Fixed-mount MCCB for distribution panels
The GoPact MCCB 125 order code G12T3F125 is a 3-pole fixed-mount thermal-magnetic circuit breaker with a TM-D trip unit rated 125 A at 40 °C. Rated operational voltage is 415 V AC 50/60 Hz with a breaking capacity of 10 kA at 380/415 V AC, placing it squarely in the T performance level for standard commercial and industrial distribution. Mounting is fixed to a backplate (not DIN rail), with front-front connections via screw terminals and a 25 mm pole pitch. The toggle control gives a clear visual indication of the contact position.
Thermal-magnetic trip and endurance ratings
The TM-D trip unit is factory-set with fixed thermal and magnetic thresholds — no interchangeable rating plugs. The thermal element tracks load current for overload protection (L), while the magnetic coil responds to short-circuit currents (I). This LI protection profile is the standard for general-purpose feeder and branch-circuit protection in MCCB applications. Mechanical endurance is rated at 30,000 cycles; electrical endurance at 5,000 cycles at rated current and 415 V. Power dissipation is 18.7 W per pole, so at full load the breaker dissipates about 56 W internally — factor that into panel thermal design, especially in sealed enclosures.