Power at the Rack and Judging a Strategy
Rack power has risen from a few kilowatts toward the megawatt designs that NVIDIA and the authors of the Open Compute Project's Mount Diablo specification now describe. At those levels, low-voltage distribution demands so much copper that it crowds out the computers, and the physics points toward higher-voltage direct current. The backing is broad, from ABB and Eaton to Schneider Electric and Vertiv, but codes, protective equipment and field experience lag behind. Faraday's read is that the direction is sound and the timing uncertain, and that the same discipline applies at every scale: separate what has been signed, built and certified from what has only been announced.
Knowledge check
Why does moving rack power distribution from about 54 volts to 800 volts direct current reduce the amount of copper needed?
Show the answer
Power equals voltage times current, so raising the voltage lets the same power flow with much less current. Lower current needs thinner conductors and loses less energy as heat, since conductor losses rise with the square of the current. NVIDIA has said that serving a one-megawatt rack at 54 volts would need up to about 200 kilograms of copper busbar.