ABB, S280 series, K-curve miniature circuit breaker, S281U-K20, 20 A, DIN rail mount.
| Parameter | Value |
|---|---|
| Weight | 0.14 kgs |
The K-curve sits between the C-curve (5–10× In) and the D-curve (10–20× In) in magnetic trip threshold. At 20 A, the S281U-K20 will hold through the startup surge of a small motor or a control transformer but still trip fast on a hard short. For pure resistive loads or long cable runs, a B- or C-curve breaker would be a better selectivity match; the K-curve is the right call when the load has a known inrush profile that exceeds C-curve tolerance.
S281U-K20 is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm commitment.
The S273-K4A is a 4 A three-pole breaker from the same S270 series, so it's not a functional equivalent for a 20 A single-pole need. For a direct replacement, stay within the S280 series at the same 20 A K-curve rating — the S281U-K20 is the single-pole variant.
No — S273-K4A is a three-pole 4 A breaker; S281U-K20 is a single-pole 20 A. They share the same DIN rail footprint but differ in pole count, rating, and curve. Rewiring and possibly a different enclosure knockout pattern would be required.
ABB typically supplies IEC 60898-1 and UL 1077 compliance documentation for the S280 series. Verify the specific markings on the nameplate at receipt to match your local code requirements.