The ABB S254S‑D16 is a 4‑pole miniature circuit breaker (MCB) from ABB’s System pro M compact S200 series, designed to provide reliable overload and short‑circuit protection in low‑voltage electrical distribution systems. It features a Type D thermal‑magnetic trip characteristic, making it suitable for circuits with high inrush currents, such as those feeding motors, transformers, and inductive loads. The breaker mounts on a standard DIN rail (TH35) and offers clear ON/OFF toggle indication, compact modular construction, and robust performance for residential, commercial, and industrial applications. It can also be equipped with accessories such as auxiliary contacts or shunt trips to expand functionality.