The Schneider Electric A9W35263 is an Acti9 Vigi iC60 add-on residual current device (RCD) — a voltage-independent, 2-pole unit rated at 63 A with 300 mA earth-leakage sensitivity. It clips onto the right side of an iC60 MCB via the double-terminal screw connection, turning a standard breaker into a combined RCBO assembly without extra wiring. The Type A-SI (Super Immunised) classification means it handles pulsed DC fault currents and resists nuisance tripping from transient surges or equipment harmonics — a fit for mixed-load panels feeding electronics, VFDs, or LED lighting alongside conventional circuits.
The 300 mA sensitivity and selective time-delay (marked 'S') are the key specs for coordination. Selective delay lets the downstream RCD trip first on a ground fault, keeping this unit as backup — standard practice for fire-protection or main-switchboard RCDs where you want the branch device to clear before the main. The 63 A rating matches the upstream MCB capacity; the voltage-independent tripping technology means the RCD operates without needing a separate power supply, even if the line voltage drops. Rated operational voltage of 230/415 V AC covers single-phase and three-phase distribution in EN 61009-1 circuits. The Type A-SI label adds immunity to high-frequency leakage and 8/20 µs impulse surges up to 3000 A — common in industrial panels with switching power supplies or motor drives. It conforms to IEC 61009-1 and IEC 60947-2 for insulation coordination, with a rated impulse withstand voltage of 6 kV and pollution degree 3. That means it's rated for the dirty, humid conditions typical of an industrial enclosure, not just a clean residential board.
The tunnel-type terminals accept 1…35 mm² rigid or 1…25 mm² flexible cable; strip length 14 mm, tighten to 3.5 N·m. The trip indicator gives a local visual of RCD status without needing to measure.