The Schneider Electric A9F08304 is an Acti9 iC60H miniature circuit breaker rated 4 A with a D tripping curve, three protected poles, and a 70 kA ultimate breaking capacity (Icu) at 415 V AC. It's a thermal-magnetic MCB built for distribution boards where high fault currents and inductive loads like small motors or transformers live.
The 78.5 mm depth leaves room in a shallow enclosure for the outgoing cables. Strip 14 mm and you're in business. It's rated for isolation — both EN/IEC 60898-1 and EN/IEC 60947-2 give it the thumbs-up for safe disconnect. The IP20 finger-safe terminals are standard for enclosed gear.
The iC60H carries a 70 kA Icu across the common low-voltage range — 12–133 V, 220–240 V, and 380–415 V AC. At 440 V it's still 50 kA. That's the H suffix: high breaking capacity for a 4 A frame. It's limitation class 3, so it lets through less fault energy downstream, which helps with cascading and selectivity coordination with downstream breakers. For IEC 60898-1 applications the Icn is 10 kA at 400 V. The 60947-2 Icu numbers are the real headroom — useful when you're tying this into an industrial panel with a big transformer upstream.