1. Altitude: ≤ 1000m
2. Ambient temperature: +40 to -10°C
3.Relative humidity shall not be more than 95% at +20°C ambient temperature.
4. No gas, wapor or dust that may severely affect the insulation of contact box, no explosive or corrosive substance.
1.Coper contact to earth shall withstand power frequency test voltage (effective value) of 42kV for 5-minute and lightning impulse vpltage (peak value) of 75kV
2.Temperature of lead-out terminal shall not bemore than 65°C if the contact box is used for long time in rated current condition.