The SENTRON 5SM1342-0 is a 4-pole residual current circuit breaker (RCCB), Type AC, rated 25 A with a 30 mA trip threshold at 400 V AC. It snaps onto DIN rail (REG) and fits any mounting position, making it a straightforward swap in a standard panel enclosure. The IP20 rating applies once the distribution board is installed with conductors connected — normal for a panel-mounted device.
At 40 °C and 45 °C the device holds its full 25 A rating. Above that it derates: 23.5 A at 50 °C, 22 A at 55 °C, 20.5 A at 60 °C, 19 A at 65 °C, and 17.5 A at 70 °C. Short-circuit rating is 10 kA per IEC 61008-1 and 0.8 kA per EN 60898. The 10 kA figure governs the fault-withstand capability at the device terminals; the EN 60898 value is the rated breaking capacity under that standard's test sequence. For most panel applications the 10 kA SCCR is the number to coordinate with upstream protection.