The A9N21486 is a Prodis Vigi TG40 add-on residual current device (RCD) from Schneider Electric — a voltage-independent earth-leakage block designed to bolt onto a compatible MCB via the screw terminals. Rated 40 A with 30 mA sensitivity, it covers group-incomer or sub-distribution positions where you need combined overcurrent and earth-fault protection in a single DIN-rail footprint.
The 40 A rated current (In) and 30 mA earth-leakage sensitivity are the two numbers that decide whether this block fits your BOM line. 40 A matches a 40 A MCB upstream — the add-on is not a standalone breaker, so it must pair with an MCB of equal or lower rating. Type A-SI (Super Immunised) means it handles pulsed DC fault currents (rectified loads like switching power supplies, LED drivers, VFDs) without nuisance tripping from high-frequency leakage. Voltage-independent tripping — the RCD does not need a separate power supply to detect leakage. That simplifies wiring in retrofit or panel builds where you have only the phase and neutral conductors available. Rated operational voltage is 230 V AC phase-to-neutral at 50 Hz, with insulation rated to 400 V AC.
Clip-on mounting to DIN rail, 18 mm width (1 module), 70 mm depth. Neutral on the left (1P+N configuration). Terminals accept 0.75…16 mm² rigid or 0.33…10 mm² flexible cable; strip length 13 mm, tightening torque 2 N·m. IP20 finger-safe front, pollution degree 3 (conductive pollution typical in control panels). Operating temperature range -25…60 °C, storage -40…60 °C, altitude limit 2000 m.