I am connecting a 100 amp subpanel from my main panel on my home to be used in my new garage that is 155 feet from the house. The main panel is a 200 amp combo box on the outside of my house that supplies a 200 amp panel inside my house. I have been told that I may use mobile home feeder 2-2-2-4 aluminum wire to do this. I will bury the cable in conduit for the majority of the 155 feet. I believe that I will need one gauge larger and had planned to buy the larger wire before the hardware store told me I could use 2-2-2-4 mhf wire. The cost difference is significant. Is it really OK for the 2-2-2-4 mhf wire. I believe it is only rated for 90 amp at 75 degrees C which is what the panel is rated. Should I go with 2-2-2-4 al or the bigger wire. Thanks

In my area that would be fine since we can use Table 310.15(B)(6) to figure sub-panel feeders. Some areas do not allow the use of this table.

If they do not in your area simply use a 90A breaker.