- Error code
- E025
- Category
- Insulation resistance
- Manufacturer
- ABB / FIMER
1What the error means
Low insulation resistance. It is logged in the history without stopping operation, but it indicates an insulation fault on the DC side that will get worse.
On the display or in the monitoring software it appears as Riso Low.
2Possible causes
- Moisture in junction boxes, connectors or modules
- Damaged or worn DC cables
- Faulty module
3What to do
- Note whether it appears after rain or early in the morning.
- Measure the insulation resistance of each string to earth.
- Check connectors and junction boxes for moisture.
- If the PV generator is fine, check the inverter's measuring circuit.
4Repair by Aineas
You send the inverter to our lab in Thessaloniki. We diagnose it, inform you of the fault and the cost, and the repair starts only after you approve it. Every inverter is tested under simulated operating conditions before delivery.