SMA ST6-US - Manual (Page 40)

Electrical connection SMA America, LLC
40 ST36-48US-IA-IUS112321 Installation Guide
Positive grounding
Following figure shows the DC connection with positive grounding.
1. Connect the white wire (PV RETURN) to the terminal labeled DC+ in the Sunny Boy.
2. Connect the black wire (PV HOT) to the terminal labeled DC − in the Sunny Boy.
3. Torque all wires in the terminal blocks inside the Sunny Boy to 18 in lb (2 Nm).
4. Verify that all connections are correctly wired and properly torqued.
☑ The Sunny Boy is DC wired with positive grounding.
5. Repeat steps 1 to 4 for DC wiring with negative grounding for the remaining Sunny Boy
inverters.
Position Description
A White wire (PV RETURN) connected to DC+
B Black wire (PV HOT) connected to DC −
Avoid using wire nuts to join any wires together or to make any connections anywhere in
the PV system. Wire nuts are a frequent cause of unreliable connections, resistive
connections, and ground faults.