What this part is and what the ratings mean
The ABB S281-K10 is a 1-pole miniature circuit breaker (MCB) rated 10 A continuous, with a Trip Curve K characteristic, for 480 VAC circuits. It snaps onto a standard DIN rail inside a distribution panel or control enclosure. The K curve means the magnetic trip threshold is set higher than a C-curve — typically 8 to 12 times rated current — so it tolerates the inrush of motor loads, transformers, or solenoid valves without nuisance tripping. That makes it a fit for inductive circuits where a standard C-curve breaker would drop out on startup surge.
How it compares to the S201M-C10
The closest functional peer is the S201M-C10 — also 1-pole, 10 A, DIN rail — but that part uses a C-curve (magnetic trip at 5–10× In) and is rated only 277 VAC / 60 VDC with a 6 kA interrupting capacity. The S281-K10's K-curve and 480 VAC rating give it a wider voltage envelope and better coordination on motor circuits. If your panel was specified around the S201M-C10, the S281-K10 will not drop into the same footprint without checking the voltage rating and trip coordination — same rail, same pole count, but different curve and voltage class.