National Electrical Installation Standards

Standards as High as Your Own

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  • June 6, 2017

    Is back of the kitchen island or peninsula considered a wall space thus requiring an outlet in addition to the outlet(s) installed on the sides? Stefan Hamran
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  • June 5, 2017

    Do all alternate power sources need to be labeled and where can I find it in the book? Even if its 120v? Matthew Thomson
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  • June 2, 2017

    Re: CQD answer published Friday, May 19, 2017 -Parallel Equipment Grounding Conductors Good day Charlie, I enjoy reading your Code Question of the Day every morning prior to performing my inspections for the day. In reference to your response to Greg McMurphy, dated 5/18/17, I respectfully disagree with your response and example. To clarify, 250.122(F) states where conductors are installed in parallel in multiple raceways the Equipment Grounding Conductor must be sized per Table 250.122, and installed in each conduit fully sized. For example, I have a 500 amp Circuit Breaker, the EGC shall be sized to a #2 AWG, the phase conductors would be sized to 800 KCMIL. Instead of running 1 set of 800 KCMIL conductors, I chose to use 250 KCMIL conductors paralleled. Per 250.122(F) I’m still required to use #2 AWG EGC in both conduits. The example you gave of adding the total sum of both parallel conductors is only used when applying the provisions of Table 250.66, which is used to calculate the size of the Grounding Electrode Conductor. If I were to increase the phase conductors due to voltage drop, then per 250.122(B) I would need to increase the Equipment Grounding Conductor sized proportionately to the phase conductors. Using the same scenario for the 500 amp Circuit Breaker. I increased the parallel conductors from 250 KCMIL to 300 KCMIL, this would be an increase of 120 %. Per Table 8 of Chapter 9, a #2AWG conductor has a circular mils of 66360 multiplied by 120% = 79,632 circular mils, the conductor size that correlates closest to that sum would be #1 AWG. I would then have 300 KCMIL phase conductors and a #1 AWG EGC paralleled. Thank you, Mike Cross
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  • June 1, 2017

    Pertaining to 240.21(C) ...... "without overcurrent protection at the secondary, as specified in 240.21(C)(1) through (C)(6)....". Question, the way I read this the installation need only meet one of the six parts to comply. [ the installation does not meet (C)(1) but does meet (C)(2), so I am still legal to use only primary overcurrent protection ] Correct ? Edward Ryding
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  • May 31, 2017

    Thank you for providing this form for code questions! It is helpful for all involved. In regards to panic hardware required within 25 feet of work space of electrical equipment rated over 800 amps-NEC 110.26(C)(3): Do all egress doors within 25 feet of work space need to be equipped with panic hardware even if the door does not lead directly from an electrical room. Another words, if there is panic hardware on the door leading out of the electrical room into an office and the door leading from the office to the hall was less than 25 feet from the work space would it need panic hardware as well even though there is no electrical equipment in the office? The picture on page 39 of the Analysis of Changes to the 2014 NEC seems to imply this requirement. Thanks! Mike
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  • May 30, 2017

    Re: CQD answer published Monday, May 15, 2017 -Accessible Fitting Good morning, How does a listed transition fitting differ from an ordinary coupling? It is not necessary to maintain access to couplings or connectors so why is it necessary for the transition fitting? The "fitting" referenced in 300.15(F) is something to be used "in lieu of box or conduit body". The transition fitting is neither. J Grant Hammett
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  • May 26, 2017

    Hi Charlie, I have been told that you can round down when doing load calculations. It that true? Thank You, Danny
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  • May 25, 2017

    How does the GFCI protection requirement for receptacles within 6 feet of a sink apply to the new washing machines that have built in sinks? Mike Dowdy
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  • May 24, 2017

    Thank you for this invaluable service to the electrical trade. Could you please clarify 430-109(B). Is it required the branch circuit overcurrent device be in sight of the motor to suffice as the disconnect means or is it allowed to be out of sight or capable of being locked in the open position if out of sight? Kelly Stockwill
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  • May 23, 2017

    Re: CQD answer published Tuesday, May 16, 2017 -Locking Doors In response to Doug Gerke's question related to keeping the door closed/locked for safety, a Purdue student named Wade Steffey was electrocuted and killed in a dorm due to contact with a transformer. It could have been prevented had the door been properly latched and locked. While not Code or OSHA required, it only makes sense to utilize the safety measures available. Maybe sharing Wade's story will help save another life in this situation. https://news.uns.purdue.edu/x/2007a/070320PoliceSteffey.html Thanks, Alec Hoffman
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  • May 22, 2017

    Is it legal to run SO cord in a Power Pole ? Power Pole brings power and data from open ceiling at a Big Box Store.....we are using SO cord because manager wants flexibility to move registers in the future. SO cord has plugs at both ends and connects to a twist lock receptacle. Don Nelson
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  • May 19, 2017

    Hi Charlie, I am needing help with the specific code article(s) that permits a thermostat wire to be spliced without a box or enclosure. Thank you, Jeff Shaw
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  • May 18, 2017

    Charlie, Thanks for your work on this important public service. When feeder or branch circuit conductors are run in parallel, does the EGC ever have to be larger than the ungrounded conductors? The folks that wrote the code handbook seem to think so, BUT the last sentence of .122(F) states "Each equipment grounding conductor shall be sized in compliance with 250.122." That takes you to 250.122(A) first sentence that states"shall not be smaller than shown in Table 250.122".... but that sentence has a commma and we need to keep reading to the end. Immediately following the mandatory use of the column is the statement "but in no case shall they be required to be larger than the circuit conductors supplying the equipment." It is in the same sentence. I think "in no case" means just that, in no case will the table drive you to size an equipment grounding conductor larger than the circuit conductors. Including the case of the parallel conductors. If you go back to the more clear wording of 250-95 in previous versions of the code ( I went to the 1993), back before the removal of exceptions was made for "clarity and usability" the intent is much more clear. Exception 2 has the wording that is now permissive language in .122(A) and exception 2 to 250-95 applies to the parallel conductor statement. Thanks for giving us your take on this issue. Greg McMurphy
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  • May 17, 2017

    Good morning Charlie, I am a bit mystified that Aluminum is still allowed as a service supply or even as cables to lights/switches/outlets? This is based on my experience from the original World Trade center incoming services being aluminum and were the cause of several fires due to Ali-corrosion from the “brass Allen keyed bolts” into the “cad/zinc plated receptacles” and then holding the “Ali conductors”- not a solid conductor but multi-wired, were squeezed with several strands fractured. Even some of the service Buses were Ali [Dissimilar materials causing cathodic corrosion]. Lots of white Ali powders around and on the bottom of the main cabinets. An 800 Amp service is nearly always found in industrial/office type situations and probably very rarely check for Impedances/Corrosions! Seems strange the NEC still allows/recommends Ali conductors and some are even copper coated (still corrode if the copper is broken by the knurl on the securing Allen Bolt or screw. What are your thoughts on the uses [none of the Ali conductors we have seen were “tinned” or “tinned then ferruled”] We only use copper conductors and Brass Buss Bars for incoming service distribution busses and conductors (yes, we do put some electrical corrosion greases over these terminations to stop the copper Verdigris forming)? Look forward to your response. Sincerely yours, Geoff
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  • May 16, 2017

    Re: CQD answer published Friday, May 5, 2017 -Ampacity 90 Degree Insulation Thanks for the service that you provide for the industry. I believe that a clarification is needed for your answer to the Thursday May 4 question. In your answer to the question regarding parallel service conductors you suggested using conductors rated at 90 degrees. It is my understanding that the 90 degree rating may only be used if you know that the terminations are also rated 90 degrees per 210.14. That is an important distinction that should be made. Don Haskin
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ABOUT CQD: NECA’s Code Question of the Day (CQD) is a leading National Electrical Code® forum for NECA and the industry. The CQD generates a lively dialogue and relative practical and Code-based responses to an ever-increasing and interactive audience.

IMPORTANT NOTICE: All answers are based on the latest edition of the National Electrical Code®, unless the question requests a response based on a specific edition. This correspondence is not a formal interpretation of the NEC®. Any responses expressed to the questions are opinions and do not necessarily represent the official position of NECA, NFPA, or any technical committee. In addition, this correspondence is neither intended, nor should it be relied upon, to provide professional consultation or services.

ABOUT CHARLIE: 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. Charlie was also a member of NECA’s Academy of Electrical Contracting. Charlie’s experienced team of industry experts keep the CQD dialogue and discussions active and informative in the spirit of the man himself, as he wanted.

NECA STANDARDS: NECA publishes the National Electrical Installation Standards™ (NEIS™), a series of ANSI-approved performance and quality standards for electrical construction. Visit NECA-NEIS.org for more information. NEISÔ can be purchased in three formats: as paper books, on CD, or as electronic downloads.

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