The A9F08350 is a Schneider Electric Acti9 iC60H miniature circuit breaker, D-curve, 50 A rated current, 3-pole, with a breaking capacity of 42 kA Icu at 12-133 V AC (EN/IEC 60947-2).
The D curve (magnetic tripping limit 12 x In ±20%) means this breaker tolerates high inrush currents — motor starts, transformer energisation, discharge lamps. It won't nuisance-trip on the surge, but clears a hard fault fast. The 50 A rating and 3-pole construction suit a three-phase motor branch or a distribution subfeed. Breaking capacity of 42 kA Icu at 12-133 V AC (and 15 kA at 380-415 V AC) covers most industrial panel fault levels; at 400 V the Icn per EN/IEC 60898-1 is 10 kA, which is the standard domestic/commercial limit. The 500 V rated insulation voltage (Ui) gives headroom for 400 V systems.
Distribution application — panel builders and MRO planners use this MCB in final distribution boards, motor control centres, and sub-distribution for lighting, socket outlets, or small motor loads. The D curve is the go-to for inductive loads that draw a high starting current.