Product identity and function
The Siemens 5SU1324-1RC40 is a SENTRON-series residual current operated circuit-breaker with integral overcurrent protection (RCBO), rated at 40 A with a C tripping characteristic and 30 mA Type AC residual current detection. It is a 2-pole device occupying 4 modular width units (72 mm wide) for DIN-rail mounting in distribution boards.
Key ratings and their meaning for fit
The 40 A rated current at AC combined with the C characteristic means this RCBO is sized for circuits with moderate inrush — typically motor or lighting loads in commercial or industrial final subcircuits — where the magnetic trip threshold is 5 to 10 times rated current, avoiding nuisance trips on startup. Breaking capacity is rated at 10 kA per EN 60898 and 15 kA per IEC 60947-2. The higher IEC figure applies when the RCBO is used as a circuit-breaker in industrial distribution; the EN figure governs domestic/commercial installations.
Installation and environmental constraints
The device is 72 mm wide (4 MW) and 70 mm deep, fitting standard DIN-rail enclosures.