S202-K2 — 2 A K-Curve Supplemental Protector
The ABB S202-K2 is a 2-pole miniature circuit breaker from the S200 series, rated at 2 A with a K trip curve and 277 V AC. It carries a 6 kA interrupting capacity and is classified as a UL 1077 supplemental protector — meaning it protects downstream equipment, not branch-circuit wiring, so it belongs on the load side of a branch-circuit overcurrent device. The K curve is designed for inductive loads: motors, transformers, and solenoids where inrush current is higher than a resistive load but lower than what a D curve would tolerate.
What the Ratings Mean for Fit
The 2 A rating governs continuous current — this breaker will hold 2 A indefinitely at 40 °C ambient. Above that, the thermal-magnetic trip mechanism responds: the thermal bimetal handles overloads (slow trip, inverse-time), and the magnetic coil handles short-circuits (instantaneous). K-curve magnetic trip is typically 10–14× In, so at 2 A the magnetic pickup is around 20–28 A. That means it tolerates motor starting surges without nuisance tripping, but clears fast on a hard fault. The 6 kA interrupting rating at 277 V AC means this breaker can safely interrupt a fault current up to 6,000 A without welding contacts or rupturing the case. That is adequate for most control panels fed from a 50 kVA or smaller transformer; for larger service entrances, verify the available fault current at the panel. UL 1077 listing means it is a supplemental protector, not a branch-circuit rated breaker (UL 489). In a UL panel, it must be fed from a branch-circuit rated device upstream. CSA 22.2 No. 235 carries the same supplemental classification in Canada.
Panel Integration
Snap-on DIN rail mount, 2-pole width (roughly 36 mm). The S200 series uses a captive screw terminal with box lug — accepts up to 25 mm² conductor. Busbar compatible for feed-through distribution. The K-curve variant is common in motor control centers feeding contactor coils, small transformers, and solenoid valve manifolds.