The Schneider Electric A9Z25491 is an Acti9 iID 4-pole residual current circuit breaker (RCCB) rated at 100 A continuous, with a 300 mA earth-leakage sensitivity and Type A protection — meaning it trips on sinusoidal AC and pulsating DC residual currents, covering most modern electronic loads like VFDs, UPSs, and switched-mode power supplies that generate pulsed leakage. Rated operational voltage is 380–415 V AC at 50/60 Hz, with a rated insulation voltage of 500 V AC and impulse withstand of 6 kV — solid for standard three-phase distribution in commercial and industrial panels. The selective (time-delayed) characteristic means it coordinates with downstream RCCBs: it holds during short-duration leakage pulses, so only the faulted branch trips, not the main. That's the difference between a single machine down and a whole panel dark.
Occupies a standard 4-module width — plan the DIN rail fill accordingly. Wire stripping length is 14 mm; tightening torque 3.5 N.m. IP20 finger-safe with IP40 in a modular enclosure — fine for enclosed panels, not for wet washdown zones.
Type A + selective: the combination covers modern non-sinusoidal leakage (pulsed DC from electronics) while maintaining coordination with downstream Type A or AC RCCBs. Voltage-independent tripping technology means it works even if the supply voltage drops — no electronic amplifier to fail.