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5.10 Input connection (DC)
WARNING – B Check absence of any leakage to ground in the PV generator.
WARNING – B If input strings are paralleled, they must have the same installation conditions (number of panel sets, panel type,
orientation and tilt).
WARNING – B When the photovoltaic panels are exposed to sunlight they provide continuous DC voltage to the inverter. To avoid
risks of electrical shock, all wiring operations must be carried out with the DC disconnect switches (internal (15) and external to the
inverter) and AC disconnect switches (internal (09) or external to the inverter) OFF.
WARNING – B In case presence of internal DC disconnect switch only, there will be live parts internal to the inverter with a consequent
risk of electrical shock. In this case these activity is ONLY allowed with the use of appropriate PPE (overall resistant to electric arc,
dielectric helmet with visor, insulating gloves class 0, Protective overglove in leather EN420 – EN388 , Safety shoes).
WARNING – B The inverters referred to in this document are WITHOUT AN ISOLATION TRANSFORMER (transformerless). This
topology implies the use of isolated PV panels (IEC61730 Class A Rating) and the need to keep the PV array floating with respect
to ground: no terminal of the PV array must be connected to ground. For a different connection of PV strings, when a negative input
grounding kit is installed, the use of an isolation transformer in mandatory. Refer to the “PVS-100/120 GROUNDING KIT“ Quick
Installation Guide for further information
DC input connections may vary depending on the inverter model.
5.10.1 Input connection on standard and S2 models (single/double MPPT)
The connection of the DC input cables on the standard and -S2 models is made on the DC input connection busbar (17) after that the
cables have been passed through the DC cable glands (18).
5.10.1.1 Operations preliminary to the connection of the PV generator
In order to safely perform the preliminary operations before the connection to the PV generator, the connection of the ground protection
cable (10)/(25) to the wiring box is mandatory.
• Checking of leakage to ground of the photovoltaic generator
Measure the voltage present between positive and negative pole of each string with respect to ground.
If a voltage is measured between an input pole and ground, it may be that there is a low isolation resistance of the photovoltaic generator
and the installer will have to carry out a check to solve the problem.
WARNING – B Do not connect the strings if a leakage to ground has been detected, as the inverter might not connect to the grid.
• Checking of strings voltage
Measure the voltage present between positive and negative pole of each string.
If the open circuit voltage of the string is near the maximum value accepted by the inverter, consider that low ambient temperatures cause
an increase in the string voltage (different according to the photovoltaic module used). In this case it is necessary to carry out a check of
the sizing of the system and/or a check on the connections of the modules of the system (e.g.: number of modules in series higher than
the design number).
ATTENTION – A Input voltages higher than the maximum value accepted by the inverter (see technical data table) may occur the
damage of the inverter.
• Checking the correct polarity of the strings
Before wiring the strings, you must ensure that the voltage of each string complies with the correct polarity using a voltmeter.
5.10.1.2 Independent or parallel input channels configuration
The inverter standard and -S2 versions have two input channels (thus benefiting from two trackers for MPPT maximum power point
tracking) which work independently of one another but can be paralleled by leveraging a single MPPT.
Based on PV system configuration, inputs can be set as 2 independent MPPTs or as a single MPPT with the two paralleled input channels.
ATTENTION – A An incorrect setting of the input channels can lead to loss of energy production.
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