The 220 kA breaking capacity at 240 V is the headline number, but out here in the grease what matters is that it holds 154 kA at 415 V and still manages 121 kA at 440 V — that's serious fault-clearing for a motor branch circuit in a 400 V class panel.
Three poles, 800 V rated insulation voltage, and a front IP40 protection class — it's meant for a clean, dry enclosure, not a washdown zone. The thermal derating curve is honest: 40 A flat from 40 °C to 50 °C, then 39 A at 55 °C, 38 A at 65 °C, and 37 A at 70 °C. At 10.8 W maximum power loss, it won't cook the enclosure, but it's not negligible in a sealed box — plan for some airflow if you're stacking several breakers. That three-inch width per pole is standard for a 40 A frame MCCB — it'll drop into a typical panel layout without surprises. It's a straight thermal-magnetic breaker with a trip indicator absent, so you won't get a visual flag on the front when it trips; you'll know by the load dropping out.