Operation condition:
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.
Technical requirements:
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.