The Schneider Electric G12T3F40 is a GoPact MCCB 125 molded case circuit breaker, 3-pole, with a TM-D thermal-magnetic trip unit rated at 40 A at 40 °C. It provides LI protection: the thermal element (L) handles overloads, and the magnetic element (I) handles short-circuits.
Rated operational voltage (Ue) is 415 V AC 50/60 Hz, and rated insulation voltage (Ui) is 440 V AC — both per EN/IEC 60947-2. That covers standard 400 V three-phase distribution networks. Power dissipation is 18.7 W per pole, so total 56.1 W at rated load. That matters for enclosure thermal management — a sealed panel with multiple breakers needs ventilation or derating to stay within the -20 to 55 °C operating range. Electrical durability is 8000 cycles at rated current and voltage; mechanical durability is 30,000 cycles. For a distribution breaker that sees infrequent switching, that is ample.
Mounting and connection
Fixed mounting on a backplate, with front-facing screw terminals for both line and load connections. The toggle control provides manual on/off and tripped indication.