How's to ground for the dedicated line?

Grounding is a very tricky venture. There are many ways to ground with some not working very well. A copper 10 ft. ground rod works well if you don't have sandy dry soil. If the soil is dense and moist, it will work well. Rebar into a cement foundation will work well if your house has that type of set-up. Many are already setup that way and little is needed to add to that. Making sure connections are good and clean is paramount. Try to have your dedicated line run underground in electrical pipe. Our local code requires an 18" depth. The previous advice is all good and I would add that most electricians are skeptical of a dedicated line making any difference and they may want to run stranded wire because it is easier to pull, but stick to solid core 12 gauge and preferably 10 gauge, but this will not be popular with the electrician. If you have ever worked with it, you will know why. I installed my two dedicated lines and they are very quiet. I used 12 gauge because my run is only 25ft. I also used hospital grade ac outlets as I am sure you are using. Buy them for the electrician because they will probably use what is in the truck and that could be a cheesy model which uses the clip type of ac outlet which is just a fire hazard. They cost about .60 cents and not worth that. Spend the 15.00 and get a good one. My dad is an electrician so that is how I could install mine. You need a contractor to be legal. If you do it yourself and have an electrical fire, homeowners insurance may not be real helpful if they know you did the work. Happy listening, Jallen