Relay: higher voltage allowed at lower current?
Is it safe to use a 30VDC/1A relay for a voltage of 60V but a current of &lt;100uA?


No, the ratings for voltage and current are separate, not related to the power consumed by the load connected to the relay.

The current rating is to limit the self-heating of the relay due to its own resistance.

The voltage rating is to be sure the relay can disconnect properly, without an excessive arc forming between the contacts and damaging them.


  Didn't know that there has to be a min. current flowing through the relay. Why?


The issue is wetting current.

A certain current is needed to ensure that oxides and other surface contaminants are burned off the contacts when they touch each other.