50% Neutral

[maghazadeh]

Hi All,
Is 50% neutral allowed for a feeder to a 208/120V sub-panel, where 90-95% of the loads are HVAC 3 phase load with no need for neutral?
This feeder will be a 400A/3p.

 

[kwired]

Hi All,
Is 50% neutral allowed for a feeder to a 208/120V sub-panel, where 90-95% of the loads are HVAC 3 phase load with no need for neutral?
This feeder will be a 400A/3p.

Just got done posting this in another thread.

Neutral does not even need to be run if there is no load utilizing it. If neutral is needed - it needs to be sized for maximum current it will carry, but be no smaller than the required equipment grounding conductor for the same circuit which is according to table 250.122. So if you have a 400 amp overcurrent device the neutral can not be smaller than 3AWG copper.

Read 215.2(A)(1)

 

[maghazadeh]

Kwired,

Thank you for your quick reply.

 

[kwired]

Kwired,

Thank you for your quick reply.

Was just right timing. I had just answered a similar type of question and even quoted same code section in another thread, then I read your thread and it occured to me - I think I know the answer.