The Neutral (A GrounDED Conductor) carries return current back from the load to the Panels Neutral Buss. The Equipment GroundING Conductor DOES NOT carry any current back from the load, ONLY fault current if a fault exists.
At the main service entrance and only there the Neutral Buss in bonded to the Equipment Ground Buss but still the equipment ground does NOT carry any current ONLY carries current if theres a fault.
PS for the poster and all here: Its IMPOSSIBLE to explain in a paragraph here what can take books to fill and years of engineering practice and experience to fully comprehend SO DONT FEEL A BIT BAD IF YOU DONT UNDERSTAND IT
John T BSEE, JD