901 on a SMA Solar Technology AG Sunny Boy: The grounding conductor is not correctly connected
Short answer
On a SMA Solar Technology AG inverter, 901 means: The grounding conductor is not correctly connected. 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: The grounding conductor is not correctly connected.
Part involved: AC wiring / country data set.
When it shows: The grounding conductor is not correctly connected.
Likely causes:
- SMA corrective measures: Ensure that the grounding conductor is correctly connected.
Is it safe?
| Does the inverter stop? | Yes |
|---|---|
| Severity | Fault — needs a manual reset once the cause is fixed |
| Engineer needed? | Yes |
The inverter stops until the fault clears or is reset.
Resetting itself: no.
Manual reset: See engineer checks.
What you can check
- Read the event number and message in the SMA Energy app / Sunny Portal (ennexOS) or the inverter's web interface and note the date/time for your installer. A red LED on the inverter means an event has occurred.
- This points to an installation/configuration issue - contact your installer; do not attempt wiring checks.
What the engineer will check
- Check PE/earth, L/N polarity and neutral connection at the inverter and feed-in meter; check country data set (Grid Guard code needed to change); restart self-test where applicable.
Who to ask for: Electrician / PV installer.
Certification: Qualified electrician (BS 7671; MCS-certified PV installer for work on the PV array/DC side).
What you might notice
Sources
- Operating manual SUNNY BOY 3.0/3.6/4.0/5.0/6.0 ↗ · SBxx-1AV-41-BE-en-21 Version 2.1 · page 90 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026