Tom Wells, president of Integrated Media Systems in Vienna, Va., still remembers vividly his first-hand encounter with the destructive force of lightning. The real-life scene played out like a Wes Craven movie.
“I was in a friend’s vacation home down on the water, near Virginia Beach,” Wells recalls. “We were in the upstairs loft, looking out over the water. We watched the whole thing as lightning hit the cabin. An electrical plate blew off the wall, flew across the room, and buried itself a half-inch into a pine-paneled wall. It made a believer out of me.”
A lightning strike, of course, is the most dramatic example of a power disturbance that can destroy electronic home systems. But less severe power surges and spikes also can take their toll on system performance and longevity.
A five-year study by the National Power Laboratory of Best Power, based in Necedah, Wis., concluded that 60 percent of power surges and spikes are created inside the house because of refrigerators, air conditioners, washing machines and other motor-driven appliances.
The other 40 percent originate from the outside world: lightning strikes, power grid problems or accidents involving downed lines or damaged power poles.
Many dealers recommend that clients safeguard all sensitive electronic equipment with surge protection. A “primary” or “whole-house” surge suppression system installed at the service entrance is merely the first line of defense - not a substitute for plug-in units and strips connected directly to electronic equipment inside the home.
Surge protectors not only prevent catastrophic equipment failure, but also improve system reliability by protecting integrated circuits, says Andrew Benton, an electrical engineer with New Frontier Electronics, a manufacturer of surge protection products.
Lightning Strikes; Electronic Equipment Blows
A lightning strike is made up of opposite charges of electrical energy. A negative charge builds in the bottom of the cloud closest to earth, and a positive charge occurs directly beneath the ground.
These charges are separated by a non-conducting belt of dry air between the cloud and earth. When the two opposite charges build up further, and the dry air belt becomes moist, lightning strikes.
“There is absolutely no way to protect a piece of equipment in a building that gets a direct hit by lightning,” Benton says. “Usually, however, when a building or utility pole gets hit, the equipment itself does not receive the direct discharge. The equipment receives a surge through the building wiring.”
A lightning strike doesn’t even need to be all that close to cause damage, either. The intense electric and magnetic fields associated with a 20,000-amp strike can induce about 2,000 volts at a speed of 300 feet in just three seconds.
“We spend a lot of time educating our customers about what can happen when lightning strikes,” says Keith Kennedy, vice president and general manager of Florida Home Entertainment Design in Bonita Springs, Fla.
Choose Surge Protectors Based on Application
Michael Cogbill stresses that there’s a wide variety of surge suppression products available, with a broad price range.
“I wouldn’t sell a client anything that would be less than $75 to $100 for a six-outlet plug-in suppresser,” he says. “And I can tell you why that’s so much better than the one you can buy at a discount store for $12. The $12 one has a real simple circuit in there that’s going to clip at maybe 470V on the plus or minus side.”
The more expensive surge protector strips “track the sine wave that our electrical current comes in,” Cogbill explains. “So if the voltage swings between 120 and -120, so does our protection.”
Florida Home Entertainment Design likes mixing and matching surge suppressers to suit each application.
“We analyze everything in the system and make sure every connection is protected,” says Keith Kennedy. “Let’s say you’re installing a home theater with DSS. The surge protector for that can provide coverage electrically for the telephone line, the cable line and the DSS. And you’ve made a $180 add-on sale.”