The Schneider Electric A9Y81640 is an Acti9 Vigi iC40 add-on residual current device (RCD) designed to clip onto the outgoing side of a compatible MCB, providing earth-leakage protection in a compact 1P+N module that occupies two 9 mm pitches (18 mm total) on a DIN rail. The tripping mechanism is voltage-independent, so it operates regardless of whether the supply voltage is present — a key safety feature for circuits where a neutral loss could otherwise blind a conventional RCD.
Rated operational voltage is 230 V AC at 50/60 Hz, with an insulation voltage of 400 V AC and impulse withstand of 4 kV — this covers standard single-phase final circuits in residential, commercial, and light industrial distribution boards. Earth-leakage protection is instantaneous (no intentional time delay), so it trips within 300 ms under fault conditions — suitable for circuits where nuisance tripping from transient surges is not expected, and where rapid disconnection is required for personnel protection. The device is rated for pollution degree 3 (conductive or dry non-conductive pollution that becomes conductive due to condensation — typical in industrial enclosures without climate control), and operates from -25 °C to 60 °C ambient, with storage from -40 °C to 85 °C.
Mounts via clip-on to a DIN rail, with the neutral on the left side of the module. The bottom tunnel terminals accept 1 to 16 mm² rigid or 1 to 10 mm² flexible conductors; wire stripping length is 14 mm, tightening torque 2 N·m. Electrical connection to the upstream MCB is by screws — the Vigi iC40 is an add-on block, not a standalone RCCB, so it must be mechanically and electrically coupled to a compatible Acti9 MCB (same brand, same series) to form an RCBO assembly. IP20 rated (finger-safe) on the front, IP40 within the modular enclosure — standard for installation inside a distribution board; no outdoor or washdown exposure without additional enclosure protection.