The ABB OTM63F4C20D380C is a 4‑pole compact automatic transfer switch (ATS) / motorized change‑over switch designed to automatically transfer electrical loads between two independent AC power sources (such as utility mains and a backup generator) in three‑phase systems. It belongs to ABB’s OTM_C20D series, which offers reliable automatic change‑over functionality in industrial, commercial, and critical power applications. The switch supports both automatic operation and manual override and includes mechanical interlocks for safe source isolation, helping ensure continuity of power and protection against simultaneous source connection