I recommend an isolated power supply for your computer.
Al Fasoldt's reviews and commentaries, continuously available online since 1983

T e c h n o f i l e
Summer storms can zap your PC if you're not careful

May 20, 2007

By Al Fasoldt
Copyright © 2007, Al Fasoldt
Copyright © 2007, The Post-Standard

   Most PC users know that lightning can fry a computer during a summer storm. But there's another danger that can cause just as much difficulty. It's the sudden loss of power while your computer is running.
   Files can be wiped out in a fraction of a second. Hard drives can even be damaged beyond repair.
   Fortunately, you can take three simple steps to protect your computer. I'll tell you how to do that this week.
   Every so-called "desktop" computer needs to be plugged in to a 120-volt electrical outlet in order to work. The power company supplies the necessary electricity to your home or office and to thousands of others around the clock. In most communities, this is very reliable.
   But in areas where electricity is delivered by overhead wires, lightning strikes and violent gusts of wind can topple trees and bring down transmission wires. If your community is like ours, you're probably used to the pattern -- a couple of loud thunderbolts, a sudden crack of lightning and a quick plunge into darkness.
   The stress this sudden loss of power puts on your PC can range from minimal (if your computer wasn't doing anything at the time) to catastrophic (if your computer was saving a file or making a copy of something). If the power flickers, going off and back on and then off again, the damage is likely to be multiplied.
   What can you do to protect your desktop computer? Obviously, your desktop PC can't get zapped by a power failure if it's not plugged in. So the ultimate protection is to unplug your computer before your area gets hit by a storm and to keep it unplugged until the weather clears up.
   There are two problems with this approach, as you can surely agree. Lightning sometimes arrives unannounced, ahead of the wind and rain, giving you no chance of unplugging your computer ahead of time. And if you're away from your home or office, there's no way you can pull the plug anyway.
   So this "ultimate" protection turns out to be unworkable for most of us. That's why I recommend the next best thing -- an isolated power supply for your computer. Such a device is called an uninterruptible power supply, or UPS.
   The idea behind a UPS is simple. You plug it into the wall socket and plug your computer into the UPS. It has a built-in battery that sends the proper electricity to your computer (or other appliance) without regard for the electricity coming in from the power company. If the power company's electricity goes dead, the UPS sails on, supplying power to your computer.
   Well, that's kinda-sorta the way it works. The battery will go dead fairly quickly in most inexpensive ($50-$80) UPS models. So, rather than letting your computer run out of power after a half-hour on the UPS, most manufacturers provide a program that senses when the power goes out. If the power doesn't come back on after a sufficient period, the UPS program gently shuts down your computer to make sure your files are safe.
   You can buy a UPS at most stores that sell computers. You shouldn't need a high-capacity model if you attach only your computer to it. Don't bother plugging the monitor or printer into the UPS; they don't need protection.