When a grounding electrode conductor is exposed to physical damage (regardless of size), or even if not exposed to physical damage but it is smaller than 6 AWG, grounding electrode conductors require protection.
NEC 250.64(B) provides the rules on protecting a grounding electrode conductor and the items that are permitted to be used to provide that protection which includes rigid metal conduit (RMC), intermediate metal conduit (IMC), Schedule 80 rigid polyvinyl chloride conduit (PVC), reinforced thermosetting resin conduit Type XW (RTRC-XW), electrical metallic tubing (EMT), or cable armor.
A common code violation is when Schedule 40 PVC is used to enclose a grounding electrode conductor that is exposed to physical damage. PVC conduit is permitted to be used to protect a grounding electrode conductor from physical damage but only if schedule 80. This aligns with UL product category DZYR for rigid nonmetallic PVC conduit which states:
Schedule 40 conduit is also suitable for aboveground use indoors or outdoors exposed to sunlight and weather where not subject to physical damage. The marking "Schedule 80 PVC" identifies conduit suitable for use where exposed to physical damage and for installation on poles in accordance with the NEC.
Below is a preview of Article 250. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2020 NEC® edition of NFPA 70.
2020 Code Language:
250.64(B)(2) Exposed to Physical Damage. A 6 AWG or larger copper or aluminum grounding electrode conductor exposed to physical damage shall be protected in rigid metal conduit (RMC), intermediate metal conduit (IMC), Schedule 80 rigid polyvinyl chloride conduit (PVC), reinforced thermosetting resin conduit Type XW (RTRC-XW), electrical metallic tubing (EMT), or cable armor.
250.64(B)(3) Smaller Than 6 AWG. Grounding electrode conductors smaller than 6 AWG shall be protected in RMC, IMC, Schedule 80 PVC, RTRC-XW, EMT, or cable armor.
Refer to the image of the grounding electrode conductors in the PVC raceways:
Which of the following is true?
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