DC circuit protection with K-curve selectivity
The Schneider Electric MGN61881 is a Multi9 C60H-DC miniature circuit breaker rated 8 A at 50 °C per EN/IEC 60947-2, with a K-curve magnetic trip set at 12 x In ±20 % for DC networks. The 2-pole configuration breaks both legs simultaneously, essential for DC fault clearing where no natural zero-crossing exists. Breaking capacity reaches 20 kA Icu at 250 V DC and 10 kA at 440 V DC, so it handles high-energy battery banks or DC bus faults without cascading upstream. The thermal-magnetic trip unit combines a bimetal for overload protection and a solenoid for short-circuit response. The K-curve characteristic means the magnetic threshold is higher than a standard B or C curve — typically 8 to 12 times rated current — which avoids nuisance tripping on inrush from DC motor drives or capacitive loads while still clearing hard faults. This makes the C60H-DC a fit for DC distribution panels, photovoltaic combiners, and battery-string protection where load inrush is a known factor.
The MGN61881 clips onto standard 35 mm DIN rail (EN 60715) and occupies 4 x 9 mm pitches — 36 mm wide — with a depth of 73 mm and height of 81 mm. Tunnel-type terminals accept up to 25 mm² rigid stranded or 16 mm² flexible, with a strip length of 14 mm and tightening torque of 2.5 N·m. The IP20 finger-safe front and IP40 modular enclosure rating suit enclosed panel mounting; the grey housing includes a padlockable toggle and ON/OFF visual indication. Rated insulation voltage (Ui) is 500 V DC, and operational voltage (Ue) covers 220 V, 250 V, 440 V, and 500 V DC networks.