What it is and where it fits
The ABB S203P-K20 is a 20A molded case circuit breaker (MCCB) from the S203P series, designed for panel-mounted overcurrent protection in industrial control cabinets and distribution boards. Rated at 20A, it uses a snap-on DIN rail mount. The K characteristic curve trips faster on short-circuit than B or C curves, aiding selectivity with downstream sub-distribution or motor starters.