The ABB S801U-K80 is a 1-pole miniature circuit breaker from the S800 series, rated 80 A at 240 VAC with a Trip Curve K characteristic. The 80 A continuous rating sets the thermal-magnetic trip threshold for overload protection; the K curve means the magnetic trip operates between 10x and 14x rated current, which is deliberately higher than a C curve (5x–10x) but lower than a D curve (10x–20x). This makes the K curve a good fit for circuits with moderate inrush — motor starters, transformer primaries, or lighting banks where the starting surge is above a C curve's tolerance but doesn't need the full headroom of a D curve.
Snaps onto standard DIN rail — the S800 family uses the same 35 mm profile as the bulk of panel-mounted breakers. Single-pole format means it occupies one module width (roughly 17.5 mm per pole), so a 1-pole unit takes a single 17.5 mm slot. Terminal capacity handles conductors up to 35 mm² for the line and load sides, per the S800 terminal spec. For a panel OEM or MRO planner, the DIN-rail footprint and single-pole layout let you swap this into an existing S800 or compatible rail without re-drilling or re-wiring the backplane.