1、Basic Values: This surge protection device has Uc of 420V, Imax of 60KA, In of 30KA, and an operating ambient temperature of -40°C to +80°C. 2、Working Principle: Under normal conditions the protection device is in a high resistance state, when the grid due to thunder or other reasons for dealing with surge overvoltage, the surge protector will be immediately in the nanosecond time quickly conductive, the surge overvoltage into the earth, thus protecting the power equipment on the grid. 3、Return Normal: When the surge voltage through the protection device, and after the overvoltage disappears the protection device revert to a high resistance state, so as not to affect the normal operation of the grid. 4、Limit Transient: Surge protection device is mainly used to limit the transient overvoltage amplitude, absorption, consumption or discharge of inrush current energy. Make in the overvoltage category of higher situations, can make the protected electrical components from an overvoltage category to another lower overvoltage. 5、Usage Scenario: In the 3 phase and 4 wire system, the 3 phase wires and a neutral wire to ground are connected between the protection device and being suitable for home, farm, office building and so on.