The short answer
Make sure PE is connected to the inverter.
Plain explanation
From the SMA manual for the Sunny Boy: Installer ensures PE connected. Installer only: DC and AC work on a live PV system is dangerous, so owners should note the code and call their installer.
Steps from the source
- Installer ensures PE connected
Source
SMA Sunny Boy 3.0-5.0 Operating Manual (SB30-50-1AV-40-BE-en-10), §12.2files.sma.de ↗
Where installers ask this
- Grid Failure - Solar company has gone dark (r/solar)
- reddit.com/r/electricians/comments/8lm9ou/
- reddit.com/r/solar/comments/1ejmsau/
- reddit.com/r/solar/comments/18zrbij/
General guidance based on the manufacturer's manual or the named source. Always follow the current manual for your exact model and your national code. DC and AC electrical work is for qualified installers only. Not affiliated with or endorsed by any brand named; trademarks belong to their owners.