- 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
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