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Letter to the editor

Easy does it when screwing in a lightbulb

By Tim Carter, Special to the Times
Published November 3, 2007

A: Your bulbs failed because someone screwed them in too tightly into the socket. Seriously!

If you look at the base of a traditional lightbulb, you will see a droplet of solder. This solder connects to one end of the filament inside the bulb. The other end of the filament connects to the aluminum threads at the base of the bulb.

Inside the socket of the light fixture, you will see a brass tab. When the light fixture is new, this tab is bent upward at about a 20-degree angle. You may have noticed in the past that as you screw in a new lightbulb and the light is turned on, the lightbulb comes on before the bulb is tight in the socket. This happens because the brass tab makes contact with the droplet of solder.

But some people twist lightbulbs into sockets far too tightly. After doing this several times, the brass tab flattens at the bottom of the socket. The droplet of solder is not always consistent from the factory, and if there is the slightest air gap between the solder and the brass tab, electrical arcing occurs between the base of the bulb and the brass tab when the light switch is turned on.

As long as this tiny arc is present, the bulb will work. But the arcing can and does erode the solder. Once the gap between the solder and the brass tab gets too big, the electrical arc can't make the jump. As soon as this happens, the bulb acts as if it has burned out, when in fact it is still good.

Try this: Remove the bulb and turn off the light and power to the circuit. Using needle-nose pliers, slowly pull the brass tab up at a 20-degree angle. The bulb will work again as soon as you turn the power and switch back on and reinsert the bulb into the socket.

You're right, there are lots of choices in the lightbulb aisles these days. One of the most interesting products is the halogen bulb. This bulb produces a vibrant white light that makes colors look crisper, and the bulb stays at nearly full brightness for its entire life.

If you want energy-saving lightbulbs, pay close attention to the fluorescent lightbulbs at the retail store. You can buy compact fluorescent bulbs that use 75 percent less energy than a traditional lightbulb. For example, if you now use a 100-watt regular lightbulb, buy a fluorescent lightbulb that is rated right around 25 watts. Believe it or not, it will produce the same amount of light as the old-style lightbulb.

You can also buy full-spectrum bulbs that filter out the yellow light produced when the filament burns. This happens as the light passes through the glass of the lightbulb. The rare-earth element neodymium is fused into the glass and acts as a highly effective yellow-light blocker. Because no yellow light escapes from the lightbulb, colors of all the things in your home are crisper and vibrant. Reds will be redder, and skin tones will be more alive.

My wife and I use all three of these new lightbulbs in our home, and love how they make things look different, especially our lower electric bill!

Tim Carter is a licensed contractor. To view previous columns or tap into his archive of information and sources of building materials, visit Ask the Builder at www.askthebuilder.com. You can write to Tim Carter at P.O. Box 36352, Cincinnati, OH 45236-0352.

[Last modified November 1, 2007, 16:40:24]