Residual current circuit breakers (RCCBs) disconnect the power supply when dangerously high fault currents occur, thereby protecting people, animals, and equipment. The DRCCB 5 series devices are compact two-pole and four-pole residual current circuit breakers with a self-test function. Type A switches are sensitive to both pulsed and alternating currents. This function is independent of the mains voltage. Switches in the Selftest Restart (STR) version automatically perform a function test of the residual current circuit breaker at regular intervals. This is done without interrupting the system and without additional wiring effort, as the required power supply is integrated. After a trip, the STR performs an automatic reset. Features include: monthly self-test, automatic insulation check before the reset attempt, no reset attempt in case of an existing fault, operational status indication via LEDs, configurable auxiliary contact, mounting type: quick mounting on a mounting rail, installation position is flexible, power supply from above. Application areas: These devices are used wherever electrical systems should not be switched off if possible or are difficult to access. This can include IT systems or telecommunications systems, agricultural facilities, small wind power plants, or wastewater treatment plants. With an optional Modbus interface module, the switching status of the RCCB can be transmitted for remote monitoring.