For those that say a 14 or 16ga will do, They might.  An issue, as discussed on page 1 is loss.  Volts below 105 are likely to increase heat in the appliances (A/C, MW) and cause heat damage.  That damage may not be immediately visible and is accumulative.  I have seen some say that their appliances worked fine.  That may appear so until they die years before they should.  I always suggest a plugin, digital voltmeter, such as a Kill-A-Watt, to monitor your available electricity.  For a few bucks more you can move up from 14gs to 10ga.  The suggestion to use the 30amp cable as primary is a good one.