The Schneider Electric A9R54440 is a 4-pole residual current circuit breaker (RCCB) from the Acti9 iID range, rated at 40 A with 300 mA earth-leakage sensitivity. It operates on 380–415 V AC, 50/60 Hz networks, and provides Type A protection — covering sinusoidal AC residual currents and pulsating DC residual currents up to 6 mA, which is the typical waveform from rectifier loads like switched-mode power supplies and variable-speed drives. The RCCB is voltage-independent: it trips on residual current alone, without needing a separate power supply for the detection circuit. This makes it fail-safe against neutral loss scenarios where an electronic trip unit might not operate.
The 40 A rated current (In) defines the continuous load this RCCB can carry. It is intended for outgoing feeder protection in distribution boards. Rated operational voltage of 380–415 V AC covers most three-phase four-wire systems in Europe and Asia. The insulation voltage (Ui) is 500 V AC, meaning the internal clearances and creepage distances are designed for that voltage class — important for coordination with upstream switchgear. The impulse withstand voltage (Uimp) of 6 kV ensures the device survives transient surges common in industrial networks without internal flashover. Breaking and making capacity is rated at 1500 A (Idm and Im). For installations with higher fault currents, an upstream MCB or fuse must limit the let-through energy.
The 4-pole unit occupies 8 modules of 9 mm pitch (72 mm total width). Neutral is on the left-hand side — confirm the busbar or wiring order matches your board layout before termination.