National Electrical Installation Standards

Standards as High as Your Own


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.

  • ?
    Monday, March 20, 2023


    Dear CQD, I walked a job the other day, and I noticed that someone had installed 3” EMT/ IMC compression couplings on a 5kV rigid conduit run. I’m not incredibly fluent with the install of rigid, is this acceptable? Thanks in advance, Tyler Easton
  • ?
    Friday, March 17, 2023


    Hello CQD, Keep up the great work! Can you please clarify the difference between Service Equipment - Disconnecting means vs Service Equipment - Overcurrent Protection per Article 230. Does it imply that a Separate Disconnect Switch at service is required even though the Service Equipment has a main circuit breaker? thank you. Abhi P


    Hi Abhi, thank you for the kind words and your question.

    Service Equipment - Disconnecting Means: In general, each building or structure connected to an electrical service must be provided with a means to disconnect all ungrounded conductors from those service conductors. This is the function of the Service Disconnect, and covered in Part VI of Article 230.

    Service Equipment – Overcurrent Protection: Each ungrounded service conductor shall be protected from overload. This is typically achieved by using an overcurrent device like a fuse or circuit breaker installed in series with each ungrounded service conductor to provide overload protection. Part VII of Article 230 provides the minimum requirements for Service Overcurrent Protection.

    Even though the Service Disconnecting Means and Service Overcurrent Protection are in two separate Parts of Article 230 it is common to achieve compliance with both Parts, using the same device. For example, a Circuit Breaker that complies with the requirements in Part VI and Part VII of Article 230 could service as both the Service Disconnect and Service Overcurrent Protection. Hope this helps.   

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.