The A9KF71350BQ is a 3-pole miniature circuit breaker from the Schneider Electric Acti9 K60 range, rated 50 A with a C-curve trip characteristic. The thermal-magnetic trip unit combines a bimetal element for overload protection and a solenoid for short-circuit response. The 3-pole configuration protects all three phases of a three-phase AC circuit, so it fits a 3P distribution board or a motor feeder where neutral protection is handled separately.
The 54 mm width (6 x 9 mm pitches) occupies three modular spaces on the rail — standard for a 3P MCB in European-style distribution boards. The 81 mm height and 70 mm depth fit within the envelope of a typical Acti9 enclosure, leaving clearance for wiring ducts and busbar connections. Tunnel-type terminals accept rigid conductors up to 35 mm² and flexible conductors up to 25 mm², both upstream and downstream. The 3.5 N.m tightening torque and 14 mm wire strip length are standard for this class — no special tooling required.
The limitation class 3 rating means it limits let-through energy effectively, reducing stress on downstream equipment during a fault.