I'm upgrading my service to 200A. I already have 2 ground rods (7 ft apart) that are connected with #6 Copper wire. My metal water pipe enters the building on the other side of the house. It is about 80 feet away if I go through the attic and on the outside of the house. I belief I need #4 Copper or #2 Aluminum for this bonding connection. Can I use black #2 Aluminum USE-2 cable or XHHW-2 for this? Given that it is 80 feet, I would prefer to use Aluminum since it is about 1/3 of the price of #4 Copper. What are the requirements of supporting this kind of cable on the outside of my house?