63 A, 3-pole, 15 kA — distribution-grade MCCB for panel builders
The Schneider Electric GoPact MCCB 125 G12E3F63 is a 3-pole molded case circuit breaker rated 63 A at 40 °C, with a TM-D thermal-magnetic trip unit providing L (overload) and I (short-circuit) protection. Its breaking capacity is 15 kA at 380/415 V AC, 50/60 Hz, per EN/IEC 60947-2. The utilisation category A means it's not intended for frequent switching of motor loads; it's sized for distribution feeders and branch circuits where the load is mostly resistive or lightly inductive.
Fixed-mount, front-connect, backplate installation
Mounts fixed to a backplate — no DIN-rail adapter. Both line and load connections are front-facing screw terminals with a 25 mm pitch, so the breaker fits standard panel layouts without busbar rework. Overvoltage category III suits fixed-installation distribution boards.
Thermal-magnetic trip and endurance
The TM-D trip unit is fixed — no interchangeable rating plugs or electronic adjustments. Thermal element tracks RMS heating for overload; magnetic instantaneous pickup is factory-set for short-circuit. Rated for 8000 electrical cycles at rated current and 415 V, plus 30,000 mechanical operations — enough for years of infrequent switching in a distribution panel. Power dissipation is 18.7 W per pole, so three poles total 56.1 W at full load — factor that into enclosure thermal rise calculations.
Rated insulation voltage 440 V AC, operational voltage 415 V AC. Ambient operating range -20 to 55 °C; storage -35 to 85 °C. Altitude derating applies above 2000 m.