This International Standard applies to residual current operated circuit-breakers with integral
overcurrent protection functionally independent of, or functionally dependent on, line voltage for
household and similar uses (hereafter referred to as RCBOs), for rated voltages not exceeding
440 V a.c., rated currents not exceeding 125 A and rated short-circuit capacities not exceeding
25 000 A for operation at 50 Hz or 60 Hz.
These devices are intended to protect people against indirect contact, the exposed conductive
parts of the installation being connected to an appropriate earth electrode and to protect
against overcurrents the wiring installations of buildings and similar applications. They may be
used to provide protection against fire hazards due to a persistent earth fault current, without
the operation of the overcurrent protective device.
RCBOs having a rated residual operating current not exceeding 30 mA are also used as a
means for additional protection in the case of failure of the protective means against electric
shock.
This standard applies to devices performing simultaneously the function of detection of the
residual current, of comparison of the value of this current with the residual operating value
and of opening of the protected circuit when the residual current exceeds this value, and also
of performing the function of making, carrying and breaking overcurrents under specified
conditions.