Sungrow SG3KTL-EC User Manual page 38

5 Electrical Connection
Residual Current Device
With an integrated universal current-sensitive residual current monitoring unit
inside, the inverter is able to distinguish the fault currents from normal capacitive
leakage currents. The inverter will disconnect from mains as soon as a fault current
with value exceeding the limit has been detected.
However if an external RCD or residual current breaker is mandatory, the switch
must be triggered at a failure current of 300 mA or higher.
Requirements of Multiple Inverters in Parallel Grid Connection
If several inverters are operated in parallel connection to grid, different
requirements should be obeyed (See technical information "Technical notes for
multiple-paralleled grid-connected inverters" in the download area of SUNGROW
website).
AC Cable Requirements
The grid is connected to the inverter via 5 wires (L1, L2, L3, N and PE). Feed-in power
is always three-phase via AC terminal at the bottom of the device.
Consider the following facts when selecting AC cables specifications and types:

The grid impedance of the AC cables must correspond to the specification to
avoid unintended disconnection from the grid or derating of the output power.

The maximum cable length depends on the cable cross-section area, as shown in
the following table. Note that the power loss of the cables should be within 1% of
the nominal power.
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User Manual