The Schneider Electric A9R56240 is an Acti9 iID K residual current circuit breaker (RCCB) — 2 poles, rated 40 A continuous, with a 300 mA earth-leakage sensitivity. The Type AC detection handles sinusoidal residual currents; the trip is instantaneous and voltage-independent, so it works even if the neutral is lost.
The 40 A rated current (In) matches a typical 40 A feeder or submain — sized for a 9 kW resistive load at 230 V or a motor circuit with appropriate upstream coordination. The 300 mA sensitivity is a common choice for protection against fire risk from earth faults, not personnel shock (that would be 30 mA or lower). Type AC means it trips on sinusoidal AC residual currents only; if the load includes rectifiers, VFDs, or switched-mode supplies that generate pulsed or DC fault currents, a Type A or Type B RCCB would be needed instead. Rated conditional short-circuit current (Inc) is 4500 A — the maximum prospective fault current the device can withstand when backed by an upstream overcurrent protective device. Pollution degree 2 covers normal indoor environments. Mechanical durability is 5000 cycles; electrical durability (AC-1 resistive load) is 2000 cycles. That's typical for an RCCB used as a main switch or in a seldom-operated feeder — not a daily-switched contactor duty.
The device occupies 4 modules of 9 mm pitch (36 mm total width). Neutral is on the left. Tunnel-type terminals accept 1–35 mm² rigid or 1–25 mm² flexible cable; strip length is 16 mm. IP20 on the body, IP40 inside a modular enclosure.