What this 400 A MCCB delivers for a main feeder
At 240 V it interrupts 242 kA, and the rating holds at 187 kA through 415 V and 440 V, then steps to 121 kA at 500 V and 40 kA at 690 V — that kind of headroom means it handles high-fault service entrances without cascading upstream. The 400 A rating stays flat from 40 °C up to 50 °C; above that it derates linearly, hitting 340 A at 70 °C, so the thermal curve is predictable for a warm panel.
Trip unit and auxiliary complement
The ETU350 is a programmable electronic trip unit that supports LSIG (long-time, short-time, instantaneous, ground-fault) protection profiles, though this specific variant ships without a ground-fault monitoring module. It includes an undervoltage release (UVR) for coordinated shutdown sequences.