21
EN
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Checking the correct polarity of the strings and Input connection (DC)
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Warning! The inverters to which this document relates to are WITHOUT ISOLATION TRANSFORMER (transformer-
less). This type involves the use of insulated photovoltaic panels (IEC61730 Class A Rating) and the need to maintain
the photovoltaic generator floating with respect to earth: no pole of the generator must be connected to ground.
Comply with the maximum input current relating to the quick-fit connectors as indicated in the technical data.
When exposed to sunlight, the PV panels supply DC direct voltage to the inverter. To avoid risks of electrical shock,
all wiring operations must be carried out with the DC disconnect switches (15), any DC disconnect switches exter-
nal to the inverter (if present, applying LOTO procedures on it), AC disconnect switch (09) and any AC disconnect
switches external to the inverter (applying LOTO procedures on it) to OFF position.
If only the internal DC disconnect switches (15) is present, there will be live parts internal to the inverter with the
conseguent risk of electrical shock. In this case these activities are only allowed by means of appropriate PPE (ove-
rall resistant to electric arc, dielectric helmet with visor, insulating gloves class 0, protective overglove in leather
EN420 - EN399, safety shoes).
For the string connections it is necessary to use the quick fit connectors (16) (usually Weidmüller PV-Stick or WM4, MultiContact
MC4 and Amphenol H4) located on the left side of the wiring box (02).
Refer to the document “String inverter – Product Manual appendix” available at www.abb.com/solarinverters to
know the brand and the model of the quick fit connector. Depending on the model of the connector of the own in-
verter, it is necessary to use the same model and the respective counterpart (check the compliant counterpart on
the website of the manufacturer or in ABB)
Using corresponding parts that are not compliant with the quick fit connector models on the inverter could cause
serious damage to the unit and lead to invalidation of the warranty.
The input connectors are divided into 6 groups (one group for each input chan-
nel) consisting of 4 pairs of quick fit connectors.
For input connectors marked with “A” and “D” you must directly
connect the individual strings coming into the inverter (do not
make field switchboards for parallel strings). This is because the
positive side (19) and negative side (20) string fuses, situated on
each input, are not rated to take strings in parallel (array).
This operation could damage the fuses and consequently could
cause malfunctioning of the inverter.
The connection in parallel of the strings (array composition) could
be made upstream of the input connectors marked with “B” and/or
“C” using a proper Y quick fit connector adapters: in this case the
input fuses will have to be replaced with a suitable size for the par-
alleled strings.
STRINGS POLARITY CHECK AND FUSES INSTALLATION
Check for correct polarity in the input strings and absence of any leakage to earth in the PV generator.
The inside of the inverter may only be accessed after the equipment has been disconnected from the grid and from
the PV generator.
Verify that the string voltage is the same in all the strings that are connecting to the same input channel. Voltage
differences (of the strings connected in parallel) could reduce performance and unwanted opening of the fuses.
The installation must be performed by qualified installers and/or licensed electricians in accordance with the exist-
ing regulations in the country of installation and in accordance of all safety rules for performing electrical works.
These activity is allowed ONLY with the appropriate PPE for carrying out this check (overall resistant to electric arc,
dielectric helmet with visor, insulating gloves class 0, Protective overglove in leather EN420 – EN388 , Safety shoes).
The reverse polarity can cause severe damage.
• Depending of the wiring box (02) version in-
stalled on the inverter there are one or two
boards for the string fuses:
- SX, SY version: contains only positive side
string fuses board (19) and have 24 string fuses
(1 for each strings) that are supplied and have to
be installed.
- SX2, SY2 version: contains both positive side
string fuses board (19) and negative side string
fuses board (20) that totally have 48 string fuses
(2 for each strings). Fuses on the negative side
string fuses board (20) are already fitted while
the fuses on the positive side string fuses board
(19) are supplied and have to be installed.
20
19
6A
6B
6C
6D
4A
4B
4C
4D1D
15
16
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