Industrial ST203M-C1NA Solid State Relay Module

ABB ST203M-C1NA is a System Pro M Compact 4‑pole miniature circuit breaker (3P+N) rated 1 A with a C‑curve trip characteristic, designed for distribution panels that require reliable protection of three‑phase circuits with a neutral conductor. It supports up to 10 kA fault-current breaking capacity at typical 230/400 V service and is mounted on a standard DIN rail in ABB System Pro M Compact installations. The unit occupies 4 TE width and accepts conductors from 0.75 to 25 mm² for multi‑conductor runs (0.75–35 mm² for single conductors). This device, referenced in ABB catalogs as ST203M-C1NA (also shown as S203M-C1NA), is commonly used to protect motors, pumps, conveyors, and lighting circuits in industrial and commercial environments, providing coordinated protection across all three phases and the neutral. As part of ABB’s System Pro M Compact line, it is a 1 A, 10 kA breaking‑capacity C‑curve MCCB suitable for panelboard distribution and control applications.