I am planning to have a HPWC installed when it comes in (est. to take 1-2 months) and wanted to do a couple things myself before it arrives to ensure quicker and cheaper installation. Specifically, I wanted to run the wiring myself from the Circuit breaker to the location where the HPWC will eventually be installed. The box with the breaker is located inside of the garage and I want to install the HPWC about 5-10 feet away from this box in the same garage. The wiring will need to exit from the top of the circuit box (which is between two studs) and run upwards into the attic above. From there, the wiring will need to run along the subfloor to the attic area located directly above the location marked for the HPWC. The wiring will then come down between the studs and behind the garage wall until it reaches the specific spot where the HPWC will be installed. The question that I had was regarding the requirements for running this wire inside the walls and inside the attic. I know that I will need to use two 3-gauge THHN wires for the two live wires and am planning to use 8-gauge THHN (Green) for the grounding wire. I was planning to run these inside of 1" conduit inside of the walls, as I do not want the conduit to run on the surface of the walls, and eventually I want the conduit to run into the back opening of the HPWC so that it will remain entirely concealed. My question was, what would be the best (or easiest) type of conduit to use for this installation since it will require a couple 90 degree or so bends? Can i use flexible nonmetallic conduit, i.e. ENT, like the blue smurf cable that is sold at Home Depot by Carlon? [Link: Carlon 1 in. x 25 ft. Electrical Non-Metallic Flex Tubing-12008-025 at The Home Depot ] The reason I wanted to use this conduit was because it was easily available at Home Depot and is flexible so I could run it without worrying about using fittings at the bend and corner areas. If this tubing will not work for this specific purpose, then what tubing or conduit should i choose to use (preferably conduit that is available at local hardware store like Home Depot)? I was able to find rigid 1" conduit in both EMT and PVC on the Home Depot website and both are available at my local Home Depot in Texas, but thought that flexible conduit would be easier to run in this case. I could not find any other 1" flexible conduit (either metallic or nonmetallic), other than the Carlon Blue flex tube, on the Home Depot site that showed it was available at a store location near to me, as the ones I found on their site either were online only or were not available at any home depot in the Dallas, TX metroplex (unless the site is incorrect regarding the in-store availability of certain products). Perhaps I am also searching incorrectly and thus not able to find the correct product that is readily available at all stores. Nevertheless, any recommendations or advice on this front would be much appreciated. My second question was: what would be the easiest way to fasten the conduit along the wood studs as it runs up into the attic from the circuit breaker panel and runs down from the attic, behind the garage walls, toward the location marked for the HPWC (Is there any way to possibly secure the conduit along the wood stud behind the walls without removing the drywall in these areas)? Lastly, besides having to securely fasten the conduit at locations of every 3 feet, are there any other requirements for me to keep in mind as I perform this installation? Thank you in advance for any assistance with these issues. I appreciate all of the help that anyone can provide.