SMA SC 250U - Manual (Page 8)

Table of Contents SMA America, LLC
8 DISU_SCUS-IA-IUS111711 Installation Guide
6 Electrical connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.1 Overview electrical connections . . . . . . . . . . . . . . . . . . . . . . . . 30
6.1.1 Disconnect Unit for Sunny Central 250U/500U . . . . . . . . . . . . . . . . . . . . . 30
6.1.2 Disconnect Unit for Sunny Central 500HE-US/CA and Sunny Central CP. . 31
6.2 Cable requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
6.2.1 Cable requirements for DC, AC and PE connection . . . . . . . . . . . . . . . . . . . 32
6.2.2 Additional cable requirements for DC connection . . . . . . . . . . . . . . . . . . . . 32
6.3 Connecting DC cables to the Disconnect Unit . . . . . . . . . . . . . 33
6.3.1 Connection sequence DC switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
6.3.2 Connecting DC cables to DC load break switch by screw terminals . . . . . . 36
6.3.3 Connecting DC cables to DC load break switch by cable lugs . . . . . . . . . . 38
6.4 Connecting AC cables to the Disconnect Unit . . . . . . . . . . . . . 40
6.4.1 Additional cable requirements for AC connection . . . . . . . . . . . . . . . . . . . . 40
6.4.2 Arranging AC cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
6.4.3 Overview AC connection to power distribution grid. . . . . . . . . . . . . . . . . . . 42
6.4.4 Overview AC connection to the inverter . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
6.4.5 Connecting AC cables to busbars. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
6.5 Connecting protective earth . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
6.5.1 Additional cable requirements for PE connection . . . . . . . . . . . . . . . . . . . . . 54
6.5.2 Connecting protective earth to busbar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
6.6 Closing the Disconnect Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
6.7 Affixing information about grounded path . . . . . . . . . . . . . . . . 60
7 Operating the Disconnect Unit . . . . . . . . . . . . . . . . . . . . . 61
7.1 Arrangement of the switches. . . . . . . . . . . . . . . . . . . . . . . . . . . 61
7.2 Switching on the Disconnect Unit . . . . . . . . . . . . . . . . . . . . . . . 62
7.3 Switching off the Disconnect Unit . . . . . . . . . . . . . . . . . . . . . . . 63
7.4 Securing against reconnection – Lock-Off function. . . . . . . . . . 64
8 Technical data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
8.1 Disconnect Unit for Sunny Central 250U/500U . . . . . . . . . . . 66