It carries a 400 A continuous current rating (In) with an ETU350 LSI trip unit that provides adjustable overload (Ir from 160 A to 400 A) and short-time (Isd 1.5–10 x Ir) plus instantaneous (Ii fixed at 10 x In) protection.
The 400 A frame and 55 kA Icu at 415 V place this breaker in the main or large-feeder position in a low-voltage switchboard. The ETU350 electronic trip offers LSI curves, meaning it can discriminate with downstream breakers on short-time delay — critical for selective coordination in a plant power system.