The Siemens SENTRON 5SL4150-7 is a single-pole miniature circuit breaker rated 50 A at 30 °C with a C tripping characteristic. It snaps onto a standard DIN rail, occupies one modular width unit (18 mm), and is specified for residential and infrastructure branch-circuit protection. Breaking capacity is 10 kA per both EN 60898 and IEC 60947-2 at 400 V AC, meaning it can safely interrupt a fault current up to that level without upstream cascading. The overvoltage category is III, suitable for fixed-installation distribution boards.
Derating and real-world current
The 50 A rating holds at 30 °C ambient. At 40 °C it derates to 46.19 A, at 45 °C to 44 A, and at 55 °C to 39.81 A. If the panel runs warm — common in a crowded enclosure — size the upstream conductor and load for the derated figure, not the 30 °C number.
Panel fit and environment
Depth is 76 mm (installation depth 70 mm), height 90 mm, width 18 mm — one standard modular unit. Mounting position is any, which simplifies layout in tight enclosures. The housing is halogen-free and silicon-free, important for environments sensitive to outgassing (clean rooms, medical, or telecom shelters). Sealable with a lead seal for tamper-evident installations. Protection class is IP20 with connected conductors, plus touch protection on the terminals. Degree of pollution 2 (normal, non-conductive). Mechanical service life is 10,000 switching cycles typical.