RCCB-ID – 125 A, 100 mA, Type AC, 4P
The Schneider Electric A9R12492 is an Acti9 RCCB-ID residual current circuit breaker rated for 125 A continuous current at 400 V AC, 50 Hz, with 100 mA earth-leakage sensitivity and Type AC detection (sinusoidal AC residual currents only). It is a 4-pole, instantaneous-trip device (no time delay) built to IEC/EN 61008-1 and IEC/EN 61008-2-1, carrying VDE quality mark.
125 A rated current means this RCCB handles the full load of a large submain or a high-demand outgoing feeder in a 400 V three-phase distribution board. The 100 mA sensitivity is a common choice for general-purpose earth-fault protection where nuisance tripping from normal leakage (cables, filters, small loads) must be avoided — typical for circuits supplying fixed equipment rather than socket outlets. Type AC detection covers sinusoidal AC residual currents; it does not detect pulsating DC or smooth DC residuals, so it is not suitable for circuits with electronic loads (VFDs, switched-mode supplies, single-phase rectifiers) that generate non-sinusoidal leakage. Breaking capacity is rated at Im = 1250 A at both 400 V and 230 V — this is the making and breaking capacity for the integrated switching contacts under fault conditions.
Snaps onto a 35 mm symmetrical DIN rail, 4-pole wide (72 mm width, 86 mm height, 76 mm depth). Tunnel-type terminals accept up to 50 mm² rigid or 35 mm² flexible cable per pole; two smaller conductors (1.5…16 mm²) can be paralleled. Tightening torque is 3 N·m. The IP20 rating suits enclosed distribution boards; the modular enclosure achieves IP40 inside the panel.