Installation and Operating Instructions V01
23
INFORMATION!
If an external residual current device (RCD) is required, refer to the information
below!
If an external residual current device (RCD)
is required in a TT or TN-S system,
install a residual current device which trips at a residual current of 120
mA or
higher.
For each connected inverter, a rated residual current of 120 mA has to be
provided. The rated residual current of the RCD must be equal to at least the sum
of the rated residual currents of the connected inverters. That means that, if, for
example, two transformerless inverters are connected, the rated residual current
of the RCD must be at least 240 mA.
5.4.4 Residual current protection
The inverter is equipped with an all-pole sensitive residual current monitoring unit
(RCMU) with an integrated differential current sensor which fulfills the requirements
of DIN VDE 0100-712 (IEC60364-7-712:2002).
Therefore an external residual current device (RCD) is not required. If an external
RCD needs to be installed because of local regulations, a RCD
type A or type B can be
installed as an additional safety measure.
The all-pole sensitive residual current monitoring unit (RCMU) detects alternating
and direct differential currents. The integrated differential current sensor detects
the current difference between the neutral conductor and the line conductor. If the
current difference increases suddenly, the inverter disconnects from the grid. The
function of the all-pole sensitive residual current monitoring unit (RCMU) has been
tested in accordance with IEC 62109-2.
