The Schneider Electric A9R40425 is an Acti9 iID K residual current circuit breaker (RCCB) — a 4-pole device rated for 25 A continuous current with a 30 mA earth-leakage sensitivity.
The 30 mA sensitivity is the standard for personal protection against indirect contact in TN and TT systems — it will trip on leakage currents above that threshold instantaneously (no intentional time delay). Breaking and making capacity is 500 A (Idm and Im), adequate for most final-circuit faults in a domestic or light commercial outgoer position. The insulation voltage rating is 440 V AC, and the pollution degree is 2 (normal, non-conductive pollution only). That means it is intended for clean indoor panels — not for outdoor enclosures or environments with condensation or conductive dust without additional enclosure protection. The IP20 body rating (IP40 with modular enclosure) confirms this: it is a panel-mount device, not a standalone outdoor unit.
Strip length is 16 mm; tighten to 3.5 N.m top or bottom. The toggle control gives a clear on/off position, though there is no separate contact position indicator. A padlocking device can be fitted for lockout/tagout. The 8-module width (72 mm) means it takes up a standard chunk of DIN rail — plan your enclosure fill factor accordingly. The electrical durability is 2000 cycles under AC-1 resistive load, and mechanical durability is 5000 cycles — fine for a distribution board that sees infrequent switching, but not rated for daily operational switching duty.