CKFZ-12D/630-20 type indoor medium-voltage vacuum load break switch (hereinafter referred to as the load switch) and CKFZR-12D/T125-31.5 vacuum load switch - fuse combination unit(hereinafter referred to as the "combination unit") are solely researched and developed by Zhuhai Comking Electric Co., Ltd. based on advanced technology at home and abroad under rated voltage of 12kV. It can be used for industrial and mining enterprises, high-rise buildings, residential areas, schools, hospitals, railway stations, docks etc. distribution system as indoor three phase network power supply equipment or terminal power supply equipment.