i 100% agree.. the s7 is too large for a home miner.. you have to get special outlets if you already dont have 30 amp or 220 outlets. takes 2 high end or one large expensive power supply.
you would be lucky if you break even on cost before the block halfs.. if you dont you might not ever.. its not like the price of btc will double overnight..
bitmain should have made smaller home miners, maybe one of the s7 hash boards. i would have replaced my s3s with one of those.
A normal 20amp 110v circuit will work fine to power one miner. You only need a 220v if you use a 220v PSU most are just using a couple 110v PSU's or a larger 110v PSU.