The A9KR16440 is a Schneider Electric Acti9 ID K residual current circuit breaker (RCCB) — 4 poles, rated 40 A, with 300 mA earth-leakage sensitivity, Type AC, for 380...415 V AC 50 Hz networks.
Rated 40 A continuous load. 300 mA sensitivity for group protection, not personnel. Rated operational voltage is 380...415 V AC, 50 Hz — standard for three-phase four-wire systems in many European and Asian markets. The breaking capacity (Idm 500 A, Im 500 A) is the short-circuit withstand of the RCCB itself; upstream protection (MCB or fuse) must coordinate to keep fault current below that level. Voltage-independent tripping means the RCCB detects leakage and trips even if the phase voltage is lost — a safety advantage over electronic RCDs that need a power supply. Instantaneous trip (no time delay) means it reacts within a few cycles; for selectivity with downstream RCDs, a time-delayed (S-type) version would be required.
Clip-on mounting on DIN rail, 4-pole, neutral on the left. Width is 72 mm (8 x 9 mm pitches). Tightening torque 3.5 N.m. Strip length 14 mm. IP20 on the body, IP40 inside a modular enclosure.