What this part is and what the ratings mean for fit
The ABB S202-K1 is a 2-pole, 1 A miniature circuit breaker from the S200 series, classified as a supplemental protector per UL 1077 and CSA 22.2. The K-curve trip characteristic means it tolerates short-duration inrush currents typical of inductive loads like small solenoids, relays, and motor starters — it holds through a moderate surge without nuisance tripping, then clears fast on a hard fault. The 6 kA interrupting rating at 277 V AC tells you it can safely break a fault current up to that level without welding contacts or cascading upstream; that's adequate for most control-panel branch circuits fed from a 480Y/277 V distribution. The 1 A rating is the continuous current it carries without heating — sized for a single small load or a control transformer secondary, not for a multi-load string.
Deployment context and panel integration
Snaps onto standard 35 mm DIN rail inside an enclosure — no tools needed for the rail, just a screwdriver for the terminals. The 2-pole width occupies two 18 mm module spaces, so it fits a typical 4- or 8-position distribution block. Rated 277 V AC phase-to-neutral on a 480Y/277 V system; common in North American industrial control panels where a supplemental protector guards a single 120 V or 277 V control circuit fed from a panelboard.
Compliance and approvals
Listed under UL 1077 as a supplemental protector and CSA 22.2 — the standards that govern overcurrent protection for control-circuit and auxiliary loads, not primary feeder breakers. The UL 1077 listing is the key authority signal for North American panel builders: it tells the inspector the part is accepted for its intended role in a UL 508A industrial control panel.