The Schneider Electric A9F03463 is an Acti9 iC60N miniature circuit breaker — 4 poles, 63 A rated current, curve B, thermal-magnetic trip. It's rated for distribution duty in AC and DC networks, with a 36 kA Icu at 12–133 V AC and 10 kA Icu at 380–415 V AC per EN/IEC 60947-2. The 6 kA Icn at 400 V per EN/IEC 60898-1 covers the standard residential/commercial coordination.
The 36 kA Icu at 12–133 V AC covers low-voltage distribution where fault current can spike — a panel fed from a 100 kVA transformer on a 120 V secondary, for example. At 220–240 V it still holds 20 kA Icu, and at 380–415 V it's 10 kA Icu. The 6 kA Icn at 400 V per EN/IEC 60898-1 is the standard domestic coordination. The 4 poles are all protected — no solid neutral. That matters for three-phase plus neutral distribution where you need overcurrent protection on every phase and the neutral. The thermal-magnetic trip unit gives you a fixed thermal curve (B) and a magnetic threshold at 4 x In. Curve B is the least tolerant of inrush among standard curves, so it's the right choice for circuits with predominantly resistive loads or long cable runs where selectivity with downstream MCBs is the goal. The trip indicator and contact position indicator give visual confirmation of state, which saves time during fault-finding or LOTO procedures.
Snaps onto a DIN rail — 9 mm pitch, 8 modules wide (72 mm). That's standard for the Acti9 range; it'll fit any 35 mm rail in a distribution board. Strip length 14 mm. The IP20 finger-safe front is fine for enclosed panels; not rated for washdown. Earth-leakage protection is handled by a separate block — the MCB itself doesn't include RCD functionality. If your circuit needs 30 mA or 300 mA residual current protection, you add a Vigi iC60 or iID block downstream. The MCB's 95 % humidity at 55 °C and pollution degree 3 rating mean it's comfortable in non-conditioned electrical rooms.