Crest Factor Problem With Lighting

Definitions

• Crest factor describes the difference between the higher current required to turn on a light, called the starting current, and the normal operating current of a light, called the operating current. The term "crest factor" applies to ballasts, electrical devices used most commonly in fluorescent light fixtures to control the amount of current that travels from an electrical circuit to the light bulbs.

Limits

• The manufacturer will specify on the inside of the fixture or in the instruction manual that came with the fixture the maximum wattage bulbs allowed. If you place higher than recommended watt bulbs into a light fixture, the crest factor will have an unbalanced ratio, resulting in reduced life span of your lighting, according to the Lighting Research Center.

Considerations

• While improper light bulbs most frequently cause a crest problem, you may have a bad ballast. Ballasts provide resistance to electrical current so that the bulbs receive the proper amount of electricity, but this resistance weakens over time. You can remove the ballast, which typically takes the form of a round cylinder in a fluorescent light fixture, and replace it with a new one.

Warning

• If you replace the bulbs and the ballast and still have a problem with crest factor, you may have a problem with the wiring connected to your fixture or the electrical supply, according to Philips Lighting Electronics. This problem can occur due to corroded wiring, a malfunctioning electrical breaker in your panel box, improper wiring or wire that has grounded out due to a small cut in wire insulation. You will have to trace the wire connected to the light fixture back to the panel box.