Electrical - 2-0 Copper
2/0-AWG Stranded Black Copper THHN Wire
http://www.lowes.com/pd_72617-295-20506245_0__?productId=50101590 $2.55. Then 6% when buy 500 feet ($2.40). Then 5% with Lowes card ($2.28). Then 10% HomeDepot match ($2.05).
The distance through the conduit from the main panel to the sub-panels in the house is about 210 feet. I need 8 wires.
May be best to use Aluminum, eg http://www.lowes.com/ProductDisplay?partNumber=10155-295-13107808&langId=-1&storeId=10151&productId=3127469&catalogId=10051&cmRelshp=req&rel=nofollow&cId=PDIO1
Need to check it is ok to used jacketed cable in conduit.
Need to ask local electrical inspector what wire gauge they require.