If you are using Revit for electrical design, sometimes you need a piece of electrical equipment to have more than one feed but carry the same load. A common situation for this is an Automatic Transfer Switch (ATS) where it is fed through both the primary electrical system and an emergency backup system powered by a generator. Downstream panels served by the ATS will receive power from both the primary electrical system and the emergency power system.
This is possible through having 2 electrical connectors on the electrical equipment family. Each connector can then be connected to the appropriate electrical system and show the same load.