200 % neutral PDU

[rewatson]

We have a 200% Neutral Power Distribution Units in a "Data Center". Do we need a 200% Neutral to the 120Volt-20amps wiring to computers receptacles.

 

[peebee]

Typically an individual circuit with individual neutral is run to each rack. That would really provide a 300% neutral.

If you're using shared (triplexed or networked) common neutrals, you should consider 200% neutrals depending on the circuit loading, expected harmonics, wire size, etc.

 

[busbar]

As alluded to by peebee, keep in mind that a set of three 2-wire circuits {from a wye source} in one raceway will constitute six current-carrying conductors, requiring NEC310 derating.

That would typically mandate 10AWG conductors for a set of 20-amp branch circuits.

 

[jbartos]

Suggestion: Please, would you provide more information regarding the power distribution unit, whether or not it is three phase 4-wire or single phase 3-wire. Normally, if your run two conductors and ground to each receptacle, not considering a split duplex receptacle, the neutral to this receptacle is supposed to be 100% only, not 200% or more. The larger neutrals come into picture for three-phase panels or on the single phase three wire systems (240/120V single phase, 3-wire panel). If you post the panel nameplate data, then it will be easier to provide the correct answer.

 

[RajT]

From what you say, the circuit to each recepticle is a single phase circuit at 120V.
The cable from the panel board to each of these recepticle should have a normal size (ie both wires of the same xection area)neutral and not 200% neutral.

 

[jbartos]

Suggestion to the previous posting. Yes, your statement is correct. Both conductors to the receptacles, phase (hot) and neutral should be of the same AWG or similar gauge. Of course, there is no restriction on higher cross-sectional area of conductors; however, it is not required, easily available off the shelf, costs more, and not justified.