Insulation Fault / Low Insulation Resistance

What does 1083 mean?

This status code is displayed on the user interface of the Fronius Primo GEN24 inverter if the measured insulation value drops below the configured "Threshold for the insulation warning". This indicates a potential insulation fault within the PV array or DC wiring. The insulation warning can be activated or deactivated, and the measurement mode (Exact/Fast) and threshold (100000 - 10000000 Ω) are configurable parameters.

• Low insulation resistance between the PV generator's DC conductors and ground (PE).
• Physical damage to PV module backsheets, DC cables, or connectors, leading to moisture ingress or direct contact with ground.
• Environmental factors such as high humidity or condensation causing temporary reduction in insulation resistance.
• Degradation of cable or module insulation due to aging, UV exposure, or mechanical stress.

Click steps to track your progress.

1. 1

   Verify the "Threshold for the insulation warning" parameter setting on the inverter's user interface; ensure it is set appropriately (e.g., 1 MΩ minimum).

2. 2

   Isolate the inverter from the AC and DC sides, then measure the insulation resistance of each PV string and individual PV modules to ground (PE) using a megohmmeter (e.g., at 500 VDC or 1000 VDC). Expect values >1 MΩ per string.

3. 3

   Visually inspect all DC cabling, connectors, and PV module frames/backsheets for any signs of damage, wear, moisture ingress, or potential ground faults.

4. 4

   If the insulation fault persists or is intermittent, systematically disconnect PV strings or individual modules and re-test insulation resistance to pinpoint the exact location of the fault.

5. 5

   Ensure all cable glands and junction box entries are properly sealed to prevent moisture ingress.