How do I select the correct weld cable size for the XMT 304?

Cable size depends on the total cable length in the weld circuit and the duty cycle being used. For example, at 100 ft (30 m) or less at 10–100% duty cycle, a 4 AWG cable is recommended for lower amperages, scaling up to larger sizes for longer runs. Weld cable size is based on either a 4-volt or less drop or a current density of at least 300 circular mils per ampere. (Page 16)