It carries the ETU320 electronic trip unit, which provides adjustable long-time and short-time delay curves plus instantaneous protection — a solid choice for feeder or main breaker duty where selectivity and coordination matter.
The 400 A continuous rating holds flat from 40 °C through 50 °C, then derates to 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. If your enclosure runs hot, you lose 15 % of capacity at the top of the ambient range — factor that into your load budget. Interrupting capacity is 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 7.5 kA at 690 V. Maximum power loss is 96 W at rated current. That heat stays inside the enclosure; make sure your thermal calculation accounts for it, especially in a multi-breaker lineup.
What the trip unit gives you
It supports long-time pickup and delay, short-time pickup and delay (with I²t on/off), and instantaneous pickup.
It mounts via the standard MCCB footprint — four-bolt pattern, rear or front terminals depending on the accessory kit. No DIN-rail clip; this is a bolted-frame breaker for fixed installation in a distribution board or switchgear cubicle.