FZN21-40.5 type high-voltage vacuum load switch and combined electrical appliances, suitable for three-phase AC 40.5KV, 50Hz power system, or complete sets of power distribution equipment and ring network switchgear, combined power station and other supporting use, widely used in wind power generation , urban network construction and renovation projects, industrial and mining enterprises, high-rise buildings and public facilities, etc., can be used as ring network power supply units or terminal equipment, playing the role of power distribution, control and protection. The technical performance of this product meets the requirements of GB16926-1997 (AC high voltage load switch-fuse combination) and IEC420 (AC high voltage load switch-fuse combination).  This product has the advantages of large breaking capacity, safety and reliability, long electrical life, frequent operation, compact structure, small size, light weight, and basically no maintenance. It has the ability to break rated current, overload current, short-circuit current and prevent the equipment from running without phase. The switch has obvious isolation fracture, equipped with grounding switch and electric spring mechanism with closing ability, and has remote control ability.Ambient temperature:-10ºC-+40ºC Relative humidity:The average humidity of a day should be no more than 95%. The average humidity of a month should be no more than 90%. Earthquake intensity: not exceed 8 degrees. Saturated vapor pressure the average pressure of a day should be no more than 2.2kPa; the average pressure of a month should be no more Than1.8Kpa; The height above sea level:≤1000 m (Except special requirements) It should be installed in the places without fire, explosion, serious filth, and chemical erosion and violent vibration.