So, I know this isn't entirely an Engineering question, but I am an EE and I wanted to get a few opinions on my planned project. I have had a central vacuum in the past three homes I have owned. I have always installed the unit and all plumbing myself, but the units are still $500-$1000 just for the power unit in the garage. The units are EXTREMELY simple, essentially a metal drum (like a cylindrical trashcan) with an off-the-shelf vacuum motor attached to it, typically made by Ammetek Lamb. The motors run anywhere from $50 for a chinese knock-off, to $85-$200 for genuine Ammetek. One of my units that I owned was a dual-motor 240V unit, each motor was 240V. I am looking at building my own unit, utilizing a stainless steel cylindrical trashcan (parallel sides), and buying the Gore fabric filter intended as a replacement for the off the shelf units. All said and done, I think I can build a pretty good dual-motor unit for about $300 or less. Here is my question that I'd appreciate any feedback on... Would there be an issue running 120V motors but running a single 12/3 w/ground Romex line from a 20A 240V dual-pole CB to a 240V outlet (looks similar to a regular outlet, but with the blades sideways), then inside the unit I would run each motor off a single leg. The alternative is a single pole 30A breaker in the panel and run a 10/2 w/ground romex and run the motors in parallel, but I could still put a 10-15A breaker on the unit for each motor (many of the central vac units have built-in CB(s) to help reduce risk of fire or damaging motor). The other thing I'd like an opinion on is regarding soft-start. The motors are universal type motors, like a circular saw or router. Some of the more modern/$$$ units have a circuit that soft-starts the motor to help motor life and start-up current. Second to building a soft-start circuit using a triac or something, I was thinking about just using a time delay relay that will have the motors in series off one leg, then one motor switch to the other leg and each getting full 120V after 2 seconds. Any thoughts/opinions would be appreciated!