The Schneider Electric A9R81425 is a 4-pole residual current circuit breaker (RCCB) from the Acti9 iID series, rated 25 A with 30 mA earth-leakage sensitivity. The voltage-independent trip mechanism means it clears a ground fault even if the line voltage has collapsed — no auxiliary supply needed.
The 25 A rated current (In) and 30 mA sensitivity are the two numbers that decide the circuit it goes into. 25 A suits a submains or large final circuit feeding multiple socket outlets or fixed equipment; the 30 mA trip provides fault protection for the wiring and basic additional protection against lethal shock. Type AC earth-leakage protection is the most common and least expensive class, but it will not detect pulsating DC or smooth DC residual currents. If the downstream load includes variable-speed drives, LED drivers, UPS systems, or EV chargers — all of which can generate non-sinusoidal leakage — a Type A or Type B RCCB would be needed instead. For resistive and linear loads (heaters, incandescent lighting, motors without drives), Type AC is correct. Rated insulation voltage 500 V AC, pollution degree 3 (industrial/condensing environments), and IP20 finger-safe terminals (IP40 inside the modular enclosure).
Positioned as an outgoer device in a distribution board. Tightening torque 3.5 N.m top or bottom. Wire strip length 14 mm. The toggle control and padlocking option allow lockout/tagout for safe maintenance. Mechanical endurance 20,000 cycles, electrical endurance 15,000 cycles at AC-1 (resistive load). The 8/20 µs impulse withstand of 250 A per EN/IEC 61008-1 means it survives typical surge events without nuisance tripping.