Controller shows F22 Ground Fault; generator may trip off-line.

Safety first: Ground faults can present shock and fire hazards. De-energize the generator and affected circuits before testing. Use a qualified electrician for insulation testing.

• Isolate circuits: Open branch breakers one by one to identify which circuit causes F22 when re-energized. Keep the problematic circuit off until repaired.
• Inspect wiring and equipment: On the suspect circuit, check for damaged cable insulation, water in outlets or junction boxes, and signs of arcing. Repair or replace damaged components.
• Check neutral-ground bond: Verify that neutral-ground bonding is configured according to Siemens and local code requirements. Incorrect bonding can cause nuisance ground fault trips.
• Insulation resistance test: Use a megohmmeter to test insulation resistance between conductors and ground on the suspect circuit. Low resistance indicates a fault that must be corrected.
• Retest: After repairs, clear F22 and test operation. If F22 persists with all loads disconnected, the fault may be within the generator or ATS and requires professional service.