IE:00018 on a SolaX Power SolaX X1-Mini G4: ResidualOCP - Overcurrent (residual current) Protection Fault
Short answer
On a SolaX Power inverter, IE:00018 means: ResidualOCP - Overcurrent (residual current) Protection Fault. The inverter stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: ResidualOCP - Overcurrent (residual current) Protection Fault.
Part involved: Residual current / ground fault monitoring (RCMU).
Likely causes:
- Leakage current / connections.
Is it safe?
Switch the inverter off at its isolator if the code comes back.
| Does the inverter stop? | Yes |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The inverter stops until the fault clears or is reset.
Resetting itself: may retry; persistent or repeated trips need investigation.
Manual reset: sometimes.
What you can check
- Read and note the exact code and time from the inverter display or app (screenshot).
- Check the solar/battery AC isolator and the consumer-unit breaker/RCD are ON (do not reset a breaker that trips again immediately).
- Do not touch DC cabling or open the inverter; manufacturer says only a qualified technician should handle this.
- Where the SolaX manual says 'press the ESC key to restart the inverter', a homeowner can do that on the display. Steps that say 'disconnect PV+/PV-/battery' are for the installer only.
What the engineer will check
- Isolate AC and DC, wait for capacitors to discharge (5 min SolarEdge).
- Reconnect strings one at a time to find the faulty string.
- Insulation-resistance test.
- Check AC neutral/earth connections.
Who to ask for: PV installer.
Certification: Electrician competent in grid-connected PV (BS 7671 Section 712; IET Code of Practice for Grid-connected Solar PV), ideally the original MCS-certified PV installer; brand-approved/trained installer to keep manufacturer warranty.
What you might notice
Sources
- X1-MINI G4 User Manual Version 9.0 (Version 09, 30 Jun 2026) ↗ · 9.0 · page PDF p.97 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026