I'm studying Article 215 (Feeders). The "Text book" makes the statement that that the "Grounded" conductor of a FEEDER can be sized no smaller than #4 AWG and points to T. 250.122 in the 2008 NEC to support of this statement.

Problem, T 250.122 is addressing "Grounding Conductors", not "Grounded".

I have reviewed Articles 250, T 250.122, 310.15 (4) and T 310.15 and I cannot find a statement limiting the size of the Grounded Conductor on a feeder to no smaller than 4 AWG.

Is there such a statement and if so, where is it supported in the Code?

Please post the exact text from Article 215 you are referring to.

The term I am referring to is not in the NEC, it is in the textbook and I cannot find verification for the statement in the NEC.


..... but the Neutral conductor is not permitted to be smaller than 4 AWG as listed in table 250.122 based on a 250A overcurrent device."

Beats me what your test book is talking about.

Sounds like they are trying to explain an example of a 250 amp circuit, which according to Table 250.122 would need a min of #4 EGC,

Then based on Section 215.2 states that the grounded conductor shall not be smaller that the EGC listed in Table 250.122.

Now why there would be a grounded conductor for a 250 amp feeder I will never know.

TK,

Thanks. I have two problems with their statement.

1) I cannot find verification of the text in the code book.

2) I do not understand why you would use a table describing "Grounding" conductors to size a Grounded conductor. It makes no sense to me.

When all else fails, I guess I can ask the teacher on Tuesday.