The Siemens SENTRON 5SM3312-6 is a 2-pole residual current circuit breaker (RCCB) rated 25 A at 40 °C, tripping at 30 mA fault current, Type A, for 230 V AC 50 Hz systems. Type A detection means it catches both sinusoidal AC residual currents and pulsating DC residuals — common from rectified loads like switching power supplies, LED drivers, and variable-speed drives upstream of the RCCB.
Thermal derating and installation
Above that, derate linearly: 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. Depth is 70 mm, which clears most standard 80 mm deep enclosures. The IP20 rating applies only when the distribution board is installed with conductors connected — open-front panels need a cover.