Rated current and tripping curve
The Siemens SENTRON 5SY4150-8 is a 1-pole miniature circuit breaker rated 50 A at 35 °C, with a D tripping characteristic — meaning it tolerates short-duration inrush currents up to 10–20× rated before opening, suited for motor and transformer branch circuits where high starting currents are expected.
Temperature derating and ambient limits
Rated current steps down as ambient temperature rises: 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. Operating range spans -40 °C to 75 °C, with humidity limits of 95 % up to 55 °C, 55 % up to 70 °C, and 35 % at 75 °C — condensation management matters in outdoor or unheated enclosures.
Mounting and mechanical fit
Width is 18 mm (1 modular unit), depth 76 mm, height 90 mm, installation depth 70 mm.
The part is halogen-free and silicon-free, which simplifies compliance for clean-room or coated-board environments.