The C100N450FM is a 1000 A fixed-mount 4-pole circuit breaker from the ComPacT NS new generation family, fitted with a MicroLogic 5.0 electronic trip unit. The 5.0 provides L (long-time overload), S (short-time short-circuit), and I (instantaneous short-circuit) protection curves — the S curve enables selective coordination downstream, which is what you need for a distribution main or a large feeder where you want the branch breaker to trip first. Rated 85 kA Icu at 240 V AC and 50 kA Icu at 415 V AC per IEC 60947-2, so it handles high fault currents typical of industrial switchboards without cascading failure upstream. The 1000 A trip rating at 50 °C means it carries full load at that ambient; above 50 °C you'll need to derate per the manufacturer's curve. IP40 front face and IK07 impact resistance suit indoor panel installation — not washdown, but fine for a dry electrical room.
Fixed mounting on a backplate, with front connection both top and bottom. Overall dimensions: 327 mm high, 280 mm wide, 147 mm deep — plan for that footprint in your panel layout. Power losses are 22 W at rated current, so factor that into enclosure ventilation.