In my old shop I had a100 amp sub panel. 145 ft from house main panel to shop. The distance from the main panel to the sub panel determines the wire size needed. I used the minimum size per code calculation and the lights used to go dim when someone was welding and the 5 Hp air compressor kicked in. In the new 40 x 120 ft shop my son who is an electrical contractor put in a new feed from the power pole and a 200 amp main panel, 42 circuit and added a 60 amp sub panel next to the lift. seperate feeds to all of the bigger machinery, welder. lathe, mill. chop saw,etc , only 6 general use outlets per circuit breaker. . The wood side got feeds for planer, table saw, turret saw, sawdust colledtor. etc and the lights don't dim.