The 100 A rating holds flat from 40 °C through 50 °C, then derates to 85 A at 70 °C, so it handles warm enclosures without stepping down a frame size. Breaking capacity is the headline number here: 187 kA at 240 V, 121 kA at 415 V and 440 V, 79 kA at 500 V, and 4.25 kA at 690 V. The 690 V figure (4.25 kA) is lower, so check available fault current if you're using this on a 690 V line. That gives you two separate status signals for the panel PLC or indication lamps, plus a dedicated alarm contact that changes state only on a trip — useful for remote fault annunciation without wiring through the aux contacts.
The ETU320 trip unit is the electronic, not thermal-magnetic, type — it gives better accuracy and adjustable trip curves if you need coordination downstream.
What the ETU320 means for coordination
That's typical for a feeder breaker where you need basic overload and short-circuit protection but don't need selective coordination with downstream breakers. If you need short-time delay for zone-selective interlocking, you'd step up to an ETU350 or higher. The 20 000 mechanical endurance cycles (latching) are standard for this class.