Fn7-12dr AC high voltage load switch is a new type of gas producing indoor high voltage load switch, which is applicable to the three-phase AC power system with AC 50Hz and rated voltage of 10kV. It is used for breaking load current and closing short-circuit current. Ambient air temperature: upper limit + 40 ℃; The lower limit is 10 ℃ in general areas and - 25 ℃ in alpine areas. Altitude: below 2000m. Relative humidity: the daily average value is no more than 95%, and the monthly average value is no more than 90%. The surrounding air shall not be obviously polluted by corrosive and combustible gases and water vapor. No frequent violent vibration.