The Schneider Electric A9F06363 is a 3-pole Acti9 iC60H miniature circuit breaker rated at 63 A with a B-curve trip characteristic. The 15 kA Icu at 380–415 V AC (and 10 kA Icn at 400 V under the domestic standard) gives it solid fault-clearing headroom for most panel applications without cascading upstream.
The 42 kA Icu at 12–133 V AC is the high side for low-voltage secondary taps; the more relevant number for a 400 V panel is the 15 kA Icu at 380–415 V AC (EN/IEC 60947-2) and 10 kA Icn at 400 V (EN/IEC 60898-1). That spread means it coordinates well downstream of a larger moulded-case breaker — you get full selectivity up to its interrupting rating without the nuisance of a main breaker tripping on a branch fault.
Panel integration
Snaps onto standard DIN rail; 54 mm wide (6 x 9 mm pitches) and 78.5 mm deep — fits a standard distribution board without overhang. IP20 rated, so it's for enclosure interiors only — no washdown exposure.
Trip curve and coordination
B-curve means magnetic trip between 3.2 x In and 4.8 x In (4 x In +/- 20 %). The thermal-magnetic trip unit handles overloads on the thermal side and short-circuits on the magnetic side, with a mechanical endurance of 20,000 cycles and electrical endurance of 10,000 cycles.