3902 on a SMA Solar Technology AG Sunny Boy: The feed-in conditions for the utility grid are not yet fulfilled

What it means

The manual says: The feed-in conditions for the utility grid are not yet fulfilled.

Part involved: DC input / irradiance.

When it shows: The feed-in conditions for the utility grid are not yet fulfilled.

Likely causes:

• SMA corrective measures: Ensure that the PV module is not covered by snow or otherwise shaded. Wait for higher irradiation. If this message is displayed frequently in the morning, increase the voltage limit for starting grid feed-in. Change the parameter Critical voltage to start feed-in . If this message is displayed frequently with medium irradiation, ensure that the PV module is correctly rated.

Is it safe?

The inverter keeps running with some functions stopped.

Resetting itself: yes.

Manual reset: Automatic when condition clears.

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.
• From the ground, check whether panels are covered by snow, leaves or heavy shading; wait for brighter conditions (do not go on the roof).
• This message is normal at dawn, dusk and in very dull weather.

What the engineer will check

• If shown in good light, check array sizing/string voltage against inverter start voltage, module defects, and 'Critical voltage to start feed-in' parameter.

Who to ask for: PV installer.

Certification: Qualified electrician (BS 7671; MCS-certified PV installer for work on the PV array/DC side).

What you might notice

• Solar panels not generating at all
• Solar generation lower than usual

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 94 · Reviewed 24 September 2026

A code explains what the controller detected, not a confirmed root cause.

Reviewed: 24 September 2026