I will be doing an addition to our home over the next year. One of the first steps of this is upgrading our existing service to 400 amp and then pulling a 200 amp subpanel that will be mounted on the back of the new attached garage we are building approx 100 feet from the main panel (i can mount interior or exterior). The 200amp sub panel will feed a 5 ton AC unit and standard outlets and lighting in a 24x30 garage. I intend to later pull a 100 amp feed off the 200 amp panel for a later planned shop. Heres my question - I intend to run the feed through the entire length of the attic of my home and into the new attached garage to the sub panel. What wire size do I need for 200 amps at 100ft and is it required to run in conduit through the attic? I am in Arizona and it gets hot up there too. Thanks for any and all help!!!