How Does
How Do Surge Protectors Work?
By Isaiah
eHow Contributing Writer
The Purpose of a Surge Protector
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Every country has a standard voltage, which is a rating of the power of electricity when it flows into a building. In most of America, electric current is rated at 120 volts. Every once in a while, however, a thunderstorm, equipment failure or other problem can create a brief surge in the power supply. A surge can quickly destroy computers and other electronics. Surge protectors are designed to protect electronic equipment and prevent surges from occurring.
Shunting the Current
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Current flows into a wall socket and through an appliance by the hot wire. It flows back out through the cold wire. A third wire, called the ground, allows static or excess spikes of electricity to be sent into the ground to dissipate. Many surge protectors are attached to the ground through a device called a metal oxide varistor (MOV.) Normally, the MOV resists the flow of electricity, stopping electric current from flowing into the ground. When the voltage spikes, however, the MOV becomes less resistant and the surge can be sent safely into the ground wire. Some surge protectors use a special gas tube with electrodes at each end instead of an MOV. The gas in the tube does not let electricity pass from the electrode attached to the power supply to the one attached to the ground. When the voltage jumps, however, it ionizes the gas, and the tube becomes conductive, letting electricity flow into the ground.
Killing the Power
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The ground wire can only conduct so much current at once. If the current surges extremely high, or if the surge lasts too long, the ground wire will not be enough protection. Most circuit breakers use a fuse as a backup. A fuse is a tube with a thin wire filament carrying current through it. The more power running through the fuse, the hotter it gets. If the power gets too high, or stays high for a while, it will burn the fuse up, stopping the flow of current to protect electronics plugged in to the device. If this happens, the surge protector will have to be repaired or replaced.
eHow Article: How Do Surge Protectors Work?
