Ground Wire

In response to Avguygeorge's suggestion, I first used 12 gauge unstranded and didn't notice much change, then went to 10 gauge unstranded and got a BIG change. I think most would advise no smaller than 10 gauge, though of course I could be wrong about this. Whether stranded or not, again I'd seek expert opinion. I was told to use unstranded, and it certainly worked for me. I also use an 8' copper-plated brass rod all-but-completely buried in the ground.

Sorry, I didn't read carefully enough. I was installing a third wire ground for my stereo system dedicated line, not regrounding a main panel. Still, similar considerations may apply.

Usr insulated back to the pannel to avoid ground loops.

#8 solid uninsulated copper is frequently found in this application

What benifit would a non insulated wire have over an insulated wire? Wouldnt the insulation help block noise?