The interrupting ratings are given across system voltages: 187 kA at 240 V, 121 kA at both 415 V and 440 V, 75.6 kA at 500 V, and 3 kA at 690 V. The steep drop to 3 kA at 690 V reflects the ETU550's limits at the top of its insulation voltage (rated 800 V). If your system runs 690 V with high prospective fault current, this isn't the frame for that.
Panel fit and form factor
That 140 mm width on a 4-pole frame is typical for this class — plan your DIN-rail or mounting-plate layout accordingly.
What the ETU550 adds
The ETU550 electronic trip unit provides adjustable long-time, short-time, and instantaneous settings. The communication function allows remote monitoring and trip event logging.
