What it is and what it does
The Siemens SENTRON 5SU9326-1CS63 is a 2-pole RCBO — a combined RCD and MCB in one 4-module-wide unit. It carries a 63 A rated current at 30 °C with a 30 mA residual-current trip, C characteristic for moderate inrush (motor starts, capacitor banks), and a 6 kA breaking capacity certified to both EN 60898 and IEC 60947-2. That 6 kA is the SCCR at the terminals — enough for most final subcircuits in a commercial or light-industrial distribution board, but verify against the prospective fault current at the point of installation.
Ratings that matter for fit
Four width units (72 mm) on a DIN rail — that is the standard 4-MW footprint for a 2-pole RCBO in the SENTRON 5SU9 family. Depth is 77 mm, installation depth 70 mm; the extra 7 mm is the front projection. Mounting position is unrestricted, and the supply can enter from top or bottom, which simplifies panel layout. The IP20 rating means it is protected against finger contact but not against water ingress — it belongs inside a distribution board, not exposed on the line. The C-curve trips between 5× and 10× In, so at 63 A that is 315 A to 630 A magnetic release. The 30 mA residual element is instantaneous (no time delay), which makes it unsuitable for circuits with downstream RCDs unless you coordinate selectivity via a time-delayed S-type upstream. The 1 kA surge withstand (8/20 µs) is typical for this class — it will survive most lightning-induced transients on a TN-S system without nuisance tripping.
Compliance and documentation
Halogen-free and silicon-free construction, pollution degree 2, overvoltage category III. The part is designed to EN 60898 and IEC 60947-2, which means it carries the CE mark for the European low-voltage directive. Touch protection is integrated (finger-safe terminals). Typical mechanical endurance is 10 000 switching cycles.