The Schneider Electric MGN60899 is a C60N miniature circuit breaker from the Multi9 range, rated 50 A at 50 °C per EN/IEC 60947-2.
Breaking capacity — what it handles
Rated Icu of 20 kA at 240 V AC phase-to-phase, 10 kA at 415 V, and 6 kA at 440 V — all per EN/IEC 60947-2. The Ics (service breaking capacity) is 75 % of those figures: 15 kA at 240 V, 7.5 kA at 415 V, 4.5 kA at 440 V. That means after clearing a fault at Ics level the breaker is still usable, not welded shut. For a 50 A distribution board fed from a transformer under 500 kVA, this holds.
Snaps onto 35 mm symmetrical DIN rail. Six module pitches wide (9 mm each = 54 mm total). Depth 73 mm, height 81 mm. Tunnel terminals accept 1.5 to 35 mm² — flexible with or without ferrules, or solid. Torque to 3.5 N·m. IP20 finger-safe front; pollution degree 3 rated, so it's fine in a standard industrial panel without sealed enclosures.