Neutral Calculation

[Butler]

If I install 3, 20 amp 1 phase branch circuits (12 AWG), can I use 1 common neutral conductor (12 AWG)?

 

[roger]

It depends on the supply system.

Roger

 

[Butler]

Supply is from a 120/240 volt panel.

 

[kingpb]

Then according to your supply voltage of 120/240V you cannot. You need at least two, you should refer to NFPA 70, Article 210.

 

[roger]

The panel label is not really relevant, you need to know what the supply system is. Is it single phase, three phase, four wire wye, four wire delta, etc...?

Roger

 

[Butler]

The system is a 120/240 volt, 3 phase, 4 wire wye fed panel.

 

[don_resqcapt19]

Butler,

The system is a 120/240 volt, 3 phase, 4 wire wye

There is no such system. If it is a a wye, the voltage is 208, not 240. If you have 240, then it would be a 4 wire high leg delta.
Don

 

[Butler]

You are correct it is 208. Can you help me with the neutral question?

 

[LarryFine]

You are correct it is 208. Can you help me with the neutral question?

Now we can.

Yes, as long as no two line conductors originate from the same phase.

Keep in mind that was a very general question, as is the answer.

 

[Butler]

Thank all of you!

 

[kingpb]

You are correct it is 208. Can you help me with the neutral question?

Then that would be a 208Y/120V, system :grin: