quote:6/3 SO/SOO cable has a rating of 55amps as opposed to 60amps in regular cable.
By "standard cable", do you mean romex or THHN building wire? Both of those are not nearly as flexible as SO/SOO/SOW cord. Romex and THHN typically have 7 or 19 strands and #6 cord has ~100 strands.
Basically, #6 cu wire is #6 cu wire. You can't change its properties to increase the ampacity (ampere carrying capacity). Increasing the current in a wire increases the wire's temperature, which, in turn, increases voltage drop.
Type SO/SOO/SOOW cord/cable typically has an insulation temperature rating of 30*C (86*F). THHN building wire will carry 55 amps at 60*C (140*F), 65 amps at 75*C (167*F), and 75 amps at 95*C (194*F). 75 amps through #6 wire just about doubles the voltage and almost boils water.
As Larryw suggested, check out renting what you need.
John