The Schneider Electric A9W26425 is an Acti9 Vigi iC60 add-on residual current device (RCD) block — a 4-pole, 25 A, 500 mA sensitivity unit with Type A earth leakage protection. It clips onto the outgoing side of an iC60 MCB to add ground-fault detection to the circuit, tripping instantaneously when leakage exceeds the 500 mA threshold. The voltage-independent trip technology means it operates without needing an external power supply, relying on the fault current itself to trigger the mechanism.
Rated at 25 A continuous and 400 V AC (230/415 V AC per IEC 61009-1), this block is sized for a standard 4-pole outgoing circuit in a 50/60 Hz network. The 500 mA sensitivity is for equipment or fire protection where a higher leakage threshold is acceptable. IP20/IP40 protection means installation inside a panel.
The tunnel-type terminals accept 1–25 mm² rigid or 1–16 mm² flexible cable, with a 2 N·m tightening torque and 14 mm strip length. Screw connection to the upstream MCB means it's a mechanical add-on, not a bus-bar jumper; you'll need the matching iC60 breaker and the screws provided.
Designed and certified to IEC 61009-1 and EN 61009-1 (the combined MCB/RCD standard for residual current breakers with overcurrent protection integrated or as an add-on). The 8/20 µs impulse withstand of 250 A per IEC 61009-1 confirms it handles surge currents typical of lightning-induced transients without nuisance tripping.