That matters when coordinating with downstream breakers in a selective scheme: you shape the trip to hold through a motor start inrush and still clear a bolted fault fast. Interrupting capacity is the headline number for this frame size: 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V. Communication function is built in, which on the 3VA platform means it can report trip data and status over PROFIBUS or PROFINET via a communication module — useful if you're feeding alarms into a BMS or SCADA without adding separate current transformers.
Thermal derating — no surprise here
That is unusual for an MCCB — most thermal-magnetic breakers start derating above 40 °C. The ETU550 measures current electronically, so ambient temperature inside the panel doesn't shift the trip point.
Depth of 86 mm (3.39 in) leaves room behind a 200 mm deep enclosure for wiring and busbars. The IP40 front means the breaker face is protected against tools and fingers once the panel door is closed.