National Electrical Installation Standards

Standards as High as Your Own

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  • January 18, 2019

    Re: CQD answer published Thursday, January 10, 2018 - Continuous Loads I'd like to just comment on the CB or OCPD rating of the feeder. The ampacity is determined by the method described, 125% of the anticipated full load. The OCPD then can be selected base on that. For feeders, the standard size value for OCPD can be rounded down from that ampacity rating, not up as required for branch circuits. Best regards, Nick Abbatiello
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  • January 17, 2019

    How is it possible to have a L-G fault on an ungrounded delta system? The delta is ungrounded (no neutral or ground), so physically speaking, how can we have a L-G fault? Thank you Fas Tef
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  • January 16, 2019

    Can I run a class 2 circuit cable (outer sheath around insulated conductors) in same conduit as power based on 725.136(I)(2)? Thanks, Zach
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  • January 15, 2019

    Happy Holidays to all! My neighbor does not believe me that the NEC covers Electrical Holiday Decorations. Can you please share your interpretation 590.3B, so I can kindly remind him that if he installs Holiday Lights in Late November, taking them down in July is a code violation? I really do like Frosty the Snowman, but not in the summer. — Tom Cummins (aka The Grinch)
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  • January 14, 2019

    Re: CQD answer published Wednesday, December 26, 2018 -GFCI Neutral My money says that the 2-pole GFCI breaker will operate just fine with no grounded conductor because there are no line-to-neutral loads as stated by the original question. Remember that inside that GFCI breaker is a small current transformer. All three conductors (two hots and a not) are feed through that CT. Since all the current is flowing through just the two ungrounded conductors, no grounded conductor is needed to allow for correct function. Matthew Hermanson
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  • January 11, 2019

    On a 100 temporary service is the neutral required to be insulated? I have been using SEU cable but the inspector red tagged. His comment was if I could show him in the code book if the neutral was not required to be insulated he would ok the service Alfred Boggess
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  • January 10, 2019

    Clarification on a/c breaker On an air conditioner data plate. It states 35 amp Max OCPD Minimum Circuit Ampacity of 21.5 amps 1) What size OCPD is required for this equipment per Listing and Labeling 2) Am I permitted to put in a lower OCPD than the Max Listed and Labeling on the equipment. Pete Mazzagatti
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  • January 9, 2019

    The transformer in the switchgear has an output at 480 volts of 1203 amperes. The main breaker in the gear downstream of the transformer is a 1600 Amp. With the 80% rating inherent in breakers, this 1600 amp breaker will carry 1280 amperes for continuous loads. Code defines continuous as 3 hours or more, which would apply to the machine operation we are installing. Thus the 1600 amp breaker will have a max rating of 1280 amperes. We are installing a 1000 kva transformer that max load is 1204. By code do I have to run feeders large enough for the 1600 amp breaker or can I run feeders for the 1204 amp draw. Piping directly into my transformer. With no disconnecting means at transformer. Which is 110' away in another room. Thanks for all the great stuff I learned from you. Brett
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  • January 8, 2019

    2017 NEC code question: So I’m installing low voltage 12vac luminaire to a deck post near a pool/spa/inground hot tub. It is located little over 5 feet away from the inside wall and up 8 feet heigh. Art. 411.5 (b) says no less than 10 feet from nearest edge of pool unless permitted by article 680. So when I go to 680.22 (b)(6) it talks about within 5 feet with low voltage Luminaires. But my measurements are outside of 5 feet and 8 feet high . So when I look at 680.22 (b) 4 it looks like it just has to be rigidly attached because I’m over 5 feet heigh? I just don’t know if that means low voltage luminaries also ? What part of 680.22 does my installation fall under? Thanks Steve
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  • January 7, 2019

    Re: CQD answer published Friday, December 21, 2018 -water pipe connection The question inferred water lines were part of the grounding electrode system. If so should the connection be not more than 5-feet from the point of entrance to the building rather than the nearest water line? .per 250.68(C)(1). esps
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  • January 4, 2019

    Re: CQD answer published Wed, December 26, 2018 - Hot Tub Conductor Sizes Friday’ answer revised hot tubs. As an electrical inspector for 24 years I rarely came across a hot tube that did not require full size conductors in accordance’s with 110- 3b. Typically the enforcement required full size conductors be installed from the tub disconnect to the tub, however BEWARE I started to see manufacturer recommendations that require all conductors to be full sized from the source. Always read the manual from the manufacturer and have it available for the AHJ. John Kendall
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  • January 3, 2019

    Re: CQD answer published Thursday, December 20, 2018 -GFCI with no EGC 1) Charlie, the question is probably referring to a two wire system where there is no EGC. I run across this frequently in older homes. Yes, the GFCI will still work without an EGC. Tom Ekstrom 2) What if the person asking the question ask the question in the following way (which is what I think he was trying to ask)…what would your answer be? I have a GFCI outside that I can’t get an equipment grounding conductor to, is that violating and CODE? Regards, L. Keith Lofland
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  • January 2, 2019

    Re: CQD answer published Wed, December 19, 2018 -Meter Disconnect Switches "Charlie" no need to publish my comments but it seems Carl the questioner is mixing apples and oranges. The cold sequencing switch is indeed required in NJ for certain size services but I am not sure it has to have an AIC rating since it is a non-fused switch. The disconnect that is immediately after the meter socket is the one that is a fused switch (or it could actually be a circuit breaker if someone desired that) and that is the one which requires the AIC rating. Also the grounding electrodes and grounding electrode conductors do not appear until the main disconnect is reached. There are no grounding conductors to be installed in the cold sequencing switch. The cold sequencing switch is strictly a safety to be used by the utility to allow their employees to remove and install the meters while not under load. Another point is that the cold sequencing switch is bonded by the neutral or ungrounded conductor similar to the meter socket or CT cabinet bonding. Looking forward t tomorrows response. Keep up the good work and Merry Christmas to all. Rich Van Wert
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  • January 1, 2019

    Re: CQD answer published Monday, December 17, 2018 -Vehicle Electrical Systems Regarding the NEC and vehicular-mounted power outlets. My personal opinions are: 1) The position I believe that CMP 12 is taking regarding this issue is that 90.1 requires us to consider these situations, and that the NEC does indeed cover them. 2) A power outlet provided on a vehicle for use while the vehicle is not in motion, makes the outlet a necessary subject of the NEC. For this use, the "vehicle" is no longer a mobile piece of equipment - a "vehicle" - and has become a "generator." The electrical power available can certainly present significant hazards to life and property. 3) Since these power outlets could easily be up to 120/240-volts, 50-amps, I think that rules should be present in the NEC to address the outlets which can provide dangerous levels of power. I doubt that we are concerned about "cigarette lighter" power levels. 4) Since these outlets are specific to equipment whose primary purpose is vehicular transportation, I think that the EV Article 625, rather than 445 Generators, will be the best suited for rule-making. The technical methods of power production from a vehicle will be significantly different than those of a purpose-built generator. Scott Cline
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  • December 31, 2018

    Greetings and thank you for an enlightening and much appreciated forum. Is there a site where viewing past forum question and answer is possible? Thank you. Kelly Stockwill
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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.

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