The Siemens 5SM3344-0LA is a SENTRON 4-pole residual current operated circuit breaker (RCCB), type AC, rated 40 A with a 30 mA trip threshold at 400 V AC. It includes thermal overload protection and is designed for instantaneous tripping on AC fault currents.
The 30 mA residual current trip is the standard for personnel protection in most IEC-based installations — it catches leakage through a human body to ground. The 10 kA SCCR at 400 V matches typical domestic and commercial fault levels; verify coordination with the upstream MCB or fuse.
Mounts on DIN rail (REG profile) in any position — no orientation restriction. The screw terminals accept solid or stranded conductors from 1.5 to 25 mm²; tighten to 2.5–3 N·m.
Finger and back-of-hand safe touch protection. Silicon-free construction. Ambient storage range -40 to +75 °C; operating range -5 to +45 °C. Mechanical service life 10 000 switching cycles typical.