The Schneider Electric A9R42225 is an Acti9 iID residual current circuit breaker (RCCB) — a 2-pole, 25 A device with 10 mA earth-leakage sensitivity, Type AC, rated for 230-240 V AC networks at 50 Hz. The 10 mA trip threshold is the key spec here: that's the sensitivity level specified for circuits where direct contact protection matters (bathrooms, outdoor sockets, medical locations in some codes), not the 30 mA general-purpose standard.
The 10 mA sensitivity is the deciding factor for most buyers — standard RCCBs are 30 mA or 100 mA. A 10 mA Type AC device catches sinusoidal AC leakage only; it won't trip on pulsed DC or smooth DC fault currents. If the downstream load includes VFDs, UPS systems, or rectifiers, a Type A or Type B RCCB is needed instead. The voltage-independent tripping technology means the device operates without needing a separate power supply — the fault current itself drives the trip mechanism.
Clip-on mounting on standard DIN rail. Terminals accept 1-35 mm² rigid or 1-25 mm² flexible cable; tighten to 3.5 N·m. Strip length is 14 mm. The IP20 body is fine for enclosed distribution boards; the IP40 modular enclosure rating applies when installed in an Acti9 enclosure.