The 187 kA interrupting capacity at 240 V drops to 121 kA at 415/440 V, then to 79 kA at 500 V, and 5.1 kA at 690 V — so the voltage class of your distribution determines which fault level this breaker can clear. At 690 V it's a 5.1 kA device, which means it's suited for low-fault 690 V sub-distribution, not main service entrance at that voltage. The ETU320 is a line-protection (non-selectivity) release — no ground-fault or communication module on this variant. It's the straightforward overcurrent-only trip unit for feeder protection where you don't need zone-selective interlocking or energy-reducing maintenance switching. Thermal derating is published: 250 A through 50 °C, then 241 A at 55 °C, stepping down to 213 A at 70 °C.
Three-pole construction, no auxiliary contact block fitted on this order code.
Integrated undervoltage release — what it means for your safety circuit
No separate shunt trip or UVR module to wire in; it's factory-integrated.