I've got a 20HP RPC box from 'Phase Craft' (see EBay), plus a 20HP GE motor that I bought, refurb'd at a local electrical supply/trading company.

This setup is for a 6.5 kW (9.25 HP) at the spindle, BPort Interact 1 Mk2.

The incoming copper is 6 gauge 4 wire (3 big wires and a smaller Gnd). In this case the Neutral (white) / common is tied to Gnd. The mains amperage supply on my house is 200A. I've got the RPC on 70A SquareD breakers.

I've been running my machine (which has problems not related to the RPC) for around a month now, with no power trouble at all.

The whole setup cost me around $950, including wire / electrical panels / RPC box / motor.

I think I've managed to put this together pretty darn cheap, compared to the stuff thats out there ready-made (not installed) which for 20 HP will cost you around $1400. That's without any wire, panels, conduit, or install.

Get an RPC! It's great! I've measured +/- 4% on between the legs.

Of interest to me, I've got a friend who runs a VFD, which is not a 'static' VFD which he claims does not 1/3rd your available HP. Anyway, good luck to other RPC'ers out there.