National Electrical Installation Standards

Standards as High as Your Own

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, William Ekstrom


William, thank you for your question. 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®.  

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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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