As you probably know, THHN is a good general purpose building wire - stranded bare copper with PVC insulation and Nylon jacket designed for applications utilizing less than 600 volts. Ten-gauge is pretty hefty, but it will certainly work fine as a dedicated line for your system. Make darn sure you run it all the way back to the fuse box though, as the rest of your house is likely wired with 14 or 12. A dedicated 12G line would suffice just fine, and 12G is easier to work with than 10G. I used 10G for a dedicated line in a previous home and today I utilize a dedicated line with 12G - darned if I can tell any differences.
