1404 on a SMA Solar Technology AG Sunny Island 4.4M / 6.0H / 8.0H: Disconnects from the utility grid due to phase conductor failure/overload at terminal AC2
Short answer
On a SMA Solar Technology AG inverter, 1404 means: Disconnects from the utility grid due to phase conductor failure/overload at terminal AC2. The inverter keeps running with some functions stopped. An engineer is needed to fix the cause.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: Disconnects from the utility grid due to phase conductor failure/overload at terminal AC2.
Part involved: Sunny Island battery inverter.
When it shows: Disconnects from the utility grid due to phase conductor failure/overload at terminal AC2.
Likely causes:
- Reduce total power of loads (stagger use); ensure no short circuit at AC2.
Is it safe?
| Does the inverter stop? | Partly |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The inverter keeps running with some functions stopped.
Resetting itself: yes.
Manual reset: Autostart after malfunction (limited number of attempts, then 10-minute wait) per SMA 14.1; some errors must be acknowledged via the user interface.
What you can check
- Read the event in the Sunny Island web interface / Sunny Portal and note it for your installer.
- Switch off or stagger large appliances running on the backup/off-grid supply (e.g. kettle, oven, pumps), then see if the system recovers.
What the engineer will check
- Check load profile vs Sunny Island rating, battery bank voltage/charge, temperature sensor wiring, fans; parameter changes via installer login.
Who to ask for: Battery / off-grid installer (SMA Sunny Island trained).
Certification: Qualified electrician competent in battery energy storage (IET Code of Practice for Electrical Energy Storage Systems); manufacturer-trained installer.
What you might notice
Sources
- Operating manual SUNNY ISLAND 4.4M/6.0H/8.0H ↗ · SI44M-80H-13-BE-en-15 Version 1.5 · page 143 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026