Cause : Ground fault comes when the power unit has detected a ground fault. This can happen when a live conductor comes into contact with a grounded object, such as a metal enclosure or the earth.

F30021 fault in siemens 6RA80 DC Drive indicate Ground fault. This means an electrical current flows to ground instead of following its intended path through a circuit.

1. Check the power cable connections.
2. Check the motor.
3. Check the CT.
4. Check the cables and contacts of the brake connection (a wire is possibly broken).
5. Check the braking resistor.