The Siemens 5SU9356-7CN50 is an RCBO — a residual current circuit breaker with integrated overcurrent protection — combining a 30 mA Type A RCD with a C-characteristic MCB rated at 50 A, all in a single 1P+N module. Type A detection handles sinusoidal AC and pulsating DC residual currents, which covers most modern electronics and variable-speed drives you'd find in a residential or light commercial final subcircuit. The C-curve trips between 5 and 10 times rated current — so 250 to 500 A for this 50 A unit — which suits inductive loads like motor starters, pumps, or small compressors that draw an inrush surge on startup. It's a DIN-rail mount device, so it clips straight into a standard distribution board or panel enclosure alongside other modular devices.
If you're filling a panel or a line-down RCBO swap, this is a live part you can specify with confidence.