Residual current device for 5SY MCB integration
The Siemens 5SM2342-6 is a 4-pole RCD-unit from the SENTRON family, designed as an instantaneous Type A residual current device with a 30 mA trip threshold and 40 A rated current at AC. It mates mechanically and electrically with the 5SY series miniature circuit breakers to form a combined RCBO assembly in a distribution board.
Rated 40 A at AC, the unit derates progressively above 40 °C ambient: 37.2 A at 40 °C and 45 °C, 36 A at 50 °C, 34.8 A at 55 °C, 34 A at 60 °C, 33.2 A at 65 °C, and 32 A at 70 °C. In a crowded enclosure with multiple heat sources, use the 50 °C column (36 A) as the practical continuous rating. The fastening method is standard DIN-rail clip (REG).
The unit withstands a surge current of 1 kA and a surge voltage of 4 000 V, matching the impulse withstand requirements of a standard TN or TT system. Operating frequency is 50 Hz only. The minimum test voltage is 195 V, and the unit includes a protection function against false tripping (nuisance tripping suppression) for transient surge currents that would otherwise cause unwanted disconnection. The OFF-delay time is not adjustable — this is an instantaneous RCD, not a time-delayed (S-type) unit, so it trips within the standard cycle without intentional delay. The rated fault current is also fixed at 30 mA, not adjustable.