Light Bulbs Burn Out Quickly

By Tim Carter
©1993-2008 Tim Carter

Summary: Light bulbs can flicker or burn out long before they are supposed to. The failure is not in the wiring and it can almost always be traced to an operator-error problem.

Related Articles:  dimmer switches, compact fluorescent light bulbs, three and four way switches

DEAR TIM: Four of the six bulbs in the recessed lighting in our kitchen ceiling keep burning out. I just replaced one and it burned out in an hour. I am using 65 watt bulbs. Our house is only 3-years old. Are the bulbs the wrong size? Is there a problem with the wiring? Cory Dixson, El Dorado Hills, CA

DEAR CORY: The problem with the premature failure of the light bulbs has nothing to do with the wattage or the wiring. My first guess is that it can be traced to the person who has installed the light bulbs or previous owners of your home. I think they are twisting them into the socket too tightly.

The flickering of light bulbs in lamps and fixtures can also be caused by bulbs that have been installed too tightly into light fixtures.

Look right in the center of the photo. You can clearly see the brass tab and if you look closely you can see it is raised up off the bottom of the socket. PHOTO CREDIT: Tim Carter
Look right in the center of the photo. You can clearly see the brass tab and if you look closely you can see it is raised up off the bottom of the socket. PHOTO CREDIT: Tim Carter
At the base of light fixture sockets you will find a brass tab. This tab is bent at an angle when the fixtures are new and will spring back and forth if depressed slightly. Do not ever stick your finger in the socket to test this, as you can get shocked if the power is on to the fixture.

Take several new light bulbs and inspect the base of each one. You will quickly notice that the bottom of most light bulbs has a small droplet of solder in the center of the base. More importantly the size of this drop of solder is not consistent from light bulb to light bulb. It is close in size, but not always the same size or height.

If the brass tab at the base of the socket does not make firm contact with the bottom of the light bulb, a small electrical arc can happen that starts to melt the solder. Over a period of time, the solder can deform and the gap between the solder and the brass tab gets larger.

When this happens, the electrical contact between the brass tab and the solder is broken and the light bulb acts as if it has been turned off when in fact the switch is on and the bulb is still in working condition.

This is the bottom of a standard light bulb. You can see the drop of silver-colored solder in the black ring. This solder droplet is not always the exact same size in every bulb. PHOTO CREDIT: Tim Carter
This is the bottom of a standard light bulb. You can see the drop of silver-colored solder in the black ring. This solder droplet is not always the exact same size in every bulb. PHOTO CREDIT: Tim Carter
To prevent this arcing you must be sure the brass tab is always at about a 20 degree angle inside the bottom of the socket. People who twist bulbs in tightly will depress and flatten the tab so it does not spring back when a bulb is replaced.

If you discover the tab is flattened, then you must turn off the power to the lights, and as an additional safety safety measure, turn off the circuit breaker to the lights. Use a needle-nose pliers and carefully grasp the sides of the brass tab and slowly pull it up so the end of the tab is about one quarter inch off the base of the socket.

When you install a bulb always do so with the power on and the light switch on. As soon as the bulb comes on, only continue to turn the bulb one-eighth of a turn. If you screw the bulb in too tightly, you will once again flatten the brass tab.





Comments:

Mike Samson
06 Dec 2007, 17:35
Hi,

I just bought those new energy saver lightbulbs from GE, the spiral type. My problem is that I can't get them to work in several of my lights. I know the energy saver bulbs are good as I tested them on other lights. However, when I try the bulbs in the lights I want to replace, I only get darkness. The bulbs were on sale and supposedly I should save a bundle. I won't save a dime if I can't get them to work and keep using the old style bulbs which work.

Thanks,
Mike
AsktheBuilder
06 Dec 2007, 17:39
Mike,
Did you test them in a socket you know works for sure? I think it is a power issue.......
Marion
28 Dec 2007, 20:42
Thanks for this information with the brass tab. I've had several problems with this and now I see what's happening. As soon as the bowl game is over I'll check the ceiling fan light in the bedroom.
Skeptical
08 Jan 2008, 18:01
Tim, your summary is both misleading and absurd. The chances of the brass tab being bent to the degree that contact cannot be made with the bulb is next to nil, especially since most if not all fixtures don't have a stop on the bulb thread, thereby ensuring contact. The most likely culprits are poor (dirty) electrical supply, excessive vibrations of the bulb while lit and poor bulb manufacturing quality.

For example, if a door nearby a fixture were to be close with sufficient force to vibrate the filament (while lit), that's likely enough to blow the bulb.

Moreover, it's very likely that today's bulb manufacturers are cutting corners to save costs and subsequently sell inferior bulbs. What's my proof? Not necessarily scientific, but how often has anyone found a 30 year old bulb still burning in fixture where multiple bulbs reside and have been replace many times over? Personally, it's happened lots of times. Ever wonder why?
AsktheBuilder
08 Jan 2008, 18:57
Dear Mystery Skeptical Person,
Believe it or not, the accuracy of this column was confirmed by a top research scientist that works for General Electric's Light Bulb Division in Cleveland, OH. I was there in person discussing this topic September, 2007 at their Nela Park campus.

You are correct that vibration can cause rapid failure. What you do not have access to is the scores of email I received from readers after this column appeared. Many had bulbs in places that had no vibration. Many were burning through bulbs in just days, new bulb after new bulb.

Once they pulled the tab back up in their fixtures, the bulbs stopped failing - in *every* case.

I would love to continue this debate with you. Please bring some hard data with you next time. Possibly between now and then we might have people comment who have had the same problem.
halcust
02 Feb 2008, 19:52
Re: Skepticals comments
Manufacturers may indeed be cutting corners but their intentions may not always be selfess. I recall a tv program years ago where the crew was filming in the Soviet Union, they were talking to a person in a warehouse and a crew member looked up at the lights and commented on how difficult it would be to change the bulbs. The warehouse person said "change bulbs? We don't change them."
He wasn't lying, they don't. Apparently they used filament so heavy they never burned out. The problem with that was they then also suck way more power. If this is true the manufacturers maybe cutting corners to save you money on your power bill.

A happy medium would be nice, or at least a choice with the power usage on the package so that you would know where you wish to spend the money.
Dave Marcus
06 Feb 2008, 13:31
Well, I found out trial and error about the socket base flap, and you are right. Do you think that voltage irregulariy or nonstandard voltage U.S., plays a role in blowing bulbs without even the switch being turned on? And what if the switch turn on blows the fresh bulb, could that ve voltage? And, if a fixture calls for 60w. could I use 100-watt, and still survice? These things keep me wondering, can you advise, as you are "into," and fianlly, would I know and how the switch is wired properly, some say it could be reverse wiring?
AsktheBuilder
06 Feb 2008, 16:48
Dave,
The line voltage in *most* locations is pretty consistent. Bulbs will burn out when a switch is turned on because of a thin filament. Call an electrician if you want a safety check.
Ron
21 Mar 2008, 17:15
I work taking care of 900 units and I find the little brass tab does get bent in so far the light doesn't work and bulbs do die young.But I find this only in cheap lighting,the better the light the less problens.
Carol
01 Apr 2008, 13:18
We are working on a house that is about 60 years old. Lights bulbs keep burning out. The couple that lived there before said that they could not keep bulbs burning. We just installed two new ceiling fans. One bulb burned out within an hour. I replaced all of the bulbs in that unit with ceiling fan bulbs (not that we are using the fans yet). By the next evening, all four bulbs had burned out. I have not had bulbs burn out in other locations. I read that it's not the wiring, but could it be the wiring since this is the oldest section of the house?

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