What this K-curve 63 A breaker does for your panel
The ABB S201-K63 is a 1-pole miniature circuit breaker rated 63 A at 277 VAC, with a 6 kA interrupting capacity. The K-curve trips between 8 and 12 times rated current — that's 504 to 756 A instantaneous — making it the right choice for motor-starting and transformer inrush loads where you need to ride through the surge but still clear a hard fault. Snaps onto standard DIN rail, same footprint as any System Pro M compact MCB.
Lifecycle and sourcing posture
This part carries a current lifecycle stage — ABB still lists it as an active catalog number. For BOM freeze or line-down replacement, we source it through our independent distribution network.
DIN-rail integration note
Single-pole format, 17.5 mm per module on standard 35 mm DIN rail. The K63's thermal-magnetic element is self-contained — no external shunt or undervoltage release needed for basic overcurrent protection. Wire range 1–25 mm² for line and load terminals. Torque to 2.5 N·m.