The use of switchgear under normal operating conditions is specified in the EN 62271-1 as follows:
• The maximum ambient temperature is 40 °C, the average value over a period of 24 h is max. 35 °C. The minimum ambient temperature is –5 °C. For our indoor switches the class "Minus 5 indoors” is speci- fied.
• Solar radiation has no significant impact.
• The altitude at the place of installation is max. 1000 m above sea level.
• The ambient air is to have no significant contamina- tion through dust, smoke, corrosive and/or flamma- ble gasses, fumes or salts.
• The following conditions apply with regard to humidity:- average value of relative air moisture measured over 24 h is max. 95 %,
- average value of water vapour pressure over 24 h is max. 2.2 kPa;
- average value of the relative air moisture over a period of one month is max. 90%
- average value of the water vapour pressure over one month is max. 1.8 kPa;