The A9N18576 is a Schneider Electric Acti9 Vigi C120 add-on residual current device — a 3-pole, 300 mA sensitivity, Type A earth-leakage block rated for 125 A continuous current. It clips onto a 35 mm symmetrical DIN rail and connects to the upstream MCB via screw terminals, making it a straightforward retrofit in an existing Acti9 distribution board.
Rated current is 125 A, operational voltage 230…415 V AC. Sensitivity is 300 mA instantaneous trip. Type A detection covers sinusoidal AC residual currents plus pulsating DC residual currents up to 6 mA of smooth DC superimposed — the standard requirement for circuits with single-phase rectifiers or electronic loads. Pollution degree 3 (IEC 60947-2) means it tolerates conductive pollution in industrial panels where condensation or light dust is expected. The voltage-independent tripping technology means the RCD operates on fault current alone, without needing a separate power supply — it clears a ground fault even if the line voltage is lost. That is a reliability advantage for safety-critical feeders.
Integration notes
The block occupies 10 pitches of 9 mm each (90 mm total width on the rail). Tunnel-type terminals accept 1…50 mm² rigid or 1…35 mm² flexible conductors; strip length is 15 mm and tightening torque is 3.5 N·m.