FN7-12DR 12KV load break switch 400A 630A 1.General The AC H.V load switch FN7-12DR is a new type gas using indoor hv load break switch, adapt to 3 phases AC electrical power system with the frequency 50HZ and rated voltage 12KV. It is used to break out the load current and cut the short current. Rated voltage: 12 KV 1min power frequency withstand voltage, Earth to earth and between phase: 42 KV 1min power frequency withstand voltage, Isolation fracture: 48 KV Lightning surge withstand voltage, Earth to earth and between phase: 75 KV Lightning surge withstand voltage, Isolation fracture: 85 KV Rated current: 400A / 630A 4S Thermo stable current(virtual value): 12.5KA / 20KA Rated current(KV. Peak value): 31.5KA / 50KA