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Lightning can zap, hot weather can sap power

Published Oct. 9, 2005

The onset of hot weather means it's time to take a little extra care with your computer, because summer is not kind to electrical gadgets.

The main problem is that your computer's lifeblood _ its supply of electrical power _ is subject to all sorts of glitches, natural and man-made.

There are two potential problems with electricity _ too much and not enough.

Too much comes from lightning. The thunderstorm is one way that Mother Nature tells us she's still boss, and these storms, with their spectacular lightning displays, are more common in the summer months.

A lightning bolt sends thousands of volts of static electricity crashing through anything in its path. For critical computer components, designed to operate on a relatively small trickle of electricity, a major power surge can mean disaster.

Most commercial buildings are well-grounded against lightning strikes, but homes may not be. You've heard tales from friends who have had lightning strike a television antenna and blow out all the sets in the house. The same thing can happen to a computer.

Unfortunately, even the best surge suppressors are untrustworthy bodyguards in this worst-case scenario. At home, I generally unplug my computer equipment when a thunderstorm is passing overhead.

This doesn't mean you have to stop what you're doing when you hear the first rumble. You can tell how close the lightning is by counting the seconds that elapse between a lightning flash and the resulting thunderclap.

Sound travels at 1,100 feet per second, so a five-second delay means the storm is well over a mile away. When the gap dips below five seconds, I generally shut down and wait till the storm passes. It rarely takes more than half an hour, and the center of a swiftly moving storm may take only a few minutes.

Modems need extra attention because they're connected to two sources of electricity _ the wall outlet and the telephone line. The circuitry connected to the phone line is even more sensitive to voltage fluctuations than other computer hardware. In rare cases, a lightning strike on a telephone line will produce enough voltage to fry the modem without your realizing it until the next time you turn it on.

Because the voltages involved are relatively low, special surge suppressors for modems are effective here. Some surge-suppressing power strips designed specifically for computers have phone jacks built in to protect modems. These are worth the small extra cost.

While lightning strikes are relatively rare, blackouts and brownouts are not. Blackouts can be the result of nature _ a lightning hit on a substation or high winds that take down power lines. They also can be man-made. Summertime is the peak season for construction, and if there's any going on in your neighborhood, you can count on some guy with a backhoe cutting an underground power line.

When the temperature rises into the 90s, demand for electricity may be so high that your utility company reduces the voltage to a point at which it's dangerous for computers. This is known as a brownout. In extreme situations, utilities may resort to something they euphemistically call "load shedding," which means turning off the power to various parts of town for 15 minutes at a time.

There are two dangers here. If the power goes off while your machine is writing data to its disc drive, you risk losing the file you're working on, or worse, trashing the hard disc completely.

When the power returns, there may be a voltage surge big enough to knock out your system. On top of this, power often is not restored cleanly. The electricity may flicker on and off for an hour.

Luckily, there are relatively inexpensive solutions to these problems. At the very least, you should have a reliable surge suppressor. These are most frequently sold in the form of power strips that plug into a wall outlet and provide four or six protected outlets for your computer equipment.

An even better bet is an uninterruptible power supply, or UPS. The UPS is a battery backup unit that plugs into the wall outlet. You plug your computer equipment into the UPS. When everything is fine, the UPS filters the flow of electricity, protects against surges and trickle-charges its battery.

When it senses a severe drop in voltage, the UPS instantaneously switches over to battery power and usually sounds an alarm to let you know there's a problem.

Once prohibitively expensive for homes and even small businesses, these devices now cost as little as $100. More money buys more power and longer battery life. An inexpensive unit may provide only 10 minutes of power for a single computer. More expensive power supplies can handle a variety of computers, monitors, printers, scanners, modems and the like for an hour or more.

One hint: Don't plug a laser printer into a UPS unless you have battery power to spare. With their built-in heating elements, laser printers soak up electricity, and whatever you're printing when the lights go out can undoubtedly be printed again later.

If you have a network in your office, the file server that handles your critical business data should have its own UPS, preferably one that can keep it running for a while.

None of these is a substitute for the most important precaution of all _ backing up your hard disc regularly. A computer may be worth a few thousand dollars, but the data it stores can be worth your livelihood.

If it's impractical to back up your data to floppy discs, invest in a tape backup unit now. Tape backups are easy to use and will even do their work while you're asleep. Available for as little as $250, they're worth their weight in gold.

Michael J. Himowitz is the computer writer for the Baltimore Sun. Distributed by the Los Angeles Times-Washington Post News Service.