The A9KR11440BQ: The 30 mA sensitivity catches leakage currents that could be lethal or cause arc-flash in a wet or grounded environment. Type AC means it only responds to sinusoidal AC residual currents — not pulsed DC or mixed-frequency waveforms, so it's suited for standard resistive and inductive loads (heaters, motors on line-frequency), not VFD-fed equipment or EV chargers where DC leakage appears. The 40 A rating and 4-pole configuration make it a group incomer for a three-phase distribution board or sub-panel. Instantaneous trip means no coordination with downstream selective RCCBs — it clears immediately on fault. Rated breaking and making capacity is Idm 500 A / Im 500 A — that's the fault-clearing ability under residual current conditions per EN/IEC 61008-1. The 8/20 µs impulse withstand of 200 A means it survives surge events like lightning-induced transients without nuisance tripping. Pollution degree 2 (non-conductive pollution only, occasional condensation) is the standard for enclosed distribution boards.
Installation and wiring
Clip-on DIN rail mounting, neutral on the left. Terminals accept 1-35 mm² rigid or 1-25 mm² flexible (Biconnect top and bottom). Strip length 14 mm, tightening torque 3.5 N.m.