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.
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. 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.
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.