Hello to all. I am running a feeder wire in 2" conduit from my 100 amp breaker in my house panel to my 100 amp garage panel approximately 160' away. I am wondering if #1-#1-#2 Aluminum is sufficient with a #6 Copper ground. Thanks for the help.

The voltage drop will be 6.5 volts across each 120 leg to neutral assuming the load is 80 amps.

Recommended maximum allowance is 3% or 3.6 volts. If the load does not exceed 40 amps, the voltage drop will be 3.2 volts, which will be acceptable.

If there will be large motors, say 5- 10 HP, they may have a problem starting due to the locked rotor amperage combined with any other running load.

Hello to all. I am running a feeder wire in 2" conduit from my 100 amp breaker in my house panel to my 100 amp garage panel approximately 160' away. I am wondering if #1-#1-#2 Aluminum is sufficiant with a #6 Copper ground. Thanks for the help.
Yes # 2 Al or #3 Cu is sufficient. #6 Cu ground is also sufficient. Just remember to remove the bonding screw in the panel in the garage. I suggest burying a ground plate approx. 2' in the ground and tying it to the panel itself

Do not connect the new panel to a grounding electrode as suggested.