Siemens 3VA1 100 A Manual page 349

4. Insert the other end of the connecting cable into the interface <X3 RCD> on the ETU.
The RCD-to-ETU connecting cable is free of silicone and halogen and is electrically isolated
from the main circuits.
The connecting cable is included in the scope of supply.
Tripping
The residual current device utilizes the maglatch of the electronic trip unit (ETU) in order to
trip the molded case circuit breaker. It therefore needs to be connected to the ETU of the
molded case circuit breaker. This connection is made by means of the RCD-ETU connecting
cable.
Use of the residual current device as a pure display unit
The RCD820 residual current device can also operate as a pure display unit without a
tripping function, i.e. it detects and signals residual currents, but does not trip the molded
case circuit breaker or interrupt the circuit.
If the RCD820 device is to operate as a pure display unit, the connecting cable between the
residual current device and the ETU of the molded case circuit breaker can simply be
omitted. With the exception of its communications interface functionality, the residual current
device can perform all its normal functions, e.g. status signaling via LEDs or alarm switches,
etc., in "display mode". Since there is no connection between the RCD and the ETU, the
LED "ACT" flashes continuously and the LED "COM" is not illuminated even if an ETU 5-
series or 8-series is installed.
3VA molded case circuit breakers
Manual, 04/2015, A5E03603177010-02
Accessories
4.8 Residual current devices
349