This momentary rise in voltage can start inside or outside a home, and can fry sensitive electronic equipment like computers. Suddenly the energy these devices were consuming is diverted elsewhere in the form of excess voltage. Surges also happen when the electric company switches power from one geographic area of the grid to another as supply and demand in the region changes. The best, least expensive way to deal with most sources of power interference is to plug sensitive, expensive electronic equipment into a surge suppressor. Established manufacturers include Panamax, Tripp Lite and American Power Conversion.
Suppressors work by absorbing some of the electrical surge and diverting the rest to ground.
This Underwriters Laboratories rating is the standard for surge suppressors. It ensures the suppressor can reduce a 6,000V surge, for example, to a harmless 330 to 400V one. An internal fuse. When suppressors are overwhelmed by a surge of power that lasts more than the few milliseconds they're designed to handle, an internal fuse breaks the circuit, preventing the surge from reaching connected devices. A solid warranty.