Section 250.64(B) provides a list of requirements for securing and protecting a grounding electrode conductor (GEC). The protection requirements are applied based on the size of the GEC and whether the GEC is exposed to physical damage.

For GEC’s in contact with the earth, Section 250.64(B)(4) makes it clear that the burial depth Table 300.5 does not apply to GEC’s. If subject to physical damage, a GEC in contact with the earth must be protected or buried but the NEC^® does not specify how deep.

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) Securing and Protection Against Physical Damage.

Where exposed, a grounding electrode conductor or its enclosure shall be securely fastened to the surface on which it is carried. Grounding electrode conductors shall be permitted to be installed on or through framing members.

(1) Not Exposed to Physical Damage. A 6 AWG or larger copper or aluminum grounding electrode conductor not exposed to physical damage shall be permitted to be run along the surface of the building construction without metal covering or protection.

(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.

(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.

(4) In Contact with the Earth. Grounding electrode conductors and grounding electrode bonding jumpers in contact with the earth shall not be required to comply with 300.5, but shall be buried or otherwise protected if subject to physical damage.