Siemens 5SL4250-6CC Miniature Circuit Breaker, 400V 10kA, 2-

The Siemens 5SL4250-6CC is a 2-pole miniature circuit breaker rated for 400 V with a 10 kA interrupting capacity, B-curve trip characteristic, and 50 A current rating. This is the part you need when a 50 A branch circuit on a 400 V line needs short-circuit and overload protection — the 10 kA breaking capacity tells you it can safely interrupt a fault up to that level without welding its contacts shut or cascading the arc upstream to the main breaker. The B-curve (3-5 In instantaneous trip) means it's sized for resistive or general-purpose loads where you want fast clearing on a hard short but can tolerate a brief inrush without nuisance tripping. It belongs to the Basic Devices product family, Group Code P310, Product Group 3822 — that's Siemens' internal classification for standard DIN-rail MCBs in the SENTRON lineup. The DIN-rail footprint means it snaps into the same panel profile as every other 1-module-per-pole breaker; no adapter needed for a standard enclosure.