The Siemens 5SY4305-8CC11 is a SENTRON miniature circuit breaker — 3-pole, rated 0.5 A at 400 V AC, with a D tripping characteristic.
Where it fits — panel and application
Installation depth is 70 mm. Terminal range accepts 0.75 to 35 mm² solid or stranded, with a tightening torque of 2.5 to 3.5 N·m. IP20 with connected conductors; sealable, touch-protected terminals. Halogen-free and silicon-free construction. Suitability flagged for mechanical engineering/industry and for railway applications (per the design designation).