#1 Insulated Wire Insulated copper wire that is 14 gage or thicker (1/14 inch). If wire is stranded, each wire must be 1/14” or thicker. Must have a copper recovery of 70% or more. Most single jacket wire will be classified as #1 wire. Related Projects Plate & Structural Steel All Metals, Steel Aluminum Cans All Metals, Aluminum #1 Copper All Metals, Copper