The 187 kA breaking capacity at 240 V AC means it can safely clear a fault up to that level without the arc flashing over or the breaker rupturing; at 415 V and 440 V it still holds 121 kA, and at 690 V it derates to 4.25 kA — so for 400 V class systems this breaker sits comfortably in high-fault-current positions like main incomers or bus-tie feeders.
Thermal derating and ambient — the real-world current you can count on
At 55 °C it derates to 154 A, at 60 °C to 148 A, at 65 °C to 142 A, and at 70 °C to 136 A.
The 3-pole design with no auxiliary contact version means you'll need to add an external auxiliary contact block if you want remote status feedback.
What the trip unit does — ETU320 electronic release
The ETU320 is an electronic overcurrent release with LSI protection curves (long-time, short-time, instantaneous). It gives you adjustable pickup and time-delay settings for selective coordination downstream — you can set the short-time delay so a feeder breaker clears a fault before this main breaker trips, keeping the rest of the bus live.