I need some clarification/help on wire sizing.If you up your feeder wires for voltage drop you have to up the grounding electrode conductor as well. The code says that it goes by circular mills and thats where i get lost. Can someone clear this up for me or guide me to a previous post. For example if you have a 100 amp service (residential) you would use #4cu if it is 200ft away according to my math and 3% voltage drop it says i need to use a #1cu. i do not know how to size my ground wire though. Any help would be appreciated