Asea Brown Boveri ST203M-K60 Molded Case Circuit Breaker

ABB ST203M-K60 is a three-pole molded-case circuit breaker rated for 60 A, designed to protect 3‑phase circuits at 480Y/277 VAC. It uses a thermal‑magnetic trip mechanism with a K‑curve characteristic to provide overload protection and rapid short‑circuit action, helping to prevent damage in motor drives, control panels, and distribution blocks. Listed for North American use as a supplementary protector under UL 1077, this model sits in ABB’s ST200/M family and is suitable for panel and enclosure installations in industrial environments. The ST203M-K60NA variant represents the North American market version, offering a 60 A nominal rating with a compact footprint appropriate for space‑constrained switchgear and control cabinets. Verified specifications include 60 A, 3 poles, operation at 480Y/277 VAC, and a K‑characteristic trip profile, making it a direct choice for protecting branch circuits feeding motors, contactors, and other 3‑phase equipment where reliable, code‑compliant protection is required.