The Siemens SENTRON 5SU1444-1RC40 is a 40 A, 4-pole RCBO (residual current operated circuit breaker with integral overcurrent protection) in a 7-module-wide housing. It combines a C-curve MCB with a Type AC 100 mA residual current device in one unit, saving a DIN-rail position compared to separate devices.
Rated breaking capacity is 10 kA per EN 60898 and 15 kA per IEC 60947-2 at 415 V AC. The higher IEC figure means this RCBO can sit downstream of a transformer or main breaker with up to 15 kA prospective fault current — common in industrial sub-distribution boards. For residential or light commercial panels where the upstream device limits fault current to 10 kA, the EN 60898 rating applies.
Occupies 7 modular width units (126 mm) on a DIN rail. Depth is 70 mm, height 90 mm — standard for SENTRON RCBOs. The IP20 rating applies only when the distribution board is installed and conductors are connected, so the board enclosure provides the environmental seal. Rated for 50 Hz operation only — not suitable for 60 Hz networks.