National Electrical Installation Standards

Standards as High as Your Own

?
Monday, April 26, 2021

Question:

Charlie,
 

I appreciate your forum. My question is if a THHN copper conductor is used for a Grounding Electrode Conductor, does it need to be installed in one of the wiring methods from Chapter 3 as addressed in Section 300.3(A) since THHN is specified in Table 310.104(A)?

Dale Earixson

A

Answer:

Hi Dale,

Thanks for the question. First, the conductor in question is a grounding electrode conductor, which does not carry current in normal operation. Article 310 would not need to be applied. Section 300.3(A) explains that single conductors specified in 310.104(A) shall only be installed where part of a recognized wiring method in Chapter 3. Again this applies to general wiring and wiring methods. Article 250 contains the specific rules related to installation of grounding electrode conductors. See Section 250.64(A) through (A) through (F). According to Section 250.62 the grounding electrode conductor can be solid, stranded, insulated covered or bare.  If a conduit is used to contain a grounding electrode conductor, it is typically for physical protection as may be required by 250.64(B). Section 250.64(B)(2) indicates the types of conduit or tubing that that shall be used for protecting sizes  6 AWG and larger, and Section 250.64(B)(3) indicates the types of conduit or tubing that shall be used for protection of sizes smaller than 6 AWG. Hope this is helpful.

ABOUT CQD: The Code Question of the Day (CQD) is NECA and ELECTRICAL CONTRACTOR Magazine’s flagship National Electrical Code (NEC®) public forum for the industry, sponsored by EATON. The daily distribution of Q&A generates a lively dialogue and shares relative Code-based practical responses.

SUBMIT YOUR CODE QUESTION: Click here to submit a question to for inclusion in an upcoming edition of the Code Question of the Day, or email codequestion@necanet.org

CHARLIE TROUT: Charles M. Trout, better known as Charlie, was a nationally known NEC® expert and author. He served on several NEC® technical committees and is past chairman of CMP-12. In 2006 Charlie was awarded the prestigious Coggeshall Award for outstanding contributions to the electrical contracting industry, codes and standards development, and technical training. Even though Charlie passed away in October of 2015, his work continues in spirit. NECA continues to maintain this question forum for its many subscribers in memory and recognition of all his significant contributions to making the NEC what it is today.

NECA STANDARDS: NECA publishes the National Electrical Installation Standards™ (NEIS™), a series of ANSI-approved performance and quality standards for electrical construction. NEIS can be purchased in the NECA Store in three formats: a printed or PDF download of a standard or, as an annual subscription service.

NECA SAFETY PRODUCTS & PUBLICATIONS: NECA produces electrical safety publications and products for the industry including jobsite safety guides, handbooks and resource kits. View a full listing of available resources and products »

IMPORTANT NOTICE: Unless the question requests a response based on a specific edition, all answers are based on the latest edition of NFPA 70® National Electrical Code®.

This correspondence is not a formal interpretation of the NEC® and any responses expressed to the questions are opinions and do not necessarily represent the official position of NECA, NFPA, the NEC Correlating Committee any Code-making panel or other electrical technical committee. In addition, this correspondence is neither intended, nor should it be relied upon, to provide professional consultation or services. 

UPDATE YOUR SUBSCRIPTION PREFERENCES: Subscribe or Unsubscribe from this list.