The MGN60551 is a Schneider Electric C60N miniature circuit-breaker from the Multi9 range, rated 25 A at 50 °C with a D tripping curve. It's a 4-pole unit built to EN/IEC 60947-2, Category A, meaning it's designed for distribution duty where short-circuit protection and isolation are the primary jobs — not motor starting. The D curve (magnetic trip at 12 x In ±20 %) handles high inrush loads like small transformers or lighting ballasts without nuisance tripping.
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 service breaking capacity (Ics) 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 those levels the breaker can be reused, not just replaced. For a 25 A feeder in a 240 V panel with a 20 kA available fault current, this holds. At 415 V you're limited to 10 kA — check your transformer nameplate before specifying.
Snaps onto 35 mm symmetrical DIN rail — 8 module pitches wide (72 mm), 81 mm tall, 73 mm deep. IP20 finger-safe, pollution degree 3. The toggle gives local ON/OFF indication and a contact position indicator confirms isolation status — useful for lockout/tagout verification without pulling the cover.