What it is and what it does
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. The 6 kA breaking capacity (Icn) at 230 V AC means it can safely interrupt a fault current up to 6 kA without welding its contacts or cascading the fault upstream to the main breaker. 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.
Lifecycle and sourcing reality
It's sourced and quoted to order through independent distribution against an RFQ. Availability and current pricing are confirmed at quote time. If you're filling a panel or a line-down RCBO swap, this is a live part you can specify with confidence.