National Electrical Installation Standards

Standards as High as Your Own

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  • October 24, 2018

    If a basic disconnect has cables terminated inside, but is not terminated at the main. Does this device need to be locked out if it is in the "off" position? This is temporary power in a "green" zone, and the client does not want to lock out the disconnect that feeds motors they are wanting to run intermittently. I told them that if a disconnect is terminated, regardless if it is live, must be locked out. It has to be treated as live correct? They are just using the disconnect basically as a switch rather than a means of on/off. Rob Poston
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  • October 23, 2018

    We hang three unit heaters there are ten feet in the air where do you put the service switch? We install them on the unit. They want me to put the service switch on the wall down at six feet off the floor and 30 feet from the heater is this right? Bruce Henretty
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  • October 22, 2018

    I'm an electrician for the government and I been fighting this issue with our building manager and a project manager about multi branch circuits. They have been installed and are used to supply power to nonlinear loads to lighting and also receptacles which feed medical equipment. They have allowed electrical contractors to use 3 ungrounded conductors and one shared neutral from a 4 wire 3 Phase systems using 3 pole type breakers sharing one neutral. Violation of article 410.130(G)(2) none of the neutral conductors have a disconnection means. This was back in 2011, but they still continue to allow this practice, the electrical contractor has stipulated that the installation are in no way in violations to the NEC. So even though 225.33(B), 230.71(B) and 240.15(B), permit two or three single-pole switches or breakers on the multiwire branch circuits that are capable of individual operation—one pole for each ungrounded conductor and one multipole disconnect—provided these devices are equipped with identified handle ties or a master handle to disconnect all ungrounded conductors. Does that mean that’s its ok to use a three pole breakers, with ties, marked in accordance to the code to be use to feed lighting and receptacle circuits that use 3 ungrounded conductors and a share a neutral. Most of the buildings are medical in natural, 3 are dental clinics that do provide surgical care and main building was a hospital but was reduced to clinical services now. Thanks any help to explain if this practice of using a multi branch circuit is still in accordance with new 2017 NEC standards and was this practice allowed back in 2011 Adolfo Munoz
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  • October 19, 2018

    Orientation of receptacle. Ground up or down? Vito Vacirca Jr
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  • October 18, 2018

    Article or reference: all of NFPA referring to proper marking of emergency circuits at source and equipment. to include year adapted, volume, and page or article number. J Marranca
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  • October 17, 2018

    Charlie, Thank you for your service...enjoyable and very informative. Section 300.3(B) discusses conductors of the same circuit and in general, requires that all conductors (including the grounded conductor and all equipment grounding conductors and bonding conductors) to be contained within the same raceway, auxiliary gutter, cable tray, cablebus assembly, trench, cable, or cord unless otherwise permitted in accordance with 300.3(B)(1) through (B)(4). An exception under 300.3(B)(1) - Parallel Installations - allows conductors that are installed in underground, non-metallic raceways to be arranged as isolated phase installations as long as the raceways are installed in close proximity and comply with 300.20(B). Section 300.5(I) discusses conductors of the same circuit in underground installations. This section also requires all conductors of the same circuit (including the grounded conductor and all equipment grounding conductors) to be installed in the same raceway or cable "or shall be in close proximity in the same trench." Exception No. 2 under this section, however, allows isolated phase, polarity, grounded conductor, and equipment grounding and bonding conductor installations in non-metallic raceways in close proximity where conductors are paralleled as permitted in 310.10(H), and where the conditions of 300.20(B) are met. Now to my question: For an underground 3 phase, 5 wire installation (3 phase conductors, an equipment grounding conductor, and a grounded conductor), can the 3 phase wires and the equipment grounding conductor be installed together in a single underground PVC conduit and the grounded conductor be installed in a separate, adjacent underground PVC conduit? The conductors are "installed in close proximity in the same trench" per the last sentence of Section 300.5(I) and this also appears to meet the general intent covered by Exception No. 2 under Section 300.5(I). However, this is not a parallel installation and each phase is not isolated. All phase conductors (and the equipment grounding conductor) are grouped together in one underground PVC conduit and the grounded conductor (the neutral) is installed in a separate underground PVC conduit with both conduits being side by side (i.e. in close proximity in the same trench). Thanks, Chris DeWeese
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  • October 16, 2018

    A metal cabinet contains service conductors, their splices, and current transformers (CT), and is located upstream of an 800-amp service disconnecting means. The CT cabinet has only PVC raceways entering and exiting the enclosure, and the engineered drawings do not show any supply-side bonding jumpers in the PVC raceways. Is it correct to assume that this metal CT enclosure must be connected to a supply-side bonding jumper? If so, what is the correct size bonding jumper? Should supply-side bonding jumpers have been included in the drawings? Although NEC Table 250.102 (C)(1) provides sizes of supply-side bonding jumpers, there seems to be no specific text section that references this table for metal enclosures. I have looked at 250.80, 250.92, and 250.102 (C). Can you help me connect the NEC dots to size supply-side bonding jumpers to metal CT enclosures? Curtis Lichty
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  • October 15, 2018

    Re: CQD answer published Monday, October 8, 2018 -GFCI Protection in Kitchens For the question posted for Friday, October 5, 2018, "Do all circuits in a Kitchen need to GFCI, or only those at the counter top?" Your answer didn't include 210.8(D) Kitchen Dishwasher Branch Circuit. GFCI protection shall be provided for outlets that supply dishwashers installed in dwelling unit locations. To me, since the dishwasher receptacle could be outside of the 6' to sink rule then 210.8(D) makes the use of GFCI protection an absolute. Rich
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  • October 12, 2018

    Re: CQD answer published Thursday, September 27, 2018 -Tray Cable I have seen TC cable that looks and smells like SO cord. David Green
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  • October 11, 2018

    Re: CQD answer published Wednesday, September 26, 2018 - I think this answer is incomplete. Shouldn’t the last sentence reference the exception for 404.14(F) for clarity? Michael D.Lewis
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  • October 10, 2018

    Re: CQD answer published Wednesday, September 14, 2018 -Suspended Ceiling Luminaires 3 Charlie, we have a local "more restrictive local law" (MRLS) in the City of White Plains that requires all recess lay in fixtures to be independently supported with two #12 wires or jack chain. The reason is our local firefighters have been struck by falling fixtures, some with sharp edges, during overhaul. This requirement was enacted during the early '70's when the fixtures were heavier and sometimes as large as 3' x 5' with eight lamps and four ballasts. Since that time, it has become "standard" in the surrounding communities for the local inspection agency to ask for the same level of support. Ours is the only one that is recognized by the State of NY as an MRLS and is enforceable. The other towns make it a "verbal" requirement. Richard Mecca
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  • October 9, 2018

    Re: CQD answer published Wednesday, September 14, 2018 -Suspended Ceiling Luminaires 2 Good morning, I enjoy the Forum and all that you do. I am not sure if in today's answer you misspoke or perhaps we have a different interpretation of 410.36(B). As I understand it, the section covers ceiling systems used to support luminaires. If the luminaire is supported independently, such as by wires on opposite corners, it is supported by the wires and not by the ceiling system. As such, it is not required to secure the luminaire to the framing member. In this case, in the event a fire fighter removes all or a portion of the ceiling grid in the course of fighting a fire, the luminaires would remain in place if unattached to the grid. If attached, removing the grid would also bring down the luminaires. Seismic concerns are also covered by this logic. On the other hand, if the luminaire is supported solely by the grid, it must be secured to the grid per 410.36(B). J Grant Hammett
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  • October 8, 2018

    Re: CQD answer published Wednesday, September 14, 2018 -Suspended Ceiling Luminaires 1 Charlie, In regards to the question from Sep 13, 2018 about supports for light fixtures in a suspended ceiling grid. I offer the following standard found in most AIA specifications for acoustical tile ceilings and grids. That standard is ASTM C636. It is also part of most manufacturer’s guidance that the grid needs to be installed according to this standard. The meat of the standard with regards to this question says: “supports on main tees should be at 4 foot intervals and Fixtures shall not be supported from main runners or cross runners if the weight of the fixture causes the total dead load to exceed the deflection capability of the ceiling suspension system. In such cases, the fixture load shall be supported by supplemental hangers within 6 in. [150 mm] of each corner, or the fixture shall be separately supported. “So, whomever inspects the ceiling grid should call out the problem to the ceiling installer. If the fixture exceeds the dead load rating, the ceiling installer should add the supplemental wires, unless the specifications call for the fixture to be supported independently of the grid (most often in seismic areas) when the electrical contractor should be providing the fixture supports. The ceiling grid installer has a reflected ceiling plan showing the location of the lights in it. He should be able to bid accordingly. In our specifications (we are not in a seismic area), we call out that the ceiling installer shall provide the wires at the corners regardless of the dead load rating. We coordinate with the architects to make sure they have the wording in their specifications. Thank you, Alex
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  • October 5, 2018

    Do all circuits in a Kitchen need to GFCI, or only those at the counter top ? Mark Burford
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  • October 4, 2018

    What should my clearance be for a transformer Westchester county New York Jeffrey Hachey
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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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