Power Supply Sizing Question Hello, I am compelled to start this topic with stating a fact that will soon become painfully obvious in the near future anyway. I am a total freaking noob when it comes to mining. I do however have an extremely good friend that writes software, who volunteered to write whatever code is required. Which leaves the hardware to me, a very scary thought, to say the least. I'm a master electrician, have owned and operated my own construction company for decades. (I am still in business) Which probably means I know just enough to burn my freaking house down with the rig I'm building, but at least my insurance is paid. I picked up a pallet of servers at auction, and am going to start out with two HP Prologic DL 370 G6 servers. They each have 10 slots I can use risers on, and I have 18 cards to start with, but am buying as I find them for good prices on used cards. I picked up a used 96U server rack, full of rails, with intake and exhaust fans. I'm going to weld up my own external 10 card racks out of aluminum for good common ground, and mount on an insulating material base like polystyrene or polyurethane sheets 3/8" thick. I am waiting for the 1st 2000 watt 94% efficiency 240V power supply, which I will use for the external card racks. Being that I have engineered and built everything from single family homes, to mixed use apartment complexes, to large commercial pot grows,(I'm in Washington State), and lots of office buildings and restaurants, I am pretty stuck on NEC and IEEE guidelines for electrical design. I calculated each card will consume 75 Watts of power. Since each server will handle 10 cards, that makes 750 watts. Then I add a 20% overload factor, in this case it is 200 watts. A total of 900 per every 10 cards. That tells me I can go 20 cards, for a total of 1800 watts, to safely run off one power supply, with an excess of 200 watts, which will increase the safety factor. I believe the power supplies are either one or two 12 volt only rails, and figured as long as I had an even number of taps, I would maintain a balanced load. Have I missed something? Thanks in advance.