In AutoCAD MEP 2023 toolset, an electrical project database is a file that contains the panels and circuits to which you assign devices and wires. The electrical project database resides in a file with the file extension of .epd. The devices that make up electrical systems reside in separate drawings that are linked to the electrical project database file.
Using the electrical project database file, you can create and share the most current circuit information across all drawings in an electrical project. It is required for any drawing that contains circuits.