ECN Forum Forums Code Related Discussion NEC & other Code issues Conduit ?

I just finished building a barn that will have a 100a sub panel, I put in a 2" pvc to run 4 THHN cables #3?. Can I put 4 #1/0 copper in a 2" instead? I found a great deal on 1/0 and thought that if I ever put in a bigger panel I would be set. Thanks for any help.