What this breaker does on the rail
The A9F08340 is a 40 A, 3-pole miniature circuit breaker from the Acti9 iC60H series, built for distribution panels where you need a D curve and serious fault-clearing — 42 kA Icu at 12–133 V AC, 30 kA at 220–240 V, and 15 kA at 380–415 V (EN/IEC 60947-2). It's certified to both EN/IEC 60898-1 (household-style MCB standard) and EN/IEC 60947-2 (industrial breaker standard), so it qualifies for isolation duty — the contact position indicator and trip indicator give a visible air gap when it's off. DIN rail mount, 6 x 9 mm pitch (54 mm wide), toggle control, thermal-magnetic trip.
Depth of 78.5 mm, height 91 mm — fits standard DIN-rail enclosures with typical cover clearance. Double terminals top and bottom accept 1–35 mm² rigid or 1–25 mm² flexible; strip 14 mm, torque to 3.5 N·m. IP20 finger-safe on the front, but the terminals are live when connected — standard panel guard rules apply. Earth-leakage protection is via a separate block (Vigi iC60), not integrated.