The Siemens 5SU9356-1KN63 is a 2-pole (1P+N) RCD-operated circuit breaker from the SENTRON 5SU9 series, combining overcurrent protection and residual current detection in a single 36 mm wide unit. The integrated residual current element detects AC fault currents at 30 mA, providing personal protection against direct contact.
The higher IEC figure applies when the device is installed per the manufacturer's instructions — typically in an industrial distribution board with an upstream backup fuse or MCCB. The energy limiting class of 3 keeps let-through energy low enough to protect downstream wiring.
Above that, derate linearly: 59.22 A at 40 °C, 57.33 A at 45 °C, 54.81 A at 50 °C, and 51.03 A at 55 °C.