The Siemens SENTRON 5SM3444-0LB01 is a 4-pole residual current operated circuit breaker (RCCB), type AC, short-time delayed, rated at 40 A and 100 mA tripping residual current on a 230 V AC supply. It carries a 10 kA short-circuit current rating and mounts on DIN rail (REG) — a standard fit for distribution boards in residential or light commercial panels.
The 100 mA residual-current trip threshold is set above the 30 mA level used for personal shock protection — this unit is sized for equipment protection or fire-prevention circuits where nuisance tripping from leakage on long cable runs or VFD filters would otherwise be a problem. The short-time delayed design means it withstands brief surge currents up to 3 kA without tripping, coordinating with downstream MCBs so only the faulted branch clears. The 4-pole construction switches all live conductors including the neutral — required for three-phase circuits where a neutral conductor is present.
Designed for DIN-rail (REG) mounting in SENTRON distribution boards. The top-or-bottom feed position simplifies panel wiring. Silicon-free construction suits environments where silicone outgassing can contaminate contacts or optics. Overvoltage category III means it is rated for fixed-installation mains supply — downstream of the service entrance but upstream of socket outlets.