600A Feeder Size

[mjmike]

Right and unless that feeder is supplying a data center it is unlikely that the neutral must be treated as a CCC.

Per 310.B.5.C, for a 4-wire 3-phase Y connected circuit, unless you are powering only resistive loads, everything else would have some form of being nonlinear, IMO.

 

[iwire]

Per 310.B.5.C, for a 4-wire 3-phase Y connected circuit, unless you are powering only resistive loads, everything else would have some form of being nonlinear, IMO.

I am aware of the rule and in my opinion few feeders supply a majority of linear loads.

 

[kwired]

Per 310.B.5.C, for a 4-wire 3-phase Y connected circuit, unless you are powering only resistive loads, everything else would have some form of being nonlinear, IMO.

As mentioned it needs to be a majority of the load.

Also:

Nonlinear Load.
A load where the wave shape of the steady-state current does not follow the wave shape of the applied voltage.

Motors are not resistive loads, but are still linear loads. An inverter or DC supply for a motor may be non linear in regards to the main supply, the driven motor is still linear.