National Electrical Installation Standards

Standards as High as Your Own

Wednesday, December 7, 2022


Hello Code Guru, thanks for your daily service to the trade. I just wanted to add a comment to the CQD dated Monday, November 7, 2022:

 “Hello CQD, I am a licensed electrician working with a general contractor on a renovation project in a two-family residence in Massachusetts. Approximately 75% of the entire building will be completely renovated (down to the studs). The GC would like to leave the remaining 25% of the building as is, including the power, lighting, and heating circuits. I would prefer to replace all power. lighting and heating circuits in the entire house since the house is approximately 100 yrs. old and the existing wiring is a combination of very old Romex and BX. Is there a code requirement or state regulation which mandates that the entire building must be brought up to current code for a situation such as this?”

Thanks, Eric Krist


November 7th Answer:

In general, the NEC® provides requirements for new electrical installations, unless a Code Section specifically addresses existing installations. Here are a couple examples of Code Sections that apply to existing installations:

  • 210.12(D) Modifications/Extensions of branch circuits and AFCI protection.
  • 406.4(D)(1)-(7) Receptacle Replacements

Additionally, the answers provided on this platform are based on the NEC®, and do not include information from State or Local codes and/or ordinances. It is always advisable to check with your local AHJ for information on local codes/ordinances in addition to the ones found in the NEC®.  


Eric, glad you are enjoying the CWD, and thank you for the helpful, additional comments on November 7th ‘s question:


In addition to the requirements on existing installations in the NEC®, the building codes by ICC®: i.e., IBC® & IRC® address existing installations. These building codes are adopted by all 50 states.


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.

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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.

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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. 

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