What this MCCB does on the line
The interrupting capacity is the headline: 187 kA at 240 V AC, 121 kA at 415 V, 75.6 kA at 440 V, and still 17 kA up at 690 V. That's serious fault-clearing muscle — it'll interrupt a high-energy arc without the breaker grenading, which matters when you're protecting a transformer secondary or a bus riser where available fault current is north of 100 kA. Thermal derating is published: it carries the full 125 A frame rating up to 50 °C ambient, then drops to 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. If your panel sits in a hot mezzanine or next to a furnace line, that derating curve tells you exactly where you land — no guessing.
If you're mounting it in a cabinet that sees condensation or dust, the enclosure handles the ingress; the breaker itself doesn't need to.
Footprint and panel integration
Dimensions: 101.6 mm wide, 130 mm tall, 70 mm deep — that's a 4-inch by 5.12-inch face, 2.76 inches behind the panel. If you're swapping out an older 3VA or a competitor's 4-pole MCCB in the same amp class, measure the mounting centers first — the 101.6 mm width is compact for a 4-pole 62 A unit, but panel cutouts vary. Power loss at full rated current is 28.1 W maximum. That's not a lot of heat for a 4-pole breaker, but if you're packing several of these in a tight enclosure, add it up — three breakers side by side is nearly 85 W of waste heat that needs to get out. Plan your ventilation or derating accordingly.