The A9KF71363BQ is a 63 A, 3-pole miniature circuit breaker from the Schneider Acti9 K60 series, built to EN/IEC 60898-1 for AC distribution in final circuits. The C-curve (magnetic trip 5...10 x In) means it tolerates moderate inrush from motorized loads or transformers without nuisance tripping — a solid fit for mixed lighting and small-motor panels where the start-up surge is higher than a B-curve would allow. For most commercial and light-industrial distribution boards fed by a transformer of 250 kVA or less, that headroom is adequate. Thermal-magnetic trip technology gives you two protection elements in one package: a bimetal strip for overload (slow, heat-dependent) and a solenoid for short-circuit (instantaneous above the magnetic threshold). The 63 A rating on the thermal element matches the continuous load current of a feeder or a large sub-distribution board.
DIN rail integration and sizing
Snaps onto a standard 35 mm DIN rail (EN 60715) and occupies 6 x 9 mm pitches — that is 54 mm of rail width for the 3-pole body. The 70 mm depth leaves clearance in a standard 120 mm deep enclosure; the 81 mm height fits under a 100 mm cover rail. IP20 finger-safe terminals are fine for enclosed panel use. No earth-leakage protection inside — this is a straight MCB, not an RCBO. If residual current protection is needed on the same circuit, pair it downstream of a separate RCCB or use a combined device.