The interrupting curve drops to 121 kA at 415 V and 440 V, and 79 kA at 500 V, so it's built for industrial distribution where fault currents run hot. That matters when you're coordinating with downstream feeders or motor starters and need to ride through inrush without nuisance trips. No undervoltage release, no ground-fault module, no communication function — this is a straight line-protection breaker with a remote-trip option. The 105 mm width and 86 mm depth fit standard SENTRON panel footprints, so it swaps into an existing 3VA cutout without re-drilling gland plates.
Full 63 A rating holds through 50 °C ambient. Above that it starts stepping down: 60.6 A at 55 °C, 58.3 A at 60 °C, 55.9 A at 65 °C, 53.6 A at 70 °C. If your panel sits near hot motor drives or a sun-baked wall, that derating curve tells you whether you need to bump up a frame size. The maximum power loss is 5.4 W, so heat buildup inside a sealed enclosure is manageable — no forced cooling required for a single breaker at full load.
What the ETU320 release gives you
The ETU320 is an electronic trip unit with adjustable overload (Ir) and short-time (Isd) pickup and delay settings. Unlike a fixed thermal-magnetic breaker, you can dial in coordination with downstream devices without swapping trip packs.