What this RCBO is and what it protects
The Siemens SENTRON 5SU1644-7RC32 is a 4-pole RCBO — a combined residual-current circuit breaker and overcurrent miniature circuit breaker in one 7-module-wide unit. It carries a 32 A rated current with a C tripping characteristic (magnetic release at 5–10× In, typical for motor and lighting circuits with moderate inrush), and a 300 mA Type A residual-current element that detects pulsating DC fault currents as well as sinusoidal AC. That Type A rating matters: it covers the rectified waveforms from single-phase power supplies and VFD front ends, which a plain AC-type RCD would miss.
Breaking capacity and coordination
Rated short-circuit capacity is 10 kA per EN 60898 and 15 kA per IEC 60947-2. The higher IEC figure means this RCBO can be applied in industrial panels where the prospective fault current at the distribution board exceeds 10 kA, provided the installation standard permits the 60947-2 rating. The 4-pole design switches all live conductors including neutral, so it suits TN-S and TN-C-S systems where the neutral must be broken with the phases.
Panel fit and environmental limits
Occupies 7 modular width units (roughly 126 mm) on a DIN rail, with an installation depth of 70 mm. Mounting position is any orientation. Ambient range spans -40 °C to 75 °C, with max 95% humidity — wide enough for unheated enclosures or outdoor-adjacent cabinets. Overvoltage category III and pollution degree 2 suit fixed-installation distribution boards. IP20 applies only when installed in a distribution board with conductors connected; the RCBO itself is not sealed against dust ingress.