Res Cur Fault on a Fox ESS H1 G2 single-phase hybrid inverter: The residual current is high
Short answer
On a Fox ESS inverter, Res Cur Fault means: The residual current is high. The inverter stops until the fault clears or is reset.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: The residual current is high.
Part involved: residual current monitoring (RCMU).
When it shows: Residual current above limit.
Likely causes:
- Leakage current to earth from damaged cable insulation or wet components.
Is it safe?
Switch the inverter off at its isolator and call an engineer.
| Does the inverter stop? | Yes |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
The inverter stops until the fault clears or is reset.
Resetting itself: yes.
Manual reset: Wait for a while to check if back to normal; else seek help.
What you can check
- Read the full code and message on the inverter screen or in the FoxCloud app and note the date/time for your installer.
- Check the inverter's AC isolator next to the inverter and the solar/battery breaker in the consumer unit are ON (do not reset a breaker that trips again - call your installer).
What the engineer will check
- Insulation test PV and AC wiring; check for water ingress; check RCD coordination.
Who to ask for: MCS-certified solar PV installer (DC/string work) or the original installer.
Certification: Work on DC strings and inverter enclosures: competent PV installer (MCS-certified installer for warranty/SEG continuity); electrical work notifiable under Part P (England & Wales) or equivalent.
What you might notice
What owners and engineers report
1 owner and engineer report mentions this.
- Solar or battery breaker/RCD keeps tripping on the H1 G2 single-phase hybrid inverter: 1 report
Sources
- H1(G2)/AC1(G2) Series User Manual ↗ · V1.0.8 · page 47 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026