User Manual

SMA Solar Technology America LLC 6 Configuration Recommendations and Reference Diagrams
Technical Information RSS-Compability-US-TI-en-10 5
6 Configuration Recommendations and Reference Diagrams
6.1 Important Notes
• If PV subarrays on a roof are separated by distances greater than defined in 2014 NEC 690.12, then at least one
RSB will be required per subarray.
• Two strings can be directly connected to one channel of the SMA RSB if the total module short circuit current is equal
to or less than 36A Isc.
• Each channel has two string inputs. Unused channels should be capped. MC4 caps are supplied with the RSB.
• Per NEC 690.9(A)(b) fuses are not required for two strings. Always consult module manufacturers’ installation
instructions.
Two parallel strings per one SMA MPP input may cause power clipping at full sun conditions. The significance of this
occurrence is inverter, module, and site dependent.
6.2 Reference Diagrams
SMA Sunny Boy Part numbers SBx.x-1SP-US-40
Installed Strings RSB Qty. MPP1 MPP2 MPP3
String per
RSB-1 CH 1
String per
RSB-1 CH 2
21110