for high-impedance grounded neutral systems grounding

connection requirements. (b) Grounding Electrode Conductor. A grounding electrode conductor, sized in accordance with Section 250-94 for the derived phase conductors, shall be used to connect the grounded conductor of the derived system to the grounding electrode as specified in (c) below. Except as permitted by Exception No. 4 of Section 250-23(a), this connection shall be made at any point on the separately derived system from the source to the first system disconnecting means or overcurrent device; or it shall be made at the source of a separately derived system that has no disconnecting means or overcurrent devices. Exception No. 1: A grounding electrode conductor shall not be required for a system that supplies a Class 1, Class 2, or Class 3 circuit, and is derived from a transformer rated not more than 1000 volt-amperes, provided the system grounded conductor is bonded to the transformer frame or enclosure by a jumper sized in accordance with Section 250-26, Exception No. 1 for (a) above, and the transformer frame or enclosure is grounded by one of the means specified in Section 250-57. Exception No. 2: As covered in Section 250-27 and Exception No. 5 for