[Discuss] Server Room Power

[Matt at MattKowalski.com (Matthew Kowalski)]

Does anyone have any experience with running server equipment (Dell Power
Edges, HP Proliant DL G7s & HP c7000 Enclosures) at 208 VAC instead of 120
VAC?  Right now we're running 20 Amp circuits at 120 VAC but I've been
reading some on the web about better efficiency at 208V along with
additional power available.  The main issue we're having is getting enough
power to the racks to run the power dense equipment.

Given one form of Ohm's as Power (Watts) = Current (Amps) x Voltage (Volts):

The max power out of a single phase 20A 120VAC circuit is 2400 Watts.
The max power out of a single phase 20A 208VAC circuit is 4160 Watts.

Since only 80% of the power should be utilized the max power would be
reduced to 1920 Watts and 3328 Watts respectively.

Am I missing something?  We've got a network power unit that can output
various VAC voltages and up to 3 phases so this is really more of a
distribution to the rack question.  I'm thinking all I need is an
electrician to add additional circuits, am I right?

Thanks for any input!