Solar Ground Fault & Arc Fault — What They Mean and What to Do
A ground fault or arc fault code on your inverter means the system has shut down for a real safety reason. Here is what caused it and why you should not reset it without a professional inspection.
Do not reset a ground fault or arc fault without inspection
Both fault types indicate current flowing somewhere it should not. Resetting without finding the cause can create a fire hazard or shock risk. The fault protection exists specifically to prevent those outcomes. Call a licensed solar contractor.
Ground fault (GFDI) — what it means
A ground fault detection interrupter (GFDI) trip means the inverter detected current flowing from a live conductor to the grounded metal parts of the system — the racking, conduit, or panel frames. This should never happen in a healthy system.
Common causes in Fresno and Clovis: squirrel-chewed wiring where bare copper touches the racking; damaged wire insulation from heat or abrasion; water intrusion into a junction box; a panel with internal insulation failure.
What happens to production: The inverter shuts down completely. Zero production until the fault is located, repaired, and the system is reset by a licensed contractor.
Arc fault (AFCI) — what it means
An arc fault circuit interrupter (AFCI) trip means the inverter detected the electrical signature of arcing — electricity jumping across a gap. Arcing generates intense heat (up to 35,000°F) and is a leading cause of solar-related fires.
Common causes: loose or corroded MC4 connectors (the plug-in connectors between panels); damaged wiring; connections that have worked loose over years of thermal expansion and contraction. Fresno's extreme summer heat — regularly 105–115°F — accelerates connector degradation.
What happens to production: Same as a ground fault — complete shutdown until the arc source is located and repaired.
How we diagnose and repair electrical faults
Inverter error code review
We read the fault code and event log from the inverter to narrow down the fault location and type.
Visual inspection
We inspect all accessible wiring, connectors, junction boxes, and conduit runs for visible damage.
Electrical testing
We use insulation resistance testing and continuity testing to locate the fault precisely.
Repair and verify
We repair the fault, reset the system, and verify production is restored before leaving.
Frequently asked questions
What causes a ground fault in a solar system?
Ground faults occur when current flows from a live conductor to ground through an unintended path. Common causes: damaged wire insulation (from critters, heat, or abrasion against racking), water intrusion into a junction box or conduit, a failed panel with internal insulation breakdown, or a loose connection that has corroded. In Fresno, squirrel-chewed wiring is the most common cause we see.
What causes an arc fault in a solar system?
Arc faults occur when electricity jumps across a gap — typically at a loose, corroded, or damaged connection. The arc generates intense heat and is a leading cause of solar-related fires. Common causes: loose MC4 connectors, corroded terminals, damaged wiring, or connections that have worked loose over years of thermal expansion and contraction. Fresno's extreme summer heat accelerates connector degradation.
Can I reset a ground fault or arc fault myself?
No. Both fault types indicate a real electrical problem — not a nuisance trip. Resetting without finding and fixing the cause can create a fire or shock hazard. The fault protection exists specifically to prevent those outcomes. A licensed solar contractor needs to locate the fault, repair the cause, and verify the repair before the system is returned to service.
How long does it take to diagnose and repair a ground fault?
Diagnosis typically takes 1–3 hours depending on system size and fault location. Simple faults (a single chewed wire or loose connector) can be repaired same day. Complex faults involving multiple damaged sections or water intrusion may require a follow-up visit for parts. We provide a written quote before any repair work begins.
Will my solar system restart automatically after a fault is cleared?
Most modern inverters restart automatically once the fault condition is cleared and the system is reset. String inverters typically require a manual reset after fault repair. Enphase microinverter systems often resume production automatically once the faulted unit is replaced or the fault is cleared. We verify production is restored before leaving the site.
Is a ground fault or arc fault covered by my solar warranty?
It depends on the cause. If the fault resulted from a manufacturing defect in a panel or inverter, it may be covered under the equipment warranty. If it resulted from physical damage (critters, weather, improper installation), it is typically not covered. We document the fault cause with photos, which can support a warranty or insurance claim.
Related guides
Ground fault or arc fault on your system?
Call us — do not reset the fault without inspection. We serve Fresno, Clovis, Madera, and all of the Central Valley. License #1063682.