314.17 Conductors Entering Conduit Boxes or Fittings sends me to 314.17(D) Conductors 4 AWG and Larger (I use #4 bare) which sends me to 300.4(F) Insulated Fittings which states "ungrounded conductors" so it's exempt there...
250.64 Grounding Electrode Conductor Installation doesn't seem to help much either...
Aye yi yi... (or however you spell that!)
-Virgil Residential/Commercial Inspector 5 Star Inspections Member IAEI