AutoCAD Electrical toolset supports a user table in the project database. You can add your own application data to any AutoCAD Electrical toolset block insert (components, footprints, wire numbers, terminals, wire jump arrows). A copy of this information is extracted and maintained in a USER table in the project database. This allows you to do queries on the project database file (in Microsoft Access format) and access all of this user information carried on all entities project-wide. This data is stored on the entities as invisible extended entity data. You are free to use this data in any way you see fit.
Examples: storing explicit wire sequencing information, cable or wire lengths, routing information, storing special parts information, descriptions, or MRP data, storing engineering notes, setup, or maintenance information, and so on.
Each application data record that you add to an entity can be up to 255 characters long. A single AutoCAD Electrical toolset entity can carry several hundred of these records. Each record is tracked on the entity by entity handle plus a three digit record number beginning at "000". This same information is automatically maintained, project-wide, by AutoCAD Electrical toolset in the user table of the project's database file.