Protect PC as summer heat hits

While the "ILOVEYOU" virus is getting all the bad press these days, most computer users face a potentially more serious danger from a source that no one can control: the weather.

The summer onslaught began early in our neighborhood this year, with a brief but rip-roaring storm this month that brought 2-inch hail, lightning, thunder, flooding and power outages for thousands of homes and businesses.


Things will get worse as the season progresses, which means it's a good time to think about protecting your PC against the blackouts, brownouts and other electrical gremlins that come with hot weather.

The least expensive option is a power strip equipped with a good surge suppressor. While nothing except unplugging your system will protect against a direct lightning strike, a surge suppressor will handle normal fluctuations in current and the serious spikes that occur when power returns after a blackout.


While you can buy basic surge suppressors for $7 or $8 -- and they're certainly better than nothing -- cheaper models are more likely to fail or wear out. Better surge suppressors also come with filters that keep out line noise from other gadgets in your home or office. You'll find perfectly good strips selling for $20 to $50.

Look for a surge suppressor designed specifically for computers, as opposed to one designed for televisions and other appliances. Make sure it has lights that show whether it's turned on and whether its protection is effective. This can be important because a suppressor "dies" a little each time it blocks a surge. When the circuitry wears out, the unit won't protect your equipment properly. If you live in an area with frequent power outages, it's a good idea to replace your surge suppressor every couple of years, and certainly after a major hit. You'll know when that happens because the suppressor might be blackened or melted.

The most important measure of a surge suppressor's protection is its "joule" rating, which indicates how much energy it can absorb. Look for a total joule rating of at least 700 for maximum safety. Also look for a "clamping voltage" (the point at which the surge protection kicks in) of 400 volts or less and a response time of 10 nanoseconds or less.

If you use your computer to communicate, be sure your suppressor has a modem protector. Modems are particularly sensitive to fluctuations in phone-line current, and they can be ruined by surges too small to affect other components. By plugging your modem into a surge suppressor's phone jack and running another cord from the suppressor to the wall jack, you'll avoid this danger.

While protecting your computer against electrical damage is important, a surge suppressor won't deal with the threat that's most likely to cause grief -- the loss of power itself. When the lights go out, at the very least you'll lose whatever you were working on. Worse yet, if your computer is writing to its hard drive, you could wind up with a scrambled disk.

Even if your computer isn't doing anything important when the power goes out, neither Microsoft Windows nor the Macintosh operating system enjoys having the plug pulled. During a normal shutdown, they write important data to the hard drive and close critical system files. When you restart a PC after an unexpected interruption, you may find it won't work properly -- or it may not start up at all. In fact, Microsoft says the biggest single cause of problems reported to its tech support center is an improper shutdown.

For that reason, the best protection against electrical problems is an uninterruptible power supply, known in the trade as a UPS (not to be confused with the UPS truck that delivers the gadget). This is essentially a rechargeable battery that sits between your electrical supply and your computer. You plug the UPS into a wall outlet and plug your equipment into outlets on the UPS.

When the power goes out, the battery kicks in and your PC keeps running for a few minutes until you can shut it down properly. A good UPS will also protect against surges, filter out line noise, and boost the voltage to the proper level during brownouts.


More expensive units have a cable that connects the UPS to the serial port on your PC, where special software running in the background monitors the battery. After a power failure, when the battery juice is almost gone, the program will save your work and shut down the PC. But don't pin your hopes on this setup. I've tried a few of these programs, and they've often caused more problems than they've solved.

Most UPS systems have four to six outlets, half of which are backed up by the battery and half of which are merely protected from surges and spikes. To keep your PC running as long as possible, plug as few devices as possible into the battery-protected outlets. I apply battery backup to my computer, monitor and cable modem but leave everything else on regular, surge-protected outlets. Never plug a laser printer into a battery backup because its heating element draws too much current and the printers themselves are sources of line noise.

When shopping, remember that more money gets you more operating time when the lights go out. This capacity is measured in volt-amps, but calculating how many volt-amps your PC needs can be tricky.

Your best bet is to consult one of the manufacturers' Web sites, most of which have online power calculators. For about $100, you'll find units that will keep a standard home PC and monitor running for five minutes or so. But the price goes up steeply after that. If you want 10 minutes to half an hour, expect to pay between $200 and $500.

Here are some sites to check:

American Power Conversion:


MGE UPS Systems:

Tripp Lite:

SL Waber: