National Electrical Installation Standards

Standards as High as Your Own

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  • April 23, 2019

    Can a new Packaged RTU HVAC unit with a 208-230/3 rated CSA data tage be applied to a grounded "B" phase 240 v delta service without modification to the CDA unit label?Paul Willmus
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  • April 19, 2019

    What is the correct way to support lay in light fixtures in a grid ceiling?Steve Green
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  • April 18, 2019

    Can the codes officer issue orders to install both an out-door entrance light at front door and to installed GFIC outlet outside of property, single family? House was built about 100 yrs ago. some upgrades were done in past years.Larry Shroyer
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  • April 17, 2019

    In the electrical panel (which Has GE breakers installed, I notice that 2 of the double pole breakers for the pool are of different manufacturer. Is this legal according to the electrical code. Thank you,Gary Lehnerz
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  • April 16, 2019

    Hello! Can I locate the panelboard in residential installation inside the laundry room?Edgar González
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  • April 15, 2019

    The answer to last Friday's question did not get published on Monday so we are publishing Friday's question again: Apparently Monday's question was published twice. DOES THE NEC PERMIT THE USE OF GLUE ON NONMETALLIC FLEX INSTEAD OF NONMETALLIC FLEX CONNECTORS USED TO ENTER CONDULETS BY GLUING.JAMES KRACH
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  • April 12, 2019

    Re: CQD answer published Fri day, March 29, 2019 -Device Hi all great job here. Regarding your answer to Safa on 03/28/19 I must expand upon your answer and say that a multipole breaker is a single device. For example, while a 2-pole breaker might consist of two single pole breakers, it is a factory constructed single assembly. When I buy a 2-pole breaker I am charged for one item, not two. I understand the wording might be tricky, but while a 2-pole breaker is a single device it is also counted as two overcurrent devices. Also, you made a reference to article 250.15 which I believe is a typo that should read 240.15 so you might want to correct that. Thanks again for all you do for us. Richard Cressotti
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  • April 11, 2019

    How many grounding rods are required in Robeson County? Also we have a lot of pig iron In our ground. What is the best method of putting the rod in the ground? Donna Clark
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  • April 10, 2019

    Re: CQD answer published Wednesday, March 27, 2019 -Large equipment 1) Charlie, Thanks for all work that you put into CQD, I look forward to it every day! My understanding is that busway is a wiring method and that 110.26(C)(3) is intended to apply to the equipment that houses switches or breakers. 110.26(C)(3) states “equipment rated 800 A or more that contains overcurrent devices, switching devices, or control devices…” The 1200 Amp busway itself does not include the overcurrent device, the 400 Amp bus-plug is the equipment containing the OCPD. For an 800 Amp bus-plug I would agree with the response given, but for a 400 Amp plug in unit the answer provided is not the typical understanding I’ve had about how to apply the rule in 110.26(C)(3). I wonder if the answer would have been the same if we had a 1000A riser with cable and conduit to a tap box that is close coupled to a 200A safety switch? Thanks again. Rod West 2) Charlie, You great service to those of us who merely think we know the Code! If I may be so bold as to ask you to consider another interpretation to 110.26 (C) in reference to the 1200A bus and the 400A bus plug in the question. NEC 110.26 (C) (2) Large Equipment rated 1200A and more and over 6-feet wide that contains overcurrent devices, switching devices, etc. This requires one door at each end of the working space unless there is an unobstructed egress or there is extra working space. Highlighting added for emphasis. NEC 110.26 (C) (3) Personnel doors for areas with equipment rated 800A or more that contains overcurrent devices, switching devices, or control devices. This requires personnel doors within 25-feet of the equipment to open in direction of travel and have listed panic hardware. Highlighting added for emphasis. The two sections I am referencing here hinge on the definition of “contains”. The bus in the question is an enclosure that contains only bus bars rated 1200A. The bus plug in the question is an enclosure that attaches to the outside of the bus and contains bus, switching components, and overcurrent devices rated 400A. As I understand bus ducts, they do not contain the items that are indicated in 110.26 (C) (2) or (3). The bus plug is rated 400A and is below 800A that would require personnel doors to meet the requirements of 110.26 (C) (3). Please consider my interpretations of the question for Tuesday, March 26. Thank you, Rodney Welch
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  • April 9, 2019

    Is working clearance in accordance with NEC Section 110.26 (A) required for a simple home breaker panel? The only internal access is when it is deenergized. Thanks, Tony Armendariz
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  • April 8, 2019

    I have 200 amp Panel The neutral and ground wire for each circuit are together on the ground bar is this ok by code DEAN CARNES
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  • April 5, 2019

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  • April 4, 2019

    Charlie, Please refer to the table. This breaker has AIC ratings for several voltages. We are trying to apply this breaker to a 480 volt high resistance grounded system. This breaker table shows a UL 489 AIC rating at a nominal voltage of 480 volt. So this looks like it can be applied in my system. What I am concerned about is the 600/347 rating listed in the table. Since this is a slash rated breaker and the lower value is less than 480 volt I am not sure this breaker can be applied in the 480 volt HRG system and if used could be a violation of 240.85 and a possible safety hazard. Is this slash rated breaker be used on a 480 volt HRG system? Thank you. Jeff
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  • April 3, 2019

    Can u give me the article nr for a panel to be balanced Aancoinc
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  • April 2, 2019

    Duplex outlets in residential Bedrooms : any wall over 2' requires duplex What if they 2'-6" wall is totally covered up by 2'-8" door swing ( pocket door frame in way of duplex) Robert Gaskill
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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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