I'm in the process of converting my system for electric brewing, I put in a 4 wire 240VAC dryer outlet like is described at the electric brewery web
site, excellent resource. This way you can run a 5500W element and boil 10 gallon batches easily.
I used a 120VAC HLT in the past, but even with preheating the water to 140ºF out of my thankless water heater getting the water up to strike temp and Sparge temp was a long process. 240VAC is a good way to go if you can.