You know that electricity is dangerous, so you probably avoid sticking your fingers into live light-bulb sockets and electrical outlets. Your computers may not have fingers, but they're sensitive to electricity, too, and it's up to you to protect them from a variety of electrical dangers.
Protecting against electrical surges
An electrical surge is a sudden spate of very high voltage that travels from the electric lines to your house and ultimately to your computer. Computers are particularly sensitive to surges, and a real surge can fry your computer. The chips burn up, and your computer becomes a doorstop.
Most of the time, surges occur as a result of a lightning strike, but the danger of a surge also exists if there's a brief blackout followed by a return of electricity. During the return of power, the voltage can spike. (See the section "Protecting against lightning hits.")
You can safeguard against spikes by plugging your computer into a surge protector. The surge protectors that are commonly used look like electrical power strips, usually with four or five outlets. Read the specifications before you buy a surge protector to make sure that it's rated for real surge protection. (Voltage can rise by 10 volts or hundreds of volts, so make sure that the surge protector you buy can handle these extreme surges.)
Surge protectors work by committing suicide to protect your computer. They absorb the surge so it doesn't travel to your equipment. (Some surge protectors have reset buttons that bring the strip back to life.)
If a power surge hits any piece of equipment that is attached to your computer by cable, the surge can travel to your computer. Therefore, plugging the computer into the surge protector isn't quite enough; you also have to use the surge protector to power the accessories that are connected to your computer.
 | Because any surge received by a single computer can travel over the network cable to the other computers on your network, make sure that all the following equipment for each of your computers is plugged into surge protectors: |
- External removable drives
| Notice that printers are not on the list. Never plug a printer into the same surge protector that your computer is already plugged into. (In fact, if you have a laser printer, you should never plug it into the same circuit as your computer.) You need to protect your computer from your printer, especially if you use a laser printer or a powerful color ink jet printer. These printers use a lot of power, and if they're on the same circuit as your computer, you're probably causing minor brownouts for the computer, which can harm your hard drive and your data. |
Protecting against telephone line surges
Large networks can be destroyed during a lightning storm, because the surge comes through the telephone lines, not the electrical lines. This is what happens: Lightning hits the telephone line; the surge comes through the telephone jack in the wall; it travels along the telephone cable from the wall to the modem; it travels from the modem to the computer's motherboard; it travels from the motherboard to the rest of the computer parts, including the network interface card (NIC); the NIC sends the surge out to the network cable; the cable sends the surge back to every NIC on the network; and each NIC sends the surge to its computer's motherboard. Every computer on the network is fried.
| In most communities, the power company installs lightning arresters, which help diffuse the effects of a direct lightning hit on the electric lines. However, telephone companies often don't protect its phone lines against lightning. When a lightning storm is close, unplug your modem telephone cable at the wall jack and then unplug the computers. |
 | If your telephone company has fiber optic lines, you don't have to worry as much about lightning hits because those lines don't conduct electricity. Ask your telephone company what types of lines are connected to your home. |
Protecting against lightning hits
If lightning hits your power lines or your house, your surge protector may not be able to protect your equipment against the resulting surge. Thousands or tens of thousands of volts — sometimes more — result from a lightning strike. A surge protector can provide only so much protection, and a direct lightning hit exceeds that limit.
The only protection against lightning strikes is to unplug your computers and all your computer equipment. Stop working. Then walk around the house and unplug other equipment with chips that could fry during a lightning storm (like your microwave oven, VCR, and so on).
Protecting against power loss
When you're running Windows, you can't just turn off your computer when you don't want to use it anymore. You must initiate a shutdown procedure using the Shut Down command on the Start menu. Otherwise, you may have a problem restarting your computer, or you may run into mysterious problems when you try to use software and Windows features after a power failure.
The electric company doesn't know and doesn't care about the need for an orderly shutdown, and if the folks there did know or care, they couldn't do much to warn you about a power failure, giving you time to use the Shut Down command.
You can keep your computers running long enough to complete an orderly shutdown of all your software and the operating system if you have an uninterruptible power supply (UPS). A UPS is a mega-battery that you plug into the wall, and you then use the UPS outlets to connect your computer and monitor. If your power fails, your computer draws power from the battery, giving you enough time to shut down everything.
UPS units come in a variety of power configurations (measured in watts). Some have line conditioning, in addition to the battery feature. Some have software that performs the orderly shutdown for you. (The UPS unit connects to your computer through a serial port to communicate.) This is a nice feature if your power dies while you're away from the computer. The cost ranges from about $75 to several hundred dollars, depending on the wattage and the features you want.
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