Sungrow SG250HX-US, User Manual, Page: 47 / 106

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– Surge protective devices (SPD) for the AC combiner box and on the LV side of the
transformer are recommended to be connected in the "3 +1" manner, as shown in the
figure below. The Min. continuous operating voltages of M1 - M4 are 680VAC.
• The string serial communication box COM100 requires an external power supply of
220Vac, so a power supply port and an input port (including switches) should be re-
served in the LV power distribution room of the boost transformer.
5.7.2 Requirements for OT/DT Terminal
OT/DT terminals (not included in the delivery scope) are required for fixing AC cables to the
terminal block. Purchase the OT/DT terminals according to the following requirements.
OT/DT Terminals of Phase Wire
• Specification: M12;
• Dimensions: a≤46 mm / 13 mm≤b≤15.5 mm / c≤22 mm
OT/DT Terminal of PE Wire
• Specification: M8 / M10.
5.7.3 Connection Procedure
step 1 Open the wiring compartment. For details, refer to " 5.6 Opening the Wiring Compartment " .
step 2 Disconnect the AC-side circuit breaker and prevent it from inadvertent reconnection.
step 3 Install an appropriate conduit, and lead the cable into the cabinet through the conduit.
User Manual 5 Electrical Connection