Hi, I've tried some searching but have not gotten enough information. I'm researching on how to install an hpwc at home. I do have the 72A charge option and want to take advantage of it. My main panel is 200A and is located on one side of the house, and about 75+ feet away towards the other side is the garage. Power is split, 100A for this side of the house and the other half goes through a sub panel for remaining 100A for the AC units and dryer hookup. The garage is closest to the AC units. In order to add this new 100A line: Will I need to upgrade my main panel to a 400A box? Approximate cost? And do I need a city permit? Also, any idea on how to run the 100A cable to the hpwc? Dig trench around house or run some pipe to the attic and then drop down to the garage? I am approximating 75 feet for this cable run. I have not called for quotes yet, just wanted to do some research first to get a ballpark cost. Any feedback appreciated.