Error 303 on a Growatt inverter: PE abnormal - voltage of Neutral and PE above 30 V
Short answer
On a Growatt inverter, Error 303 means: PE abnormal - voltage of Neutral and PE above 30 V. The inverter stops until the fault clears or is reset. An engineer is needed to fix the cause. The wording differs by model range — each is shown below.
Reviewed 24 September 2026 · 2 sources
What it means
On the MIN 2500-6000TL-X
The manual says: PE abnormal - voltage of Neutral and PE above 30 V.
Part involved: Residual current / ground fault monitoring (RCMU).
Likely causes:
- Neutral/earth wiring fault.
On the SPH 3000-6000TL BL-UP (48 V battery hybrid)
The manual says: NE abnormal - earth fault alarm (red LED).
Part involved: Residual current / ground fault monitoring (RCMU).
Likely causes:
- earth fault alarm (red LED).
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.
- Growatt's manual says 'restart inverter'. A homeowner can switch the inverter off and on at its AC isolator/breaker; leave DC switching to the installer unless the manual step says to switch DC off immediately (Error 202).
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
- Growatt MIN 2500-6000TL-X Installation & Operation (User) Manual, general EN 2022-06 ↗ · EN 202206 · page PDF p.22 · Reviewed 24 September 2026
- Growatt SPH 3000-6000TL BL-UP User Manual EN 202512 ↗ · EN 202512 · page PDF p.62-66 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026