The Schneider Electric A9R88240 is a 2-pole residual current circuit breaker (RCCB) from the Acti9 iID K series, rated at 40 A with 30 mA earth-leakage sensitivity.
Clip-on mounting to a DIN rail, 36 mm wide (4 x 9 mm pitches), 85 mm tall, 69 mm deep. Neutral on the left. Tunnel terminals accept up to 35 mm² rigid or 25 mm² flexible, with a 16 mm strip length and 3.5 N·m torque. IP20 body, IP40 inside a modular enclosure — standard for a distribution board or consumer unit. Padlocking provision for lockout/tagout.
Rated insulation voltage is 440 V AC, impulse withstand 4 kV, pollution degree 2. The voltage-independent tripping technology means the device does not need an external power supply to detect and clear a residual current fault — it derives the trip energy from the fault itself, so it remains functional even if the line voltage drops.