Comments on: Why do the lightbulbs in my office burn out all the time?

Question: Why do the lightbulbs in my office burn out all the time?

pornucopia — Wed, 22 Feb 2006 09:04:51 -0800

Why would the lightbulbs burn out much more frequently in one room of my house?

In the last 6 months I've replaced the lightbulbs in my study at least twice each. Same with the bulbs in the laundry room. I haven't had to replace the bulbs anywhere else in my house in that time. Any ideas?

By: mhuckaba

mhuckaba — Wed, 22 Feb 2006 09:06:52 -0800

Turning on lightbulbs causes a large current to run through them initially, which decreases their life span greatly. If you turn them on and off frequently, this could be the cause.

Also check and make sure you're using the correct bulbs for the lamp you're putting them in.

By: Pollomacho

Pollomacho — Wed, 22 Feb 2006 09:07:40 -0800

Could be bad wiring. Could be temperature. Could be vibrations. Could be coincidence.

By: paulsc

paulsc — Wed, 22 Feb 2006 09:20:16 -0800

In North America, normal houses are fed with 240 volt AC wiring in the form of two hot legs of 120 volt each, a neutral, and a ground. Each hot leg, relative to neutral, delivers 120 volts to the normal 15 or 20 amp branch circuits, and 240 volt appliances like the stove, dryer, and air conditioner are run off both hot legs, together. But some big appliances use 120 volt, and if several of these, like a refrigerator, a dishwasher, a large screen plasma TV, a couple of computers, etc. wind up being connected to the same 120 volt leg, on different 15 amp branch circuits, one side of your house feed is going to be heavily loaded, while the other side is not. The heavily loaded side will sag voltage below 120 volts, while the unloaded side, coupled through the outside transformer winding feeding your house, has no choice but to go high, to try to maintain the 240 volt nominal. The result is that you can have branch circuits which will be up around 130 to 140 volt, much of the time. And that will blow bulbs.

Solution? Rebalance your loads by connecting approximately the same load across both feeds of the house, until all branch circuits have within 2 or 3 volts of the same voltage reading. That can involve moving some wires and circuit breakers in the main box, if you don't have flexibility to move the actual appliances.

By: desuetude

desuetude — Wed, 22 Feb 2006 09:33:50 -0800

Dust and dirt on the surface of the bulb can make them burn out fast. The laundry lint and paper dust might be contributing to the decline of those bulbs.

By: meehawl

meehawl — Wed, 22 Feb 2006 09:39:14 -0800

Previously on Ask.

Vibrations are the most likely culprit. You can order special vibration-hardened bulbs. The washing machines are your main culprit.

By: stilgar

stilgar — Wed, 22 Feb 2006 09:50:31 -0800

try a compact fluorescent lightbulb...probly wont burn out on your for 3-7 years. save you a tonn on your energy bills as well.

By: roboto

roboto — Wed, 22 Feb 2006 14:22:12 -0800

mhuckaba & paulsc are correct. In many applications in fact, a warming voltage is applied before ramping a bulb up to full voltage explicitly to extend bulb life. A bulb that is cycled on an off repeatedly will have a MUCH shorter lifespan. There are also many situations created in a home which degrade the electric signal with noise, cause imbalances, and/or leaks. [more reading]

By: JamesMessick

JamesMessick — Wed, 22 Feb 2006 14:37:42 -0800

desuetude, dust and dirt? Please.

Is it possible that these bulbs are just on that much more? I know what you mean, it seems like the lightbulbs at the bottom of my stairs burn out much, much more frequently than they should.

By: Goofyy

Goofyy — Thu, 23 Feb 2006 02:13:32 -0800

JamesMessick:
Dust and dirt on a bulb increase the internal heat, which shortens its life.

Interesting read, I have just such a problem in my kitchen light. The light in my office is the same bulb, but lasts far longer. The kitchen is, of course, full of appliances that draw good loads (electric griddle, micro-combo, coffeepot, etc).