Surge Protective Devices,surge protector,arrester,SPD Surge Protective Devices,surge protector,arrester,SPD BY3 type SPD is suiting to A. C 50 ... protects the electric network shocked by the thunder or over voltage. This type belongs to Class 3 and the usage condition ... .0kV6.0kVInsulating resistance (Risol)> 100 MΩ> 100 MΩ> 100 MΩVoltage protective level Up<800 V< 1 kV< 1.5 kVResponse ...