The Schneider A9N4P40DGN is a 4-pole 40 A D-curve miniature circuit breaker from the Acti9 xC60 family, rated for 10 kA breaking capacity per IEC 60898-1. The D curve means its magnetic trip operates between 10x and 14x In — designed for loads with high inrush, like small motors, transformers, or discharge lighting where a C curve would nuisance-trip on startup. It's a current-production part, still listed as active on the line.
Snaps onto standard DIN rail in the panel. Four poles wide at 18 mm per pole means it takes 72 mm of rail space — plan the enclosure fill accordingly. The 10 kA breaking capacity at 400 V AC is adequate for most commercial and light industrial sub-distribution boards where the upstream fault level is limited.
Lifecycle stage is listed as current — no end-of-life notice or last-time-buy window on this order code. For a BOM freeze or a panel spec that needs a confirmed active part, this one checks the box without a replacement watch.