National Electrical Installation Standards

Standards as High as Your Own

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  • March 10, 2020

    Charlie, Thank you for your service. I enjoy reading your emails every morning. I gave a contractor that is arguing that 210.70 does not require a switch located at or near an exterior door. He says as long as there is lighting outside controlled by a switch anywhere in the house that satisfies the code. I contend that every door leading to the outside must have a switch reasonably close to that door. What is your read on this code? Thanks, Robert Harris
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  • March 9, 2020

    Comment on Code Question and Response for February 3, 2020: Good Morning, You may be mistaken with part of your answer for the concrete encased electrode question. For 4/0 cu or 250KCMIL al the minimum size grounding electrode conductor is # 4 cu or # 2 al (T250.66). Your final answer # 4 cu is correct (250.66B). Thanks for the great service guys. Look forward to it every day. Nom Feck
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  • March 6, 2020

    Comment on Question and Response for February , 2020: Good Morning. This is almost always my first read of the day. Keep up the good work. Regarding the answer for the CQD for February 4. I think it’s important to note that although Section 440.14 says the disconnecting means must be in sight there is one more step in this process. It should be noted that in Article 100 “within sight” and all other variations of it are defined. The equipment must be visible and not more than 15 meters (50 Ft.) distant. Stan
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  • March 5, 2020

    Greetings Code Question of the Day, I heard that the new NEC is requiring whole-house surge protection installed at the service. What section requires this? Thanks for any assistance provided. I enjoy reading the CQD each day. Ralph Cummings
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  • March 4, 2020

    Comment on Question and Response from CQD February 6, 2020: Charlie, While the field electrician cannot install a sheet metal screw for the grounding connection to a luminaire, the listed fixture often has a sheet metal screw for the connection of the EGC by the electrician. That screw is part of the listed equipment and is permitted to be used for the purpose. Don Ganiere
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  • March 3, 2020

    Comments from Question and Responses on 02-07-2020: Re : "Is a duplex receptacle one or two receptacles." As with many Code questions, checking the definitions of Article 100 may be of great assistance. Being on the same yoke does not change the fact that you could connect two attachment plugs to the duplex receptacle. A duplex is by definition a "Multiple Receptacle" device - two receptacles on one yoke. However, do not allow this to become a confusion regarding load calculations. Refer to Article 220, and particularly 220.14. Pay special attention to 220.14(A), and (in general reference to your question) 220.14(I). As a general rule, the duplex (or triplex) on one yoke is still considered a 180 VA load. Scott Cline
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  • March 2, 2020

    Greetings, In response to your answer to the Code Question of the Day for 02/07/2020, while I totally agree with your answer that a duplex receptacle is two receptacles, I suspect greatly that the argument that generated the question involved a “receptacle outlet” rather than a “receptacle.” For example, 210.52(C)(2)(a) calls for at least one “receptacle outlet” to be installed for the first 9 sq. ft., or fraction thereof, of a residential island or peninsular counter-top or work surface. An island with 10 sq. ft. would call for a minimum of two receptacle outlets. In the seminar setting, I get ask a lot if a duplex receptacle would satisfy this “two receptacle outlet” requirement. The answer to that question is NO based on the definitions of “receptacle” and “receptacle outlet” in Article 100. A “receptacle” is just as you described in your answer and could be one, two, three, four, etc. receptacles mounded on the same yoke (or two yokes). However, a “receptacle outlet” (which is what is called for at places like island and peninsular counter-tops) is defined as “an outlet where one or more receptacles are installed.” To satisfy the requirements for two “receptacle outlets” at a dwelling unit kitchen island, it would call for two separate outlets (or boxes) installed even if both receptacle outlets contained a duplex receptacle (total four receptacles). Regards,L. Keith LoflandChairman-CMP-7IAEI Director of Education
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  • February 28, 2020

    Dear Sirs, I have a question related to Section 110.24(A). Can the marking required by this section be accomplished using a magic marker? This section is vague about specific marking requirements. Thanks, Joe Peters
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  • February 27, 2020

    Greetings Code Question of the Day, Can you help settle a dispute we are having at our office about the Code. Is the ground on a 125-volt, 15-ampere receptacle supposed to be up or down when installed? Some are saying the Code requires the ground up? Interested in your thoughts. Thank you, Benny Purdue
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  • February 26, 2020

    Hello, I enjoy reading the Code Questions of the Day. I understand the NEC is finally addressing reconditioned equipment. Here is my question. Is a panel board permitted to be reconditioned? I'm getting mixed responses about this issue. Follow up question, does the NEC prohibit used equipment? Thanks for any insight you can offer. Alex Cantor
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  • February 25, 2020

    Question from 12-23-2019: If a commercial office furniture manufacturer uses UL approved electrical components but UL has not certified the product/system is the manufacture code compliant for use in a commercial office building? Thank you, Eric Friedman
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  • February 24, 2020

    Can a residential Load Center (sub-panel) be used for a commercial bathroom ? The current Load Center is a residential 100 AMP, and has no problems with its' load. It needs to be changed out because it is old and rusty. Thank you, JP
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  • February 21, 2020

    Thanks for all the information you provide. I was told that all isolated ground receptacles must be orange. Does the NEC contain this requirement? If so what section? Thanks for help clarifying this, Sam Thorpe
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  • February 20, 2020

    If there is no equipment grounding conductor in existing parallel pvc conduits, can one be installed outside of the conduit? 300.3(B) seems to say no. This is a 600-amp feeder in 2 conduits, 120/208-volt 3 phase, 4 wire. Bill Patteuw
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  • February 19, 2020

    Hello all, we were having a discussion in the office about 110.24 Available Fault Current. The code section seems kind of vague, as where the available Arc Fault Sticker should be placed. I said it should be placed at the switch-gear because that's where the first means of disconnect is. They say at the ct cabinet. What say ye? - Tom Labee
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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.

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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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