The Schneider Electric A9Z24491 is a 4-pole residual current circuit breaker (RCCB) from the Acti9 iID family, rated 100 A with 300 mA earth-leakage sensitivity. It is voltage-independent, meaning the trip mechanism does not rely on the supply voltage to detect a fault — it will still open on a lost neutral or a phase-to-earth fault even when the line voltage has collapsed.
Clip-on mounting on a DIN rail, 72 mm wide (8 x 9 mm pitches). Neutral is on the left. Torque to 3.5 N.m. IP20 finger-safe (IP40 in a modular enclosure). The 73 mm depth fits standard consumer-unit and distribution-board depths.
The instantaneous trip has no intentional delay, so it is the right choice for the main incoming RCCB where you want fastest disconnection; for selectivity with downstream time-delay RCCBs you would need a different variant. Pollution degree 3 rates it for conductive environments typical of industrial panels, not just clean residential boards.