What a 50 A B-curve MCB means on the panel
The 5SP4250-6 is a 2-pole miniature circuit breaker from the Siemens SENTRON 5SP4 family, rated 50 A at 400 V AC with a B tripping characteristic. The 10 kA breaking capacity under EN 60898 tells you it can safely interrupt a fault up to 10 kA at 400 V; the 20 kA rating under IEC 60947-2 gives you headroom if the panel's prospective short-circuit current is higher. Tunnel terminals top and bottom make it straightforward to land solid or stranded copper without ring lugs — a time-saver on a busy panel build.
Mounting and integration notes
Tunnel terminals top and bottom accept conductors without needing bootlace ferrules for stranded wire. No separate neutral pole to wire — it's a 2-pole device, so both phase and switched neutral (or two phases) are broken together.