15
Connecting the photovoltaic modules
To optimally configure the solar modules, take a look at our PV calculation tool (available online at
www.PowerRouter.com/calculator). You can choose the PowerRouter version and photovoltaic modules you are
using. The calculator tool then calculates the correct string configuration for this combination.
Solar cables
Photovoltaic modules often come with short cable connections (usually Ø 4 mm
2
) with MC4 connectors. If
the total length of the free running cable between the modules and the PowerRouter is less than 50 m, Nedap
recommends that you use a double-insulated solar cable with a diameter of 4 mm
2
. If the length exceeds 50 m,
we recommend you use 6 mm
2
cables.
Warning:
The plus and minus cables must not be run in the same conduit.
Earthing photovoltaic modules
Earthing varies according to the type of photovoltaic module in use and is different for the fixed frame and thin
film types.
The contact protection on the metal frame and the frame surrounding the photovoltaic module has a
considerable bearing on safety. Nedap therefore recommends that you connect the metal frame to earth.
The PowerRouter has an earthing bonding terminal to which an earth cable can also be connected. Since the
photovoltaic section of the PowerRouter is also electrically isolated from the AC part, ESD spikes do not affect
operation of the PowerRouter.
Thin film modules produced by various manufacturers are earthed in different ways; consult the manufacturer’s
specifications. For this type of module, one of the connections must be earthed. Depending on the brand/
manufacturer, it may be the frame or the ‘+’ or ‘-’ terminal that is to be earthed. These photovoltaic modules
will degrade more quickly if they are not connected to earth. The PowerRouter has been designed with this in
mind: it has an earth connection between the photovoltaic connections. Figure 19 provides an overview of the
possible earthing configurations.
In the case of negative earthing, only 1 ‘-’ input needs to be earthed, because the 2 ‘-’ inputs are connected
together inside the PowerRouter. In the case of positive earthing, the special adapted shown in the figure below
must be connected to the two inputs.
Figure 19: Ground connection possibilities for photovoltaic modules
