V-TAC VT-6605305 Manuel D'instructions page 17

WIRING INSTALLATION
Figure 17 MC4 DC connector and PV string connection
The procedures for connecting PV string t to the inverter DC input are shown below ：
(1) Before connecting PV string to inverter, ensure proper measures against lightening
and short circuit have been taken;
 PV strings can be connected to inverter only after protection measures
which conform to local electrical regulations are taken and the technical
parameters in this manual are fulfilled.
(2) Connect the output cables of solar modules to the DC connector of inverter as Figure
17 shows. Remove the isolation layer of the DC cable for about 8-10mm. Insert the
conductor part into the appropriate position of the connector, crimp the MC4 DC terminal
and tighten the nut with a torque of 2.5-3Nm. Ensure the poles of solar modules are
correctly and well connected with the connectors
(3) After the DC connector is connected, use a multimeter to measure the voltage of the
DC input string, verify the polarity of the DC input cable, and ensure that the voltage of
each string is within the allowable range of the inverter, as shown in Figure 18.
 The PV string connected to the series inverter must adopt the DC connector
configured especially for the inverter, do not use other connection devices
without authorization from our company, otherwise damage to the device,
unstable operation or fire may occur and our company will not undertake
quality assurance or assume any direct or joint liability thereof.