NOT LONG AGO a reader called with a reasonable question. "I'm going on vacation," he said, "and I'm wondering if I should unplug my computer and other equipment while I'm gone."
The answer: It can't hurt. In fact, unplugging your gear while you're away can save a lot of grief in a season when thunderstorms pose a danger to virtually everything electronic.
But the call reminded me that it's a good time to talk about making sure your computers, printers and other gadgets are protected against electrical surges and spikes - even when they're plugged in.
Surges and spikes are brief but spectacular increases in voltage that can fry delicate equipment. A surge lasts longer than a spike, but they're both very short - measured in nanoseconds, or billionths of a second.
The biggest surge in nature is lightning, but contrary to popular belief, direct lightning strikes cause relatively few problems for homeowners because they're so rare. In fact, if lightning does strike your house or the power lines nearby, there's almost nothing you can do to keep your plugged-in equipment from frying, short of installing a whole-house surge suppressor - an expensive proposition.
Much more common are household surges, caused by heavy equipment such as air conditioners, freezers and refrigerators that cycle on and off, momentarily creating a jump in voltage. Often the damage is cumulative - you might not notice it till your computer or some other gadget quits before its time.
During the summer, lightning strikes can cause power interruptions, which create two potential headaches. The main problem is that power often returns with a surge in voltage that can damage unprotected components.
The second problem is that your computer could grind to a halt while it's writing data to the hard drive, which can scramble your data or even make the computer unbootable. Shutting down suddenly without properly closing important system files can cause trouble the next time a PC boots up, too - even if there's no real damage.
To deal with the first hazard, you'll need a good surge suppressor. For the second you'll have to go a step further - an uninterruptible power supply to keep your system chugging along.
