ABB ST203M-D63 Programmable Safety Relay Module

ABB ST203M-D63 is a three-pole miniature circuit breaker (MCB) from the ST200M family, designed to protect three-phase circuits in control panels and distribution enclosures when mounted on standard DIN rails. It is rated for 63 A with a D-trip characteristic, offering reliable overload and short-circuit protection for three live conductors fed from a common supply. Electrical ratings specify 240 V AC (125 V DC) nominal operating voltage, with an interrupting capacity of 10 kA at 240 VAC, 5 kA at 480Y/277 VAC, and 10 kA at 125 V DC, making it suitable for a range of industrial electrical networks. The device uses screw terminals for secure wiring and is UL 1077 listed, reflecting compliance for supplementary protection in electrical panels; ABB catalogs list ST203M-D63 under the ST200M series with ordering code 2CDS273334R0631. Typical applications include protection of three-phase motors, machine control circuits, and distribution panels in manufacturing and process environments where a compact 63 A, D-characteristic breaker is desired.