The Schneider Electric A9R14492 is a 4-pole residual current circuit breaker (RCCB) from the Acti9 range, for outgoing feeder protection in 400 V AC 50 Hz networks. The 125 A rated current (In) handles the main feed for a sub-distribution board or heavy load group. The 300 mA earth-leakage sensitivity (IΔn) is the trip threshold for ground faults. Breaking and making capacity is rated at 1250 A at both 400 V and 230 V, per IEC/EN 61008-1 and 61008-2-1. The rated insulation voltage (Ui) is 400 V AC, matching the operational voltage, so no derating is needed for standard 400/230 V TN or TT systems.
It occupies 8 modules of 18 mm pitch (144 mm total width), so plan for that footprint when laying out the enclosure. The 72 mm width and 86 mm height fit within the usual modular device envelope; depth is 76 mm, which leaves clearance for wiring behind the panel door. Terminals are tunnel-type, accepting up to 50 mm² rigid or 35 mm² flexible cable — sized for the 125 A feed. Tightening torque is 3 N·m; strip length is 11 mm. The red/green trip indicator and padlockable toggle give the commissioning engineer and maintenance crew clear visual status and a way to lock the breaker open for safe isolation.
Designed and tested to IEC/EN 61008-1 and IEC/EN 61008-2-1, the core standards for residual current operated circuit-breakers without integral overcurrent protection. It carries VDE quality label approval, which is the de facto acceptance mark for European electrical installations. The impulse withstand rating is 250 A (8/20 µs waveform), meaning it survives surge events like nearby lightning strikes without nuisance tripping or damage.