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Why Do I Need One?

Power surges are basically an increase in the current flowing to your wall. These surges can occur for a number of reasons.

The most familiar reason is lightning. If lighting strikes near a power line above or below the ground, this causes an increase in the electrical pressure headed for your house. This creates an enormous surge that can destroy electronic devices, start a fire in the house or even electrocute someone using an appliance.

Though these types of surges are probably what someone thinks of first when one mentions surges, they are not only very uncommon, but they would also overwhelm almost any surge protector along with the appliances that are connected to it. Never rely on a surge protector in a thunderstorm. Unplug your devices for absolute safety.

Much more common, and perhaps a bit underestimated, are more subtle, daily surges. When refrigerators, heaters, air conditioners, and other power-hungry appliances kick on there is a sudden, brief demand for more power. Anyone who’s ever seen the lights flickers when one of the appliances kicks on knows what I’m talking about. These small power disruptions can, immediately or over time, wreak havoc on the sensitive components found in equipment such as computers and home theater equipment. This scenario is perfect for surge protectors.

How Do They Work?

The most common surge protections used in the surge protectors are called metal oxide varistor or MOV. A MOV is made of a special metal called a semiconductor. Semiconductors only conduct electricity under certain special conditions. If these conditions are not present, no electricity can pass through the semiconductor. In a MOV, the special condition is a certain high level of voltage. Basically, if the voltage, or flow of electricity, is at a normal level, the MOV does nothing. When a surge of power travels through the line, the MOV is then able to conduct electricity and so it siphons off the excessive power, transferring it away from the device, safely into the ground. The MOV only siphons off the amount of power that’s ABOVE the normal level, so the TV or PC continue to run during this surge. The device connected to the surge protector actually has no idea that there was a surge in the line. It continues to operate as if nothing happened.

Now, the inherent problem with MOVs is that, with all the small surges happening all the time, they can wear out. Most surge protectors contain more than one MOV, but if the MOVs burn out, that means all surges will have nowhere to go but straight to the devices connected to the protector. This is why it is important to choose a protector with some type of indicator letting you know when MOV protection has failed, so you know to stop using the protector. These indicators can be an LED light or an audible buzzer.

Additional Protection:

Some surge protectors also offer fuses as a backup. These fuses can only handle a certain level of voltage. When the voltage rises above that level, the fuse actually melts, immediately stopping all current from flowing to the connected devices. These are great as a backup, if your MOVs burn out and you don’t know it. If the MOVs aren’t there to stop the surge, than the fuse will melt and take care of the job.

With modern home theaters and complex computer systems becoming more and more common, surge protection is no longer just about power cords. Telephone lines as well as cable TV lines can carry large surges as well, potentially damaging expensive equipment. Many surge protectors can be found that include connections for phone, internet, or cable lines. These typically contain fuses, much like the backup fuses discussed above. Again, if the voltage spikes too high, the fuse melts and saves the devices attached to the protector.

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