Rapid Shutdown Device: Module-level RSD on String B

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.