The Schneider Electric Acti9 iID A9R91425 is a 4-pole residual current circuit breaker (RCCB) rated at 25 A with 30 mA earth-leakage sensitivity, Type A-SI (Super Immunised).
The 30 mA sensitivity is the standard threshold for personal protection against indirect contact in residential and commercial circuits — it catches leakage currents that could pass through a human body. The 25 A rated current matches a typical 25 A outgoing feeder; the 4P configuration handles three-phase plus neutral, with neutral on the left per the listing. Rated breaking capacity is 1500 A (Idm and Im), which covers most sub-distribution fault levels. The instantaneous trip time means no intentional delay — it clears a ground fault as fast as the internal solenoid can move. Voltage-independent tripping ensures the RCCB operates even if the neutral is lost upstream, a critical safety feature for personnel protection.
Depth is 73.5 mm, height 91 mm — fits standard modular enclosures. Terminals accept 1–35 mm² rigid or 1–25 mm² flexible; strip length 14 mm, torque to 3.5 N·m. IP20 on the body, IP40 inside a modular enclosure — fine for dry indoor panels, not for washdown zones.