the ambient air temperature does not exceed 40 °C and its average value, measured over a period of 24 h does not exceed 35 °C. The ambient air temperature does not drop below –5 °C.
there is no influence from solar radiation.
the altitude does not exceed 1000 m for higher altitude use BIL correction factor.
the ambient air is not significantly polluted by dust, smoke, corrosive and/or flammable gases, vapours or salt and would be considered as having site pollution severity class (SPS)“very light” according to IEC 60815-1:2008.
the conditions of humidity are as follows:
the average value of the relative humidity, measured over a period of 24h, does not exceed 95%
the average value of the water vapour pressure, over a period of 24h, does not exceed 2,2k Pa
the average value of the relative humidity, over a period of one month, does not exceed 90%
the average value of the water vapour pressure, over a period of one month, does not exceed 1,8 kPa.
vibrations due to causes external to the switchgear and controlgear or earth tremors do not exceed the impact of vibrations caused by operation of the switchgear itself