ABB ST203M-B40 is a three‑pole miniature circuit breaker (MCB) rated at 40 A with a B‑curve trip characteristic, intended to protect three‑phase circuits in electrical distribution panels. The device appears in ABB catalogs as S203M-B40, confirming its 3P 40 A rating and B‑type protection for three‑phase systems. As part of ABB’s compact protection line, this MCB provides reliable overcurrent protection for three‑phase loads in industrial and commercial installations, such as motors and pumps, on standard low‑voltage networks.
