The Schneider Electric A9R17440 is a 4-pole Acti9 iID residual current circuit breaker (RCCB) rated for 40 A continuous current with a 500 mA earth-leakage sensitivity. It operates on 380...415 V AC networks at 50/60 Hz and uses voltage-independent residual current tripping technology, so it detects leakage faults without needing an external power supply to the trip coil — a practical advantage when the neutral or phase voltage is compromised. This is a Type AC device, meaning it responds to sinusoidal alternating residual currents. The selective (time-delayed) characteristic means it coordinates with downstream RCCBs — the A9R17440 holds during a short-duration fault to let the closer device clear first, which avoids nuisance tripping of the main feeder in a distribution board.
Occupies 8 x 9 mm pitches (72 mm wide). Depth is 73.5 mm, height 91 mm. Terminals accept 1...35 mm² rigid or 1...25 mm² flexible conductors; wire stripping length is 14 mm, and the tightening torque is 3.5 N.m. IP20 on the body, IP40 inside a modular enclosure — standard for panelboard installation where the enclosure provides the washdown seal.
Electrical ratings and durability
Rated insulation voltage (Ui) is 500 V AC; rated impulse withstand (Uimp) is 6 kV. Breaking and making capacity (Idm/Im) is 1500 A. Electrical durability is 15,000 cycles under AC-1 resistive load; mechanical durability is 20,000 cycles. Pollution degree 3 suits it for industrial control panels where conductive dust or humidity is present. The 8/20 µs impulse withstand of 3000 A (per EN/IEC 61008-1) means it survives surge events common in industrial mains without nuisance tripping.