Ryan,

I'm just being letter of the law snotty here [Linked Image] I agree that my 'silly' example is something that _should_ violate something in 250.4(A)...
but:
250.4(A)(1) Not relevant to the branch circuit.
250.4(A)(2)-(4) simply say that all of the conductive materials need to be connected to the EGC, and that the impedance must be low enough to limit the voltage of these matierials. 2000 feet of #12 has a resistance of 3 ohms; which is certainly better than the 25 ohms mandated for grounding electrodes (when you only have one, when you test, la la la). The inductance of 2000 feet of wire needs to be considered for things like lightning imposed voltage...but this will be essentially unchanged when the conductor gets larger. The voltage imposed by a bolted fault would be 60V, which sounds limited to me.
250.4(A)(5) says that the ground fault current path must be able to safely carry the ground fault current. #12 can certainly carry the expected ground fault current (20A)

There is no definition of 'Effective Ground-Fault Current Path'. If an 'Effective Ground Fault Current Path' means 'must trip a breaker', then 250.4 implicitly limits voltage drop in _both_ the supply and egc. Consider a branch circuit with #12 hot and #12 neutral and #0 EGC. You still won't have a ground fault current path that would reliably trip the breaker.

-Jon