# 1 copper is thick copper wire such as clean Romex any thick copper wire that is clean of insulation.
#2 copper is mostly copper pipe, and smaller strands of copper wire such as in lamp cords etc once the insulation has been removed.
So according to my scrap yard I go to #1 copper is copper wire that is 1/8" or thicker and 14 gauge or larger size copper wire.
#2 scrap copper is any copper wire that is less than 1/8" in thickness or 15 gauge or thinner and number 2 copper can be bar stock copper.