The Schneider Electric A9Q44240 is an add-on residual current device (RCD) from the Acti9 Vigi iC60 series, designed to clip onto the side of an iC60 miniature circuit breaker. It adds earth-leakage protection to the outgoing circuit without needing a combined RCBO unit. The 40 A rated current and 300 mA sensitivity suit it for general-purpose protection on lighting, socket, or small-power circuits where the primary concern is fire prevention rather than personal shock protection (which typically requires 30 mA). Rated operational voltage is 230...415 V AC at 50/60 Hz, covering single-phase and three-phase applications up to 415 V line-to-line. The voltage-independent tripping technology means the device operates without needing a separate power supply — it uses the fault energy itself to trip, so protection is maintained even if the neutral is lost upstream.
Mounting and integration with the MCB
The 73.5 mm depth is the same as the iC60 breaker, so it fits existing enclosures without extra clearance. A comb busbar can feed the bottom terminals — the block is marked as bottom-compatible for busbar distribution.
Protection characteristics and standards
The sensitivity is 300 mA, instantaneous (no intentional time delay). This is typical for fire-protection RCDs on circuits where nuisance tripping from equipment leakage (e.g., VFDs, UPS) is a concern, but note it does not detect pulsating DC or smooth DC faults — for those, a Type A or Type B device is required. Compliant with EN/IEC 61009-1 and EN/IEC 61009-2-1 for RCBOs (residual current operated circuit-breakers with integral overcurrent protection) — though this is the add-on block only, the combination with an iC60 MCB forms a functional RCBO. Rated impulse withstand voltage is 6 kV (IEC 60947-2), pollution degree 3. IP20 on the device body, IP40 inside a modular enclosure.