?
Friday, October 2, 1998
Question:
The service entrance grounded conductor's minimum size has what relationship with the grounding electrode conductor?
A
Answer:
The service entrance grounded conductor has to be as large as the grounding electrode conductor. Section 230-23(c) says that the grounded conductor shall not be less than the minimum size as required by Section 250-23(b). Section 250-23(b) says this conductor shall be routed with the phase conductors and shall not be smaller than the required grounding electrode conductor specified in Table 250-94, and, in addition, for service-entrance phase conductors larger than 1100 kcmil copper or 1750 kcmil aluminum, the grounded conductor shall not be smaller than 12 1/2 percent of the area of the largest service-entrance phase conductor.
So, even if you don't need it, ya gotta take the grounded conductor (if it is available). And even with a very small calculated load, the grounded conductor has to be as large as the grounding electrode conductor. In addition to all that, if the phase conductors are bigger because of anticipated voltage drop, the grounded conductor has to be upsized as well.