1. The altitude of the installation site does not exceed 2000m;
2. The ambient air temperature is not higher than +40 °C and not lower than -5 °C; and the 24-hour average does not exceed +35 °C (except special order)
3. The relative humidity of the air at the installation site. The maximum temperature does not exceed 50 [%] at +40 °C, and higher relative humidity can be allowed at lower temperatures, for example, 90 [%] at 20 °C. Special measures should be taken for condensation that occasionally occurs from dry temperature changes.
4. There is no explosive medium in the air and there is no place to corrode metals and destroy the insulating gas and conductive dust.
5. There is no place where rain or snow invades.
6. The pollution level is level 3.
7. Installation category: The installation category of the main circuit of the circuit breaker is The auxiliary circuit and control circuit that are not connected to the main circuit are installed in category.