What the 40 A and Curve K mean for your panel
The ABB S802S-K40 is a 2-pole, 40 A high-performance miniature circuit breaker (MCB) with a Trip Curve K characteristic, rated for 230 VAC and a 50 kA interrupting capacity. The 40 A rating means it protects branch circuits supplying motor loads, transformers, or other inductive equipment where the inrush current is higher than a resistive load — that is what Curve K is designed for. The 50 kA interrupting rating at 230 VAC gives you substantial fault-current headroom, so it can safely clear a short-circuit without upstream coordination issues in most distribution panels. Trip Curve K trips magnetically between 8 and 12 times the rated current (320–480 A instantaneous), which keeps it from nuisance-tripping on motor start-up while still protecting the conductors. That makes it a natural fit for a motor control center or a panel feeding pumps, compressors, or conveyors — the kind of load where a B-curve would trip on inrush and a D-curve might not clear a fault fast enough.
DIN-rail integration and panel fit
Snaps onto standard 35 mm DIN rail per EN 60715. The 2-pole width (2 modules) means it occupies two 18 mm slots in the enclosure — no special adapter needed. Terminal capacity accepts up to 35 mm² conductor, so it handles the feed-through for a 40 A motor circuit without a separate distribution block.