The ABB S201-K5 is a 1-pole miniature circuit breaker from the S200 series, rated 5 A with a K-curve trip characteristic. It's listed as a UL 1077 supplemental protector, meaning it's intended for branch-circuit overcurrent protection within equipment — not as a service-entrance main breaker. The K-curve is engineered for moderate inrush tolerance, typically used on inductive loads like motor starters, solenoid valves, and small transformers where a standard C-curve might nuisance-trip on startup.
Ratings and deployment context
Rated 277 V AC with a 6 kA interrupting capacity, this breaker mounts on standard DIN rail — common in control panels and distribution boards. The single-pole format occupies one 18 mm module, so it fits tightly in crowded enclosures. For a 5 A branch feeding a contactor coil or a small pump motor, the K-curve holds through the magnetizing inrush without opening, but trips fast on hard shorts.
Compliance and approvals
Listed under UL 1077 and CSA 22.2, the S201-K5 is recognized for use in North American industrial control panels as a supplemental protector. The UL 1077 classification means it's not a branch-circuit rated breaker per UL 489, but it's accepted downstream of a UL 489 device for component-level overcurrent protection. RoHS and REACH compliance documentation is standard with the series.