The Siemens 5SY6550-6 is a SENTRON miniature circuit breaker — 2-pole 1P+N, 50 A, B-curve. It's rated 6 kA per EN 60898 and 10 kA per IEC 60947-2, so it handles standard branch-circuit fault levels and still gives headroom for industrial panel SCCR coordination. The B characteristic means it trips between 3 and 5 times rated current — good for resistive and general-purpose loads where you don't want nuisance trips from inrush.
Dimensions and mounting
Two modular width units wide (36 mm), 76 mm deep, 90 mm tall. Snaps onto DIN rail via the quick assembly system; mounting position any. The 70 mm installation depth leaves room behind the gland plate for wiring. Combined terminals top and bottom — wire in and out without extra terminal blocks.
Thermal derating and environment
Full 50 A rating holds at 35 °C. Derate to 47.6 A at 40 °C, 46.35 A at 45 °C, 45.1 A at 50 °C, and 43.75 A at 55 °C. Ambient range -40 to 75 °C, so it's fine in unheated enclosures or near hot equipment. Pollution degree 3, overvoltage category III — suitable for fixed installations in industrial environments. IP20 with conductors connected.
Lifecycle and sourcing
Current production — no end-of-life notice. Standard catalog item in the SENTRON family, specified into BOMs for industrial panels and machine tools.