The ABB S401M-C63NP is a single-pole miniature circuit breaker from the S400 series, rated at 63 A with a Trip Curve C characteristic and a 10 kA interrupting capacity at 240 VAC.
The single-pole width (one module, ~17.5 mm) keeps panel density high — a 63 A breaker that occupies the same footprint as a 6 A unit. For a cold-storage or freezer panel where every millimeter of enclosure space matters (and where condensation on busbars is a real concern), the compact form factor leaves room for sealed gland plates and thermal breakers. No special busbar comb required beyond standard S400 accessories.