I have never had to take my I-Techs up all the way. I've also never had a problem running the pair off a single 15 amp circuit with a 20 to 15 amp cheater. The rack these are mounted in has a Furman that will monitor amperage. I've drawn about 7 1/2 amps one time that I saw with my PAIR of I-T 4000 and I-T 8000 in use.
I love my macro-techs, I have 2 5000VZ's, and 2 2402's. However the I-Techs get more use.