Defensive Computing

Everyone knows to use a surge protector for their computer. But which one? How do you choose? Welcome to surge protector school.

As their name implies, surge protectors prevent voltage spikes from entering a computer (or whatever else is plugged into them). They are available in a variety of types and, to paraphrase the manual that came with a Dell server, usually provide a level of protection commensurate with the cost of the device. In other words, you get what you pay for.

A surge protector is not a power strip, although a low end model may look like a power strip. Power strips are just extension cords and won't protect a computer from power surges. If it doesn't say "Surge Suppressor," it is probably just a power strip. You can also judge by the price, power strips are cheaper than surge suppressors. A device with no Joules rating is a power strip.

There are many features that go into making a good surge protector.

To begin with, electrical surges can happen on any wire. Thus, you need a surge protector that protects every wire going into your computer. This includes the phone line, if you use dial-up or DSL, and Ethernet network cables, if the computer is on a LAN. Lower end surge protectors only protect the electrical outlet; to get Ethernet or phone line protection, expect to pay a bit more. As a starting point, expect to pay from $20 to $35 for a surge protector.

Have you ever blown a fuse? Some surge protectors work like fuses, and when they absorb all the electricity they can, they die. They may die either from a single big surge or from absorbing many small surges over a long period of time.

What then?

Most likely, a dead surge protector will indicate the fact that it is no longer protecting your equipment with some type of indicator light. However, months after installing it, will you know what the light means? You may not even see it, if the surge protector is behind furniture.

When the surge suppression no longer functions, some surge protectors will continue to provide electricity to the devices. Better models cut off the juice, which protects your devices and makes sure you know to replace the surge protector. Never use a surge protector that provides unprotected power! The last time I checked, the current models of both APC and Tripp Lite would never provide unprotected power to your devices.

You may be thinking that fuses have been replaced by circuit breakers. When there is an overload, a circuit breaker trips and you can easily switch it back later without having to go to the hardware store and buy a new fuse.

Better surge protectors work this way, too. These models are designed to cut off power in a surge rather than absorb it. As a result, they should not wear out over time. There will be a little button that pops out, and you can pop it back in after the surge.

How can you tell if a particular surge protector works like a fuse or circuit breaker? One hint is the warranty, if it has a lifetime warranty then it probably works like a circuit breaker. I suggest only purchasing a surge protector with a lifetime warranty. In general, both APC and Tripp Lite surge protectors have lifetime warranties.

Next up, clamping speed and let-through voltage.