I'm going to post this with the statement that actual power consumption involves a lot factors specific to your install. In the end it's a sketch, not a plan to use. If you don't know how to figure all of this out exactly, then hire a pro.

Using 120v power for high draw devices like servers is inefficient, because let's say you have a server that draws 800 Watts.

P = power (Watts) [your 800W server] I = current (Amps) E = voltage (120V supply) P (watts) = I (current) x E (voltage)

800 = I x 120 I = 800/120 I = 6.67 Amps 6.67A is your actual power draw, this is where your electric bill comes from.

Now, your electrician installs 208v 1-phase for small datacenter environments.
800 = I x 208
I = 800/208
I = 3.85 Amps
3.85A is your power draw, you just cheated the electric company out of a bunch of money.

Then you buy a PDU that has 208V outlets, and also 120V outlets because they can be re-strapped in the PDU to limit power. Eaton has a lot of high quality PDUs for good prices, APC/Schneider is good.