The A9Z11240 is a 2-pole residual current circuit breaker (RCCB) from the Acti9 iID family, rated 40 A continuous and 30 mA earth-leakage sensitivity. Voltage-independent tripping means the RCCB breaks on leakage regardless of whether the mains voltage is present — a safety advantage if the neutral is lost upstream. Rated operational voltage is 220...240 V AC at 50/60 Hz, which covers standard single-phase supplies across Europe, Asia, and most 230/400 V three-phase systems when connected phase-to-neutral. Breaking capacity Idm is 1500 A — adequate for downstream fault clearing in a distribution board where the upstream MCB or fuse limits the prospective fault current. The 6 kV impulse withstand voltage (Uimp) and pollution degree 3 rating mean it's suited for installation in ordinary industrial or commercial environments where conductive pollution is possible but not continuous.
Neutral is on the left. Strip length 14 mm, torque to 3.5 N·m. The IP20 body is fine for enclosed distribution boards; IP40 in a modular enclosure keeps dust out.