SB in Electrical typically stands for Switch Board, which is a crucial component in electrical systems used to control and distribute electricity to various circuits in a building or facility. This abbreviation is often found in Engineering and Construction disciplines. DC – Direct. Power distribution hierarchy in building. detailed explanation of DB, SDB, MDB, RMU, and Switchgear along with any commonly related equipment you might have missed, including their purpose, application, and hierarchy in an electrical distribution system.