Siemens 5SL4450-6 SENTRON MCB — 4-pole, 50 A, B curve, 10 kA
The Siemens 5SL4450-6 is a SENTRON miniature circuit breaker (MCB) with four poles, rated 50 A at 400 V AC, and a B tripping characteristic. It breaks fault currents up to 10 kA per EN 60898 and IEC 60947-2, so it handles standard residential and commercial fault levels without upstream coordination issues. The B curve (3–5× In) makes it a direct fit for resistive and general-purpose loads — lighting, socket circuits, control transformers — where inrush is modest. Four modular width units (72 mm) on a DIN rail, IP20 with conductors connected, and rated for any mounting position.
Thermal derating and ambient range
Rated 50 A at 30 °C; at 40 °C the continuous current drops to 47.36 A, at 45 °C to 46 A, and at 55 °C to 43.09 A. If the panel ambient runs warm — say a crowded enclosure near a drive — size the upstream protective device for the derated figure, not the 30 °C nameplate. The operating range spans -40 °C to +75 °C, with 95% humidity at 55 °C, so it survives outdoor enclosures in cold climates and hot machine cabinets alike.
Panel integration notes
Occupies 4 modular width units (72 mm wide, 90 mm high, 76 mm deep plus 70 mm installation depth). Snap-on DIN rail mount, any orientation. Sealable cover is standard — useful for utility-metering or tamper-proof installations. Halogen-free and silicon-free construction, so it meets clean-room and low-smoke specifications without additional conformal coating. Touch protection integrated; degree of pollution 2, overvoltage category III.