OESC 690.47 Grounding Electrode System.

In Oregon, where a grounding electrode conductor is required by 690.47(A), (B), (C), or (D), it shall not be smaller than 6 AWG copper or 4 AWG aluminum.
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In Oregon, where a grounding electrode conductor is required by 690.47(A), (B), (C), or (D), it shall not be smaller than 6 AWG copper or 4 AWG aluminum.

The grounding electrode system requirements for a PV system seem to change with each new code cycle. As well, certain rules back in Article 250 may permit the grounding electrode conductor for the PV system to be as small as 14 AWG copper.

In Oregon, the minimum size of the grounding electrode conductor for a PV system is simple. See the amended OESC code language below:

690.47(B) Grounding Electrodes and Grounding Electrode Conductors.

Additional grounding electrodes shall be permitted to be installed in accordance with 250.52 and 250.54. Grounding shall be permitted to be connected directly to the PV module frame(s) or support structure. A grounding electrode conductor shall be sized according to 250.66, and shall not be smaller than 6 AWG copper or 4 AWG aluminum. A support structure for a ground-mounted PV array shall be permitted to be considered a grounding electrode if it meets the requirements of 250.52. PV arrays mounted to buildings shall be permitted to use the metal structural frame of the building if the requirements of 250.68(C)(2) are met.

Oregon amendments to the 2023 NEC® are located in “Table 1-E” of the Oregon Electrical Specialty Code (OESC) which can be seen using the following link or the OESC PDF file located near the bottom of the screen: 2023 OESC

  Click here to view the OESC  

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OESC 690.47 Grounding Electrode System.

Below is a Real Question from our Electrical Continuing Education Courses for Electrical License Renewal:

Which of the following is required when installing a grounding electrode system for a photovoltaic system installation?

A: If a grounding electrode conductor is required by 690.47(A), (B)(C) and (D), it shall not be smaller than 6 AWG copper or 4 AWG aluminum.
B: Grounding electrode conductors must be insulated and be listed type PV wire.
C: Any grounding electrode conductor required by 690.47 must be sized based on NEC Table 250.66.
D: The grounding electrode conductor must always be installed in a raceway.
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