Isolation fault
The inverter has detected insufficient insulation resistance between the PV array and earth and has disconnected.
Common causes
- Moisture ingress in a DC connector or junction box
- Damaged DC cable insulation or a pinched cable
- Water in the array after heavy rain
- Actual ground fault in the DC installation
Safe checks
- 1Do not touch DC wiring or open any enclosure.
- 2Note the code and the time it appeared, since weather patterns help an installer.
- 3Disconnect the DC isolator only if the manufacturer instructions for your model say a non-technical user may do so.
- 4Contact a qualified installer — isolation faults are a DC-side diagnostic task.
Related error codes
1027 (DC-INTF)Moderate
Solis
DC interference detected
September 2026View
1033 (PV ISO PRO)High
Solis
PV array isolation fault
September 2026View
1034 (I-Leak-Pro)High
Solis
Leakage current protection triggered
September 2026View
1040 (AFCI Protection)Critical
Solis
Arc-fault protection triggered
September 2026View
Brands commonly affected
When to call a technician
Call a qualified technician if the device repeats the fault after a manufacturer-approved restart, shows a burning smell, has damaged or discoloured wiring, or if the symptom involves the battery, inverter power stage or any sealed high-voltage component.