The Schneider Electric G12T4F40 is a GoPact MCCB 125 moulded-case circuit breaker, 4-pole, rated 40 A at 40 °C with a TM-D thermal-magnetic trip unit.
For a distribution panel fed by a transformer with a known short-circuit level below 10 kA, this breaker is a direct fit. The TM-D trip unit provides thermal overload protection (L) and magnetic short-circuit protection (I) — no electronic adjustments, just fixed curves. The 4D protected poles mean all four poles are protected, with the neutral pole set to 1 x Ir. Rated operational voltage is 415 V AC 50/60 Hz, and insulation voltage is 440 V AC — both per EN/IEC 60947-2. That covers standard 400/415 V three-phase distribution. Pollution degree 3 allows use in industrial environments with conductive pollution, typical for factory-floor enclosures.
Fixed mounting on a backplate, with front connections both upside and downside. Screw terminals with a 25 mm connection pitch. Mounts horizontally or vertically, flat on the back. Dimensions: 100 mm wide, 130 mm high, 60 mm deep. Neutral is on the left.