Panel-builder's read on the G12E3A100
It's built for distribution duty — category A utilization, meaning it's not intended for motor starting but for line-side feeder or branch protection where you need LI (overload + short-circuit) curves. Screw terminals front-connect both line and load sides, so the wiring pattern stays straight-through — no looping around the back. The 25 mm pole pitch matches the usual busbar or cable-lug spacing.
Push the enclosure ambient to 55 °C and you'll need to derate — the datasheet's thermal curve is the reference, not the nameplate. The TM-D trip unit gives you LI protection: thermal overload (L) adjustable via the dial, magnetic short-circuit (I) fixed at the factory. That's a workhorse combination for general distribution — no ground-fault or electronic curve shaping. The 15 kA at 380/415 V AC is the Icu (ultimate breaking capacity) per IEC 60947-2; the Ics (service breaking capacity) is typically 50-75% of Icu on this class of breaker, so verify coordination if you need full selectivity at the rated fault level.
Mounts on a backplate — no DIN rail adapter. The toggle handle protrudes forward; allow clearance for the arc-chamber venting at the top. Front-connect terminals accept screw-clamp lugs; the 25 mm pitch aligns with standard busbar systems. IP20 finger-safe once installed in an enclosure — the breaker itself is not touch-proof on the live terminals. Power dissipation is 18.7 W per pole at rated current; total 56 W for the 3-pole unit.