The MGN60553 is a Schneider Electric C60N miniature circuit breaker from the Multi9 range — a 4-pole (4P) unit with a D-curve thermal-magnetic trip, rated 40 A at 50 °C per EN/IEC 60947-2.
That makes this breaker a natural fit for motor branch circuits, welding equipment, or any load with a high starting surge. Breaking capacity is 20 kA Icu 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 the Ics level the breaker can be reclosed and continue service, which matters for uptime in a distribution board where a downstream fault shouldn't force a breaker swap. Rated operational voltage is 440 V AC, so it covers 400 V three-phase networks with headroom. The IP20 finger-safe terminals are fine inside a closed enclosure.