Chapter 3: Installing the Inverter
SolarEdge Installation Guide – MAN-01-00057-2.2
Connecting the Strings to the Inverter
Connect the string to the DC input pairs. If required, connect additional strings in parallel using an external
combiner box/branch cables before connecting to the inverter.
NOTE:
Functional electrical earthing of DC-side negative or positive poles is prohibited because the inverter
has no transformer. Grounding (earth ground) of module frames and mounting equipment of the PV
array modules is acceptable.
NOTE:
SolarEdge’s fixed input voltage architecture enables the parallel strings to be of different lengths.
Therefore, they do not need to have the same number of power optimizers, as long as the length of
each string is within the permitted range.
1 Connect the DC connectors of each string to the DC+ and DC- connectors according to the labels on
the inverter.
Figure 11: Inverter DC Connections
Selecting a Residual-Current Device
IMPORTANT SAFETY FEATURE:
All SolarEdge inverters incorporate a certified internal Residual Current Device (RCD) in order to
protect against possible electrocution and fire hazard in case of a malfunction in the PV array, cables
or inverter. There are 2 trip thresholds for the RCD as required for certification (DIN VDE 0126-1-1).
The default value for electrocution protection is 30mA, and for slow rising current is 300mA.
If an external RCD is required by local regulations, check which type of RCD is required for the relevant
electric code. SolarEdge recommends using a type-A RCD. The recommended RCD value is 100mA or
300mA unless a lower value is required by the specific local electric codes. When required by local
regulations, the use of an RCD type B is permitted.
In installations where the local electric code requires the use of a lower leakage RCD, the discharge current
of capacitive parasitic leakage may trip the RCD. Use the following procedure to avoid this problem:
Select an appropriate RCD to ensure proper operation of the installation. A 30mA RCD may still trip
at 15mA (according to IEC 61008). Good quality RCDs will trip at a higher value.
PV modules with low capacitance leakage to the frame are preferable.
For detailed information, refer to the RCD Selection for SolarEdge Inverters Application Note, available on
the SolarEdge website at http://www.solaredge.com/files/pdfs/se-application-rcd-selection.pdf.
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