What this part is and what it does
The ABB S202-K8 is a 2-pole miniature circuit breaker from the S200 series, rated at 8 A with a Trip Curve K characteristic. It operates at 277 VAC and carries a 6 kA interrupting rating under UL 1077, classifying it as a supplemental protector rather than a branch-circuit rated device. The DIN-rail footprint means it snaps into standard 35 mm rail inside a control panel or distribution board.
What the ratings mean for fit
The 8 A rating is the continuous current the breaker carries without tripping. Trip Curve K means the magnetic trip operates between 8 and 12 times rated current — that is, between 64 A and 96 A — which is deliberately chosen for loads with moderate inrush, like motor starters, transformers, or solenoid valves. It is not a general-purpose curve; use it where a standard C-curve would nuisance-trip on startup but a D-curve would be too slow for conductor protection. The 6 kA interrupting rating at 277 VAC tells you the breaker can safely clear a fault of up to 6,000 A without welding contacts or rupturing the case. That is adequate for most control-panel secondary circuits fed from a transformer or a 277/480 V lighting panel, but it is not a main service entrance device — UL 1077 supplemental protectors are intended for downstream branch or component protection, not as the service disconnect. Two poles means the breaker simultaneously opens both line conductors. On a 277 V single-phase circuit (line-to-neutral on a 480Y/277 V system), only one pole would be used; the second pole can serve as a switched neutral or remain unused. For a 480 V line-to-line load, both poles are needed.
Compliance and approvals
The S202-K8 carries UL 1077 recognition as a supplemental protector and CSA 22.2 certification. These are the North American approvals that allow installation in UL-listed control panels and industrial equipment. The part is also RoHS and REACH compliant, which covers the EU material restrictions — documentation for all of these is available from the manufacturer upon request.