Lots of good discussion here... Now, as a kid I grew up on a farm and the barns had lightning rods that were attached to stranded copper about #3 to 1/0 in size IFIRC. Years later, I did splicing and all the poles were grounded with #10 solid (stuff still got fried in the houses); but never saw a melted ground. Yes, I have seen wires that have been subjected to Arc Flash and what happens when they explode / burn. Not a pretty sight.