The Siemens 5SY4250-8FA is a 2-pole SENTRON miniature circuit breaker with a D tripping characteristic, rated 50 A at 35 °C and 440 V AC. It's listed for mechanical engineering and industrial environments, with IP20 protection once conductors are connected.
The 50 A rating holds at 35 °C; above that, it derates — 47.6 A at 40 °C, 46.35 A at 45 °C, 45.1 A at 50 °C, 43.75 A at 55 °C. If your panel ambient runs warm, size the load accordingly. The breaker is sealable and halogen-free, which simplifies compliance documentation for food-and-bev or clean-room builds.
Mounting and Integration Notes
Mounts in any position — vertical, horizontal, upside down — without derating. No neutral pole switching; this is a straight 2-pole live-only breaker.