The Schneider Electric A9Z35440 is a 4-pole residual current circuit breaker (RCCB) from the Acti9 iID family, rated 40 A with a 300 mA earth-leakage sensitivity. It operates on 380–415 V AC networks at 50/60 Hz, and its Type A-SI (Super Immunised) classification means it handles pulsed DC fault currents and high-frequency harmonics without nuisance tripping — critical on VFD-fed or UPS-backed circuits where standard Type A units can false-trip on switching noise. The selective (time-delayed) characteristic coordinates downstream with instantaneous RCDs, so a fault on a sub-circuit clears before this unit opens, keeping the main bus live.
The 1500 A making/breaking capacity (Idm/Im) handles the inrush of downstream loads on a bolted fault. Voltage-independent tripping means the RCCB operates on residual current alone, no auxiliary supply needed — it clears even if the phase voltage collapses. The 8/20 µs impulse withstand of 3000 A gives it surge immunity against lightning-induced transients on the line.
Mounting and wiring — what to expect at the cabinet
Clip-on mount on standard DIN rail (35 mm). It takes 8 x 9 mm pitch modules (72 mm wide). IP20 body (finger-safe), IP40 inside an enclosed modular panel.