Connecting The Strings To The Connection Unit - SolarEdge SE50K Installation Manual

Connecting the Strings to the Connection Unit

You can connect systems with multiple DC strings in parallel to the DC input terminals of the Connection
Unit.
NOTE
The DC bus of each unit is separate and not shared for all units. Therefore in addition to following the
inverter design rules, each unit should follow the unit design rules as detailed in Technical
Specifications.
Inverters may have a different number of pairs of DC input terminals, depending on the inverter power
rating. If more strings are required, they can be connected in parallel using an external combiner box
before connecting to the Connection Unit; strings connected to different units cannot be combined.
When connecting multiple strings, it is recommended to run separate circuits to the Connection Unit or
to position the combiner box near the Connection Unit.This simplifies commissioning by allowing testing
and servicing near the inverter.
To connect the strings to the Connection Unit with glands:
1. Strip 5⁄16'' (8 mm) of the DC wire insulation.
2. Insert the DC cable from the PV installation, into the DC gland on the Connection Unit.
3. Connect the DC wires to the DC+ and DC- terminal blocks, according to the labels on the terminals.
or; connect two wires (DC+ and DC-) per string:
a. Use a standard flat-blade screwdriver to connect the wires to the spring-clamp terminals. The
screwdriver blade should fit freely in the terminal opening. Too large a blade can crack the plastic
housing.
b. Insert the screwdriver and firmly tilt it to press the release mechanism and open the clamp.
c. Insert the wire into the top opening (see Figure 22).
d. Remove the screwdriver – the wire is automatically clamped.
CAUTION!
Ensure that the Plus (+) wire is connected to the + terminal and that the Minus (-) wire is connected to
the Minus (-) terminal connector.
Extended Power Commercial Inverter Installation Guide MAN-01-00402-1.0
Chapter 4: Connecting the AC and Strings to the Connection Unit
Figure 21: Secondary grounding
31