Main Page | See live article | Alphabetical index A surge protector is an appliance designed to protect electrical devices from power surges. It works by monitoring the voltage supplied to an electric device. If the voltage level rises beyond a safe threshold, the dangerous excess voltage will be grounded (earthed) with the ground wire, protecting the device from being spiked (damaged by an electrical surge). The threshold varies depending on the region in which the surge protector is intended for use. The protection offered by the surge protector is rated by the Underwriters Laboratories. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.