It carries a 400 A MicroLogic 2.3 electronic trip unit with L-So-I protection curves — long-time overload, short-time short-circuit with fixed delay, and instantaneous — so you get adjustable coordination without swapping trip packs. At 255 x 140 x 110 mm (H x W x D) and IP40 front-face protection, it fits backplate-mounted enclosures where you need front-access cabling on both line and load sides. The IK07 impact rating means it can take a knock during panel wiring or service without cracking the case.
Breaking capacity — what the H suffix buys you
At 240 V it's rated 100 kA Icu, and at 480 V it still holds 65 kA Icu under UL 60947-4-1. For a 400 A frame, that headroom handles most industrial transformer-fed buswork without cascading upstream breakers; you can size the main for selectivity rather than brute-force interrupting rating. The electronic trip unit (MicroLogic 2.3) includes thermal memory — it remembers the last 20 minutes of heating before and after a trip, so a hot reclose won't nuisance-trip on a motor inrush that a cold breaker would handle. That matters on pump or compressor circuits where restarts happen fast.
Mounts flat on the backplate in both horizontal and vertical orientations — no derating for position as long as the 40 °C ambient rating is respected. Six accessory slots (aux contacts, shunt trip, under-voltage release, motor mechanism) can be populated without removing the breaker from the panel. No earth-leakage protection built in — if you need ground-fault on the same frame, you'd step to the MicroLogic 2.3M or add an external Vigi module. The toggle control is manual; no motor operator included, but the six-slot complement allows one to be retrofitted.