Features And Application Areas; Rccb - Siemens SENTRON Instructions Manual

Residual current protective devices
4.4

Features and application areas

4.4.1 RCCB

RCCBs are residual current protective devices without integrated protection
against overcurrent (overload and/or short circuit). A corresponding overcurrent
protective device must therefore be assigned to them for overcurrent protection.
The expected operational current of the circuit can be used as a basis for assessing
the level of overload protection needed. The overcurrent protective device must
be selected according to the information provided by the manufacturer of the
residual current operated circuit breaker. In order to meet these requirements
regarding the availability of the electrical installation (see section 5.1.2), final
circuits are to be divided up among several residual current protective devices.
If the protective device trips in the event of a fault or if manual disconnection
is necessary, all the circuits downstream from the RCCB are disconnected from
the power supply, whereby the phase conductor and the neutral conductor are
disconnected. This is an advantage when troubleshooting is carried out in an
installation with fault-laden neutral conductors.
If residual current operated circuit breakers with a rated residual current of 30 mA
or less are used for additional protection, fault protection is to be provided with an
upstream selective residual current protective device with a higher rated residual
current or with an overcurrent protection device. The protective device must be
installed at the beginning of the circuit.
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