Insulation fault on PV generator (PV1)
Fronius · Primo GEN24
What does 301 mean?
The Fronius Primo GEN24 208-240 inverter has detected an insulation fault (ground fault) on the PV generator (PV1 string). This means there is an unintended electrical path between the PV array's DC conductors and ground, posing a safety risk and preventing power production.
Common Causes
- Insulation fault on PV generator (PV1).
- Water ingress into PV modules or junction boxes.
- Damaged PV cable insulation (e.g., rodent damage, mechanical stress).
Repair Steps & Checklist
Click steps to track your progress.
- 1
Safely disconnect the PV array (PV1) from the Fronius Primo GEN24 208-240 inverter using the DC disconnector and AC breaker.
- 2
Using a megohmmeter (insulation resistance tester), measure the insulation resistance of the PV1 string to ground (PV+ to ground, PV- to ground) - expect >1 MΩ.
- 3
Visually inspect all PV modules, cables, and connectors for the PV1 string for any signs of damage, moisture ingress, or degradation.
- 4
Check all junction boxes and combiner boxes for moisture, corrosion, or loose connections.
- 5
If the fault persists, isolate individual PV modules or sections of the PV1 string to pinpoint the exact location of the insulation fault.