What the K-curve means for your load
The K-curve trips between 10 and 14 times rated current — a tighter magnetic-trip band than the D-curve (10–20× In) but wider than C-curve (5–10× In). That makes the S281UC-K20 a good fit for motor-starting loads, transformers, and other inductive circuits where inrush current is higher than a C-curve can handle but you still want better selectivity than a D-curve gives. On a pump or small conveyor drive, this breaker keeps the branch protected without nuisance tripping on the start.