Why light bulbs burn out

Light bulbs can't burn forever, and in reality, incandescent bulbs have a lifespan of around hours. Based on a usage of eight hours a day, a bulb should last roughly about four months. Compact fluorescent bulbs CFLs are supposed to last much longer, but this is not always the case. If you have replaced bulbs recently and the lifespan doesn't seem to be all that it should, the cause may be in the fixture itself or elsewhere in the circuit. Turning a light bulb on sends a jolt of electricity through the filaments, which is more likely to break it than a continued current — that's why light bulbs often burn out as you turn them on.

If you turn lights on and off frequently, you're likely reducing the lifespan of the bulb. If the supply voltage to your home is too great, bulbs will generally burn brighter and burn out much faster.

You can test for voltage at a standard volt electrical outlet, using a multimeter or a voltage tester ; be sure you know how to do this safely because the power will be on. If a test reveals a voltage higher than volts, have an electrician take a look at the problem, or contact your electric utility provider for recommendations. Another cause of bulbs burning out is excessive fixture vibration. A good example of this is a ceiling fan with a light fixture.

When a fan blade becomes unbalanced, the fan starts to shake, and the vibration jiggles the bulb filament and shortens its life. The same problem is common with light bulbs in garage door openers. You can try a rough-service bulb to correct this problem. These bulbs have heavy-duty filaments to withstand vibration better. The little metal tab at the bottom of a light bulb socket is the "hot" connection that delivers electrical current to the bulb the surrounding threaded metal is the neutral connection.

If the socket tab in the bottom of the socket gets pushed down too far, it can fail to make contact with the bulb. The problem here is not that the bulb has burned out, but that it no longer makes electrical contact with the socket. Then screw the bulb back in and see if it works. This repair may not be possible with old sockets, where the metal tab is brittle or has lost is spring entirely. In this case, the best solution is to replace the light bulb socket or the entire light fixture.

Although they have a reputation for lasting longer than incandescent bulbs, compact fluorescent CFL light bulbs are notorious for going bad before their time. CLFs are commonly touted to have a lifespan of about 10, hours, but if you've owned some of these, you know that this number is grossly exaggerated in many cases. The lifespan of CFL bulbs will also shorten if the light fixture is switched on and off too often.

A bulb rated for 10, hours might last only 3, hours if it is switched on and off many times a day for a few minutes each time.

The answer: Switch to LED light-emitting diode bulbs. They're more efficient, last longer, and they don't contain mercury like CFL bulbs do. When a bulb is loose in the socket, it can flicker on and off.

Simply tighten the bulb in its socket to correct the problem. Another issue may be a loose wire connection where the circuit wires connect to the fixture. Turn off the power and check the wires to make sure they are securely attached to the screw terminals. The fixture cord may be shorted, a plug could be defective, or the light socket may be shorted or defective. In any of these cases, replace the defective parts before resetting the breaker or replacing a fuse.

Prevent problems by using the appropriate bulb wattage. Energy-efficient bulbs such as LEDs have much lower wattages than standard incandescent bulbs while producing an equivalent amount of light.

Recessed light fixtures often have housings that extend into the attic. Some fixtures are designed to be covered with attic insulation, but some fixtures must have the insulation held back by at least 3 inches, to prevent overheating of the fixture.

Overheating causes bulbs to flicker or burn out early and are also a fire hazard. You can build a box around the fixture housing to allow for the appropriate space. Lighting is a necessity for every home or office, and more specifically, for every room. Decorating is one of the best parts about the holidays! August 13, By The Electric Team. High Voltage in the Home If the supply voltage to your home is higher than it should be, light bulbs will burn brighter, thus burning out much faster.

Excessive Fixture Vibration A good example of this is a shaky ceiling fan with a light fixture. Tripped Circuit Breaker or Blown Fuse A tripped breaker or blown a fuse can be a major culprit of bulbs not working.

At certain points along the filament, the tungsten evaporates, thinning the filament more and more. At other points, the coils of the filament get pushed close together. When the high level of current surges through a stretch of wire even thinner than the rest of the filament, the heat builds up even faster than the rest of the filament. When it heats a section of coils pressed close together, the heat between them can't dissipate as quickly as it does in the rest of the bulb.

The filament breaks or burns or simply melts. It turns out that the average light bulb is not designed to be turned on. It's meant to already be on. The initial stress on the tungsten filament is far higher than the light bulb can handle. Those who wish to prolong the lives of their bulbs for ecological or sentimental reasons can pre-warm them before turning them on to a cozy 2, degrees before switching them on. Top image by Andrew Price.