Siemens 5SU1356-0KV25 FI/LS Protector, Type AC, 30mA, 6kA, 1

The Siemens 5SU1356-0KV25 is an FI/LS combination device — an RCBO — that integrates residual-current and overcurrent protection in a single 1+N-pole module. Rated at 25 A with a B-curve trip characteristic and 30 mA Type AC residual sensitivity, it breaks fault currents up to 6 kA. The 70 mm depth suits standard DIN-rail enclosures; the Type AC designation means it detects sinusoidal AC earth faults only, not pulsed DC or smooth DC — a selection point for circuits with non-linear loads.