What it is and what it does
The Siemens 5SU9356-7KM32 is a 1P+N RCD-operated circuit breaker (RCBO) from the SENTRON 5SU9 family, combining overcurrent protection and residual current detection in a single 36 mm (2 MW) wide module. It is rated 32 A at AC with a C tripping characteristic, meaning it handles moderate inrush from motor or lighting loads without nuisance trips. Breaking capacity is 6 kA per EN 60898 and 10 kA per IEC 60947-2 — the higher figure applies when the device is used as a circuit breaker in industrial distribution per the latter standard.
Type A fault current and where it matters
The Type A fault-current classification means this RCBO detects sinusoidal AC residual currents plus pulsating DC residual currents — the kind generated by single-phase rectifiers in switched-mode power supplies, variable-speed drives, or LED drivers. That makes it the right choice for modern panels where electronic loads are common; a standard Type AC device would miss pulsating DC faults. The device is instantaneous, so it trips without intentional delay, and its energy limiting class is 3, which limits let-through energy during a fault.
Mounting and environmental fit
Snaps onto a 35 mm DIN rail, 36 mm wide (2 width units), with any mounting position accepted. Installation depth is 70 mm; overall depth including terminals is 77 mm. The ambient temperature range is -25 to +45 °C, and derating applies above 40 °C — the rated current drops from 32 A at 30 °C to 27.84 A at 50 °C (–). IP20 protection is standard for installed distribution boards with conductors connected; the enclosure is halogen-free and silicon-free. Solid and stranded conductors from 0.75 to 35 mm² are accepted.