observed symptom is short bulb life in a *single* socket.

[Dimitrios Paskoudniakis]

Another possibility:

The metal tab at the base of the socket could be pushed down from over-tightening a previous bulb, such that there exists an air gap between the tab and the base of the replacement bulb, causing current arcing, which then causes premature bulb failure.

Turn the circuit breaker off to the socket, use needlenose plyers to reach in and gently raise the metal tab to its original position.

Do not overtighten new light bulb.

[Don Klipstein]

Actually, in most incandescent lamps, cold starts don't do much actual damage with the jarring they do to the filament. What mainly happens is that an aging filament develops a thin hot spot, which experiences a temperature overshoot during a cold start.

Cold starts will kill aging filaments. However, avoiding cold starts does little to make filaments last longer - by the time they become unable to survive a cold start, the hot/thin spot is in a state that is reinforcing its thinness at a rate that is accelerating worse than exponentially - and the filament's hours are numbered no matter what.

Those thermistor-based soft-starting devices don't do much protection via soft-starting. I did an experiment and found that one of these, fully warmed up, dimmed the lightbulb enough to extend its life by about 50%.

Keep in mind the life expectancy of traffic signal incandescents in traffic signal use.

- Don Klipstein ( [e-mail])

[Joseph Meehan]

I disagree. If that floating neutral is pairing one light bulb say with a refrigerator it it may not cause an apparent symptoms on the other line but it can still be a danger and a cause.

[AZ Nomad]

bullshit. You can't push the contact so far in that it loses contact with an inserted light bulb. There's the bottom of the socket behind the contact. All an overtightened light bulb will do is squeeze the contact between the light bulb and the bottom of the socket.

Your suggestion is likely to product the arcing you are trying to eliminate by separating the contact from the bottom of the socket and producing a loose contact.

[hallerb]

=3DBF=3DBD 0/00 :)"

=3DEF=3DBF=3DBD7/8

g cold starts

long life, if thats what you want put the incandescent on a dimmer, dimmers even run at full voltage lose a few and lamp life skyrockets. the inside of the bulb will actually get black dimming the still burning lamp to the point you will want to replace it/

years ago i had a dimmer on a 300 watt light bulb for my elderly grandma.

300 watt so she could see good to read, low wattage for watching tv. about every 6 months i would replace the lamp its insides black.

that was OK a 300 watt without dimmer would last at most 2 months, high wattage equals short life.

today compact fluroscents are a far better choice

[scott21230]

Perhaps that particular light fixture is turned on and off a lot. If that's the case, the only light bulb that will alst is a LED type (which aren't widely available yet and don't come in high enough wattages to be useful yet).