The Siemens 5SU9356-7KK50 is a SENTRON RCBO — an RCD-operated circuit breaker combining overcurrent and residual-current protection in a single 36 mm-wide module. Rated 50 A with a Type A fault-current sensitivity and tripping characteristic C, it handles the mixed loads common in commercial and light-industrial panels: motor starters, lighting circuits, and socket outlets with electronic equipment that generates pulsed DC fault currents.
Type A detection means this RCBO trips on sinusoidal AC residual currents and also on pulsating DC fault currents up to 6 mA — the kind a half-wave rectifier or a switched-mode power supply can produce. That makes it the right choice for circuits feeding computers, LED drivers, or variable-speed drives where a plain AC-sensitive RCD might not see the fault. Rated current derates with ambient temperature: 50 A at 30 °C, 47 A at 40 °C, 45.5 A at 45 °C, 43.5 A at 50 °C, and 40.5 A at 55 °C. The 1.5 W maximum power dissipation per unit matters when stacking multiple RCBOs on a DIN rail; total heat load adds up fast in a sealed enclosure.
Installation depth is 70 mm; the overall depth is 77 mm including the front projection. Mounting position is any — no restriction on upright or sideways orientation. The supply cord can enter from either top or bottom, which simplifies bus-bar routing in a crowded panel.