The Schneider Electric A9N60789 is a 4-pole miniature circuit breaker from the Acti9 C120 series, rated 80 A at 40 °C with a C curve (magnetic trip at 8 x In ±20 %). The 15 kA Icu breaking capacity at 230…400 V AC, certified to EN/IEC 60947-2, means it can safely interrupt fault currents up to that level without upstream damage — a key number for selectivity coordination studies.
The 80 A rating at 40 °C is the continuous current the breaker carries without tripping in a 40 °C ambient. Above that, the thermal-magnetic trip unit derates — standard practice for panel builders who stack breakers in a warm enclosure. The 15 kA Icu at 230…400 V AC is the ultimate short-circuit breaking capacity — the breaker can clear one fault at that level and still be functional afterward (though you'd replace it after a fault anyway).
Clip-on mounting on 35 mm DIN rail. The 4-pole unit occupies 12 x 9 mm pitches (108 mm wide). Tunnel terminals accept up to 50 mm² rigid cable; tighten to 3.5 N·m. The handle is sealable in ON or OFF position with a 0.7 mm cable for lockout/tagout. IP20 finger-safe front, but the busbar area is live when installed — standard for distribution boards.