Design and ratings
The Siemens SENTRON 5SY4150-7KK11 is a 1-pole miniature circuit breaker with a C tripping characteristic, rated 50 A at 35 °C and 230/400 V AC. Temperature derating is specified: 50 A at 35 °C, 47.6 A at 40 °C, 46.35 A at 45 °C, 45.1 A at 50 °C, 43.75 A at 55 °C, and 42.4 A at 60 °C. That means in a warm cabinet — say 50 °C — the breaker's effective continuous current is 45.1 A, not the 50 A label. Plan your load margin accordingly.
The breaker is halogen-free, silicon-free, and sealable. Touch protection is provided. The design is also rated for railway applications, and the product is assigned to function F per IEC 81346-2 and DIN EN 61346-2.
Snap-on DIN-rail mount, any position. The 18 mm width (1 MW) and 76 mm depth leave room for adjacent breakers and wiring ducts.