The A9F04450 is a Schneider Electric Acti9 iC60N miniature circuit-breaker, 4 poles, rated 50 A with a C curve. It carries a 36 kA Icu breaking capacity at 12–133 V AC, 20 kA at 220–240 V AC, and 10 kA at 380–415 V AC (EN/IEC 60947-2). For distribution duty under EN/IEC 60898-1, the Icn is 6 kA at 400 V AC. The thermal-magnetic trip unit has a magnetic tripping limit of 8 x In ±20 % — meaning it will trip instantaneously on short-circuit currents above roughly 400 A, which is the standard C-curve characteristic for protecting general-purpose loads like lighting, control circuits, and small motor feeders.
Snap-on DIN-rail mounting. The 4-pole width occupies 8 x 9 mm pitches = 72 mm. Depth is 78.5 mm, height 91 mm. Double terminals top and bottom accept 1–35 mm² rigid or 1–25 mm² flexible; wire strip length 14 mm, tightening torque 3.5 N·m. IP20 finger-safe terminals.