The Siemens 5SL4405-8CC is a 4-pole miniature circuit breaker rated 400 V with a 10 kA breaking capacity and a D tripping characteristic at 0.5 A. The D-curve means it tolerates the high inrush currents typical of motor loads, transformers, or solenoid valves — it won't nuisance-trip on startup, but clears a hard fault fast. That 10 kA SCCR at 400 V is the maximum fault current the breaker can safely interrupt without welding contacts or cascading upstream; it's sized for standard distribution panels in commercial and light industrial builds.
Snap-on DIN rail mount, 4-pole width. The 0.5 A rating suits a small control transformer primary or solenoid bank drawing under half an amp. Watch ambient temperature derating in a crowded enclosure.