63 A, Curve K — the inductive-load breaker for 277 VAC panels
The ABB S203PR-K63 is a 3-pole miniature circuit breaker from the S200PR series, rated 63 A continuous with a Trip Curve K characteristic and a 10 kA interrupting capacity at 277 VAC. Curve K means the magnetic trip threshold sits between 8× and 12× rated current — designed for inductive loads like motors, transformers, and solenoid banks where the inrush spike would nuisance-trip a B-curve but the short-circuit protection still needs to be faster than a Z-curve. The 10 kA SCCR covers most commercial and light-industrial panel fault levels at 277/480 VAC wye.
The manufacturer provides RoHS and REACH declarations with the shipment; CE marking covers the EU low-voltage directive. No UL listing is on record for this exact variant, so verify jurisdictional acceptance if your panel requires UL 489.