The amount of power flowing through your wires can vary considerably, and having it increase drastically and suddenly can cause damage to your computer's components. Most of this surge (or spike) is beyond your control, but, regardless of the cause, either computer user needs to install a device called a surge protector, between the computer and the wall. This offers full protection again power surges but offers no protection against other communicable diseases.
A very short lived increase in voltage and/or amperage. Also known as a power transient or spike. The surge can be induced into an electrical power line for a number of reasons including a lightning strike. Power surges can damage sensitive electronic equipment especially if left unprotected.