It is the replaceable protection element that determines the breaker's overload and short-circuit response — not a standalone breaker, but the logic module that snaps into the NSX frame. Rated 32 A at 50 °C with a 3-pole 3D protected-pole configuration, it is sized for distribution circuits in commercial and industrial panels where the breaker frame is already specified. The LI protection curve covers thermal overload (L, adjustable Ir from 0.7 to 1 x In) and fixed magnetic short-circuit pickup at 400 A (Ii). The trip unit mounts in the fixed-mount NSX100/160 breaker; it is not a standalone device. Deployment is inside a panel with IP40 minimum enclosure protection, pollution degree 3 per IEC 60947-1, which is standard for most industrial switchboards.
If your panel ambient runs higher, the breaker must be derated per the manufacturer's thermal curve — the 32 A figure is not a guarantee at 60 °C. This is a standard LI curve for distribution — it coordinates well with downstream branch breakers rated 15-20 A, but verify selectivity with the specific breaker curve before committing the BOM.