The ABB S803S-K20 is a 3-pole miniature circuit breaker rated at 20 A with a K trip curve, designed for DIN-rail mounting in distribution panels. The K curve provides a magnetic trip threshold of 10–14× In, making it suited for motor and transformer circuits where inrush current must pass without nuisance tripping. The interrupting rating of 50 kA at 400/690 VAC gives headroom for high-fault installations.
Snaps onto standard 35 mm DIN rail. Rated operational voltage is 400/690 VAC at 50/60 Hz and 375 VDC. The thermal-magnetic trip mechanism handles overload protection via the thermal element and short-circuit protection via the electromechanical element.