7
Earthing and current system
The PowerRouter is compliant with the following
earthing systems: TN-S, TN-C, TNC-S or TT.
AC fuse
Nedap recommends that you add a 16 A circuit breaker
with B or (preferably) C characteristics to the AC GRID
line connection between the PowerRouter and the
electric utility meter. We also recommend installing the
same type of 16 A circuit breaker in the AC LOCAL OUT
line connection. It must be possible for the installation
engineer to switch off the circuit breakers to de-
energise the PowerRouter so work on the system can
be performed safely.
RCD rating
PowerRouter type
16 A
PR30S
PR30SB-BS
PR37S
PR37SB-BS
25 A
PR50S
PR50SB-BS
Cable cross section
Nedap recommends you to connect the PowerRouter in the vicinity of the grid connection and use copper
cables with a minimum cross section of 4 mm2. This eliminates unnecessary losses in the internal system and
also prevents voltage disconnects caused by high grid impedance when supplying a high output current.
The diagram below shows that the PowerRouter must increase the AC voltage in order to feed the generated
electricity into the grid. This is because the impedance of the cable to the on-street transformer plays an
important role in this. However, the home installation is connected to the PowerRouter, so the voltage should
never be too high. The PowerRouter software will decrease the output current when this nears the maximum
permissible voltage (cut-off limit). This functionality is added to avoid any unnecessary cut-off in the event of an
ineffective AC grid.
Figure 6: Infl uence of grid impedance on AC voltage
Figure 5: AC connection terminals on the PowerRouter
N
N
L
L
AC GRID
AC LOCAL OUT
NO
NO
NC
NC
250 V
230 V
Street transformer
Grid impedance
20A
20V
1Ω
