Behaviour of Low-Voltage switchgear under conditions of very low air pressure or vacuum
What is the behaviour of Low-Voltage switchgear under conditions of very low air pressure (e.g. 1kPa) or vacuum?
According to IEC 60664-1 (Basis: Table A.2) an air pressure of 5,5kPA only allows the application of 1 /14,5 of the rated operational voltage to low-voltage switchgear. In addition to that heat dissipation is strongly inhibited under such a condition.
This means -in practical terms- low-voltage switchgear cannot be used in conditions of very low air pressure (e.g. 1kPa) or vacuum.