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Troubleshooting 5 min read Apr 22, 2026
Why Is My Inverter Showing a Ground Fault Error?
A GFDI or ground fault error on your inverter doesn't always mean a major problem — but it does need immediate attention. Here's what it means and what to do.
What Is a Ground Fault?
A ground fault occurs when electrical current flows along an unintended path to ground — usually through damaged cable insulation, a failed panel, or a connection issue. Modern inverters detect this using a Ground Fault Detection and Interruption (GFDI) circuit and shut down automatically to prevent fire or shock hazard.
Common Causes
- Damaged DC cables — UV degradation, rodent chewing, or physical abrasion
- Water ingress — into junction boxes or connectors after heavy rain
- Failed bypass diodes — inside panel cells
- Faulty MC4 connectors — corroded or improperly mated pairs
What To Do
- Don't reset and ignore it. A persistent GFDI trip indicates a real fault that will worsen.
- Note the error code — Different inverter brands (SMA, SolarEdge, Enphase, Growatt) use different codes. Record it before calling a technician.
- Isolate the array — If you're comfortable doing so, switch off the DC isolator at the inverter.
- Call a certified technician — Ground fault location requires insulation resistance testing (megger) and string-level diagnostics.
How We Find the Fault
Our technicians use calibrated megger instruments to measure insulation resistance string by string, isolating the faulty section in most cases within 1–2 hours.
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