The ETU320 gives you adjustable thermal and magnetic trip settings, so you can dial in coordination with downstream breakers without swapping trip units.
This MCCB delivers 440 kA interrupting capacity at 240 V, 330 kA at 415 V and 440 V, 220 kA at 500 V, and 52.5 kA at 690 V. Those are the maximum fault currents it can safely clear at each voltage level. The 690 V rating (52.5 kA) is what you'd check for 600 V class Canadian or mining installations.
Thermal performance — it holds 250 A across the board
That's unusual for an MCCB; most frames start dropping current above 40 °C. The ETU320's thermal memory means it tracks prior heating, so repetitive overloads close to the threshold won't sneak through.
The ETU320's adjustment dials are accessible through the front cover without removing the breaker.
Environmental limits
The storage limits are wider because the breaker isn't carrying current — no self-heating to worry about.