Reading the order code
The ABB ACS550-U1-038A-4+B055+K462 is a configured ACS550-U1 catalog number with plus-codes +B055 and +K462 layered on the base 038A-4 frame. The plus-code suffix stamps a specific factory build — option content, regional settings, or an added interface — onto an otherwise standard frame, so any swap or second-source has to respect the same suffix string.
