Solar · Error codes · Sunsynk
F43Sunsynk · ECCO single-phase hybrid SG05LP1
F43 on a Sunsynk ECCO single-phase hybrid SG05LP1: Grid voltage out of range (over-voltage)
Short answer
On a Sunsynk inverter, F43 means: Grid voltage out of range (over-voltage). The inverter stops until the fault clears or is reset.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: Grid voltage out of range (over-voltage).
Part involved: grid voltage.
When it shows: Grid voltage above limit.
Likely causes:
- Grid over-voltage; wiring; settings.
Is it safe?
| 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: Check voltage vs spec; seek help.
What you can check
- Read the full code and message on the inverter screen or in the Sunsynk Connect 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).
- Recurring sunny-afternoon trips suggest high local voltage - ask your installer to log it and contact the DNO.
What the engineer will check
- Check grid voltage, cable voltage rise, terminations.
Who to ask for: Installer, with DNO (network operator) if grid supply is at fault.
Certification: None for homeowner checks; any grid-protection setting change needs installer and DNO consent (G98/G99).
What you might notice
Sources
- Fault Codes Causes & Solutions Version 1.0 ↗ · Version 1.0 · page 9 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026