I have a full 100 AMP main, installed a main lug fed by a 60AMP breaker on the main. Between the main and main lug I have NM 6-3 WG copper. I did not use conduit or an offset conduit, but rather 1" DIA. clamps and less than 6" length of NM 6-3 between the main and main lug. The gound wire on the 6-3 is not 6 gauge wiring of course, and I was wondering if there are NEC guidelines on appropriate gauging for the ground. There of course might be local specific codes, but I was first going to see what guidance people on this board might suggest. I can either use the ground in the 6-3 to ground the main lug to the main panel, or optionally add a larger gauge ground dedicated between the main lug and the main. Any suggestions? Also, if I use a larger gauge ground between the two panels, should I bust a new pair of holes claimp too? I doubt it makes sense to go through the 1" dia clamps where the 6-3 NM is. Finally, my neutral of the 6-3 doesn't fit in any of the open screw terminals on the main panel bus, and was wondering if there is a way to appropriately get it to fit. Ideas, in no particular order, include: a. reduce the strands of the 6 gauge neutral (from the 6-3) until it fits into the terminal b. find and buy some sort of adapter (if they exist) to accomodate the larger size c. branch the 6 gauge neutral into two strands and fit each strand into adjacent open terminals on the neutral bus of the main panel. I am guessing that option B is the best, if not most appropriate solution. Your thoughts and suggestions are appreciated.