Within FZN25-12D / T630-20 type indoor AC switch is a three-phase AC 50Hz, rated voltage of 12kV indoor devices for industrial and mining enterprises distribution substations reach other occasions, as the protection and control of electrical facilities for the division load current, loop current, no-load transformer and cable charging current. FZRN25-12D / T □ exchange within -31.5 type indoor high voltage vacuum load switch - fuse combinations are three-phase AC 50Hz, rated voltage of 12kV indoor devices for industrial and mining enterprises distribution substations reach other occasions, for load control and short circuit protection purposes. Equipped with the grounding switch that can withstand short-circuit current. Actuator can be manual and electric, to facilitate remote control three power system requirements. FZN25-12D, FZRN25-12D load switch and combination of electric three-phase power supply ring network city distribution and industrial power equipment for load control and short circuit protection. Due to the combination of electrical transformers and other electrical equipment protective effect against more reliable than open circuit, more economical, especially for the ring, double radiation power supply unit and box-type substation. Manually open and close operation of the conventional load switch on the right, but also provide a positive action or left operation according to user needs.