Equipment
- Inverter: Sungrow SBSE4.8-US-50
- Rapid Shutdown Device: Module-level RSD on String B
- Location: NYC / Con Edison service territory
Error 1: DC Side Error Code 9034
Displayed Message
Error in the rapid shutdown system in String B detected
What this error means
Error 9034 indicates a communication or signal integrity issue between the inverter and the rapid shutdown device. This does not automatically mean a failed rapid shutdown unit or damaged wiring.
Root Cause Identified
- Electrical crosstalk between the inverter and the rapid shutdown device
- Inverter grid monitoring standard was set incorrectly for the installation jurisdiction
Solution Implemented
In the inverter’s device parameters:
- Updated Grid Monitoring Country Standard to
UL1741 / SB Category B-III
This corrected the inverter’s interpretation of rapid shutdown signaling and immediately cleared Error 9034.
Error 2: AC Side Error Code 202
Displayed Message
Grid undervoltage fast
What this error means
Error 202 is triggered when the inverter detects AC voltage that does not match its configured grid profile.
Root Cause Identified
- Incorrect AC grid type selected in inverter settings
Solution Implemented
- Set AC grid type to 208 / 120 V, which matches NYC service
Once updated, Error 202 cleared instantly.
Final Result
- Both Error 9034 and Error 202 resolved without hardware replacement
- System resumed normal operation
- Inverter producing power and communicating normally
Key Takeaway
On Sungrow SBSE inverters, incorrect grid standards can cause false rapid shutdown and grid fault errors. Always verify grid profile and UL category before assuming equipment failure.