ABB ST203M-K63 Programmable Safety Relay Module

ABB ST203M-K63 is a 3‑pole miniature circuit breaker (MCB) in the ST200M family, rated for 63 A and offering a 10 kA short‑circuit breaking capacity. It uses a K‑curve instantaneous trip profile, providing a moderate fast‑acting protection response for three‑phase circuits. The model is documented with alternate catalog numbers such as ST203M-C63 and ST203M-K63NA to reflect regional variants. Verified distributor listings and ABB catalogs confirm its 63 A, 3P configuration and the 10 kAIC capability, with UL 1077 applicability noted for this type of supplementary protective device in specific markets. This ST203M‑K63 device is designed to protect feeders and distribution circuits in industrial and commercial panel installations, delivering reliable overcurrent protection in compact control and power distribution enclosures.