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Monday, December 13, 2021
Question:
Greetings,
I and a colleague respectfully disagree with each other, regarding the installation of ground rings. The disagreement comes when we interpret Sec. 250.52(A)(4) of the 2020 NEC. In my opinion, the phrase, “encircling the building,” is modified by the requirement that the minimum size No. 2 AWG bare copper conductor is only required to be 20 feet in length, whether or not that 20 feet is sufficient to encircle the entire building. In my colleague’s opinion, the minimum size No. 2 AWG bare copper conductor must encircle the entire building and, in no case, be shorter than 20 feet in length. Please give us your opinion on this matter.
Respectfully,
Joseph Kraft
A
Answer:
Hello Joe,
The short answer is ground rings must encircle the building or structure where they are installed. The minimum length for a ground ring is 20 feet. Section 250.52(A)(4) reads as follows: Ground Ring. A ground ring encircling the building or structure, in direct contact with the earth, consisting of at least 20 ft. of bare copper conductor not smaller than 2 AWG. Section 250.53(F) requires that the ground ring shall be installed not less than 30 in. below the surface of the earth. Hope this is helpful.