Siemens 5SM1612-0 SENTRON RCCB — 25 A, 300 mA, 2-Pole
The Siemens 5SM1612-0 is a 2-pole residual current circuit breaker (RCCB) from the SENTRON 5SM1 series, rated 25 A at 230 V AC with a 300 mA residual trip. Solid and stranded conductors from 1 to 16 mm² are accepted by the screw terminals, torqued to 2.5–3 N·m.
Thermal Derating and Installation
Rated current holds at 25 A up to 45 °C ambient, then derates linearly to 20 A at 70 °C. That derating curve matters when the RCCB is packed into a crowded DIN-rail enclosure with other heat-generating devices — the 45 °C ceiling is the practical design point; above that, the load must be reduced or ventilation added. Finger and back-of-hand safe protection is built in.