The Schneider Electric A9N18355 is an Acti9 C120N miniature circuit breaker (MCB) rated 125 A at 30 °C, 4-pole, with a B tripping curve. It carries dual certification to EN/IEC 60898-1 (MCB standard for household and similar installations) and EN/IEC 60947-2 (low-voltage switchgear standard for industrial applications). That dual rating matters: the 60898-1 rating governs its use as a branch-circuit protector in final distribution, while the 60947-2 rating covers industrial panel applications where higher fault currents or isolation duty is required.
The A9N18355's breaking capacity is specified at several voltage points, each tied to a different standard. Under EN/IEC 60947-2, the Icu (ultimate breaking capacity) is 20 kA at 220–240 V AC, 10 kA at 380–415 V AC, 6 kA at 440 V AC, and 10 kA at ≤500 V DC.
Mounts via clip-on to 35 mm DIN rail. The 4-pole body takes 12 module pitches (9 mm each), so it occupies 108 mm of rail width. Tunnel-type terminals accept 1–50 mm² rigid or 1.5–35 mm² flexible cable; tighten to 3.5 N·m. Wire strip length is 15 mm.