I am preparing to put in a HWPC. I want to set it up for 100A for future use, possibly for a second HPWC. I also have an outlet in my garage I used for welding (NEMA 6-50). So a sub-panel makes sense. I'd like to run 100A from my main panel to the garage, then to the local outlets and HWPC. I can't imagine ever charging and welding at the same time so I don't think I need overhead on the 100A. A few questions: 1) I'm going to run #3 copper THHN to the sub-panel. However, how do you hook this to the main panel in terms of the neutral? The bus bar in my Square D Homelink won't take anything near a #3 wire. Maybe a #4. So how do you hook up that conductor? 2) At the same time, do I need a #3 neutral if my only 120V loads on the panel would be behind a 20A breaker? The welder and HWPC don't even use a neutral. 3) If I put a 100A breaker in the main, do I need another 100A in the sub panel going to the HWPC? Seems weird to have two 100A breakers in series.