According to this
chart I have at least a 5 gauge wire because it is between 3/16" and 1/4" for sure and by my simple conversion factor of the diameter of the wire(.25 or 3/16)times the inches to centimeter conversion(2.54) times centimeter to mm conversion(10) that gives me 6.35mm for 1.4" and 4.7625 for 3/16". Then, that means I have somewhere between a 5 and 2 gauge wire. Even accounting for error it leaves plenty of room for 6 and 8 gauge which are supposed to be sufficient.
