What is the maximum altitude for operation of Harmony XB4/XB5 Operators.

Harmony XB4 and XB5 range operators are qualified to work in its nominal characteristics for a maximum altitude about 2000 meters.

The rarefied atmosphere at high altitude reduces the dielectric strength of the air and hence the rated operational voltage of the relay.
It also reduces the cooling effect of the air and hence the rated operational current of operator(unless the temperature drops at the same time).

Derating factors to apply depending the altitude are as follows :