ZKESP-1170 can help protect your home from electric surges and prevent costly and destructive power surges. A power surge occurs when the line voltage goes higher than it is rated for and stays there longer than ten milliseconds. In today's high-tech world, computerized appliances and electronics can be damaged or destroyed by surges in electrical lines. Every day appliances are zapped by an average of 20 power surges. These surges are power fluctuations that go unnoticed except by your appliances. The end result can shorten appliance lifespan by as much as 30%. That’s like paying full price for an appliance, then getting to use 2/3 of what you paid for.