National Electrical Installation Standards

Standards as High as Your Own

Thursday, September 15, 2022


Top of The Morning Charlie, thank you for the daily read and your daily work in educating us further your input is always appreciated. When installing or replacing the screws for a load center cover, if the screws become stripped out in older existing installations when doing service work or have been lost, is it a code violation to install a sheet metal screw or a thread forming screw to get the cover installed? The instructions that I have read (SQ D QO) say to install the cover with the screws provided. Most load centers and covers are entirely painted surfaces but it appears the screws that come with the cover might have some bonding capabilities that a substituted screw might not have. 110.3(B) requires following manufacturer's instructions, 250.4(B)(4) would require bonding of the cover. 250.8(A)(5)&(6) mention the screw thread requirements, 250.12 discusses clean surfaces.

Kindest Regards,

Brian Frion



Brian, thanks for the question, you are definitely on the right track with your thoughts here. Section 110.2 of the 2017 NEC requires electrical equipment to be approved. The approval of said equipment is the responsibility of the AHJ. The AHJ is given guidance in judging the acceptability of electrical equipment in Sections 110.3(A)-(C). Often the AHJ will base their approval of equipment on the equipment being listed. When a Nationally Recognized Testing Lab lists a manufacturer's product, the installation instructions are part of that listing. The listing of that product essentially becomes contingent on that product being installed in accordance with installation instructions. If the installation instructions require the use of the provided screws for attaching the cover, then those are the screws that must be used to maintain the products listing. 

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

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.