So you buy a surge/spike protector powerboard and you're fine, right? After all, there are quite a few brands of powerboard that now come with an impressive "Connected Equipment Warranty", offering thousands or even tens of thousands of dollars of insurance if something plugged in through the powerboard gets toasted. How can you lose?
Well, you can lose technically, and you can lose legally.
The technical side is simple enough. No ordinary cheap powerboard ("cheap" definitely includes "a hundred US bucks") actually provides very good protection from line current gremlins. It may protect you once from a big-ish spike, or several times from smaller ones, but it won't last forever.
Cheap surge filters are all based around components called Metal-Oxide Varistors (MOVs). MOVs pass current only when the voltage across them is above a set value, and they react to overcurrent in microseconds. A circuit breaker or fuse can take tens of milliseconds to trip or blow; that's much too slow for spike suppression.
Unfortunately, MOVs will only work a few times, at best. The more work they have to do, the closer to death they come. A surge/spike powerboard with a toasted MOV is now... just a powerboard.
Better surge/spike boards are meant to tell you when their MOV's died via a little light or even a buzzer, but they commonly, actually, don't. A surge/spike filter that's been in use for some years and still reports its MOV as perfectly healthy is, probably, lying.
Better surge suppressors use two other kinds of spike-sinking component. Gas arrestor tubes (also known as gas discharge tubes, or GDTs) are much tougher than MOVs, but respond too slowly to be useful for many applications, including computer protection. But you'll still find them in the better power filters, because they can handle the load of a really big surge, after some other component has (possibly) bravely given its life to intercept the first several microseconds of overvoltage.
. thats what i was really getting at - if its right above head then of course, things get unplugged.
