I am installing a point of use Chronomite SR-20L/240 HTR 240-Volt 20-Amp SR Series Instant-Flow Low Flow Tankless Water Heater. https://www.amazon.com/Chronomite-SR-20L-240-HTR-Instant-Flow/dp/B001B1KGUQ
I have called the company and they tell me that I need two pole 240v, 20 or 30 amp breaker. They said that it is wired with two hot and one ground 10 gauge wire. This is a new install for a bathroom I am building in my garage. I am having a problems finding romex type wire that has two black (hot) wires or a black and a red (hot) wire and a ground wire. They told me if I used 10/3 wire with a ground to cap the neutral wire. I need about 35 feet of wire.
My concern is with my inspection and having the proper wiring colors for my hot wires. If I get 10/2 with a ground, I will have a hot,neutral and a ground, but the neutral will be white. Please advise what the name of the particular wiring I need is called.... that has a black,red and a ground wire. Thanks!