The MGN61370 is a 1-pole Multi9 C60 miniature circuit breaker rated 4 A at 25 °C with a C-curve magnetic trip threshold of 8.5 x In (±20% on AC). Breaking capacity is 10 kA at 277 V AC under UL 489, CSA C22.2 No 5.2, and IEC 60947-2. Overvoltage category IV and pollution degree 3 confirm it's rated for the main distribution board, not just sub-panel use. Clip-on DIN rail mount, 18 mm per pole (2 x 9 mm pitches), with ring-terminal connections torqued to 2 N·m. The IP40 modular enclosure protects against tools and small wires entering the front face; IP10 at the terminals means the wiring compartment is open enough that you don't crowd conductors. Padlockable handle for lockout/tagout compliance.
Carries UL 489, CSA C22.2 No 5, EN/IEC 60947-2, and GB 14048.2 approvals — accepted in North American, European, and Chinese installations without additional certification work. Rated for 50/60 Hz networks, tropicalisation class 2 per IEC 60068-1 (handles 95% relative humidity at 55 °C), and operating altitude up to 2000 m without derating. Electrical durability of 10,000 cycles and mechanical durability of 20,000 cycles — the mechanical figure governs handle life in frequent-switching applications like lighting contactor replacement.