General Installation Requirements, Part XXIV

Figure 1

Thanks to the work of numerous dedicated individuals, there is a 2017 edition of the National Electrical Code (NEC). This 54th version has been available since August. These days, the Code is revised every three years, but the revision cycle has ranged from one to four years.

More than 4,000 public inputs were submitted. More than 1,200 first revisions were developed from these public inputs. More than 1,500 public comments were submitted to address the public inputs and first revisions. 

It may be time to get a pair of reading glasses (or for some of us, a stronger pair) because the font size is 10 percent smaller in the 2017 edition. The font size reduction resulted in 36 fewer pages; no pages were deleted. 

Gray shading over the text indicates changes. In previous editions, where a large block of information—such as a new article—was added, a vertical line on the margin indicated the new material. In the 2017 edition, gray shading over the letter N is next to the beginning of new provisions. The letter N may indicate something as large as a new article or as small as a new section or subsection.

The new subsection in 110.3 features the gray-shaded letter N. In accordance with 110.3(C), product testing, evaluation and listing (product certification) shall be performed by recognized qualified electrical testing laboratories and shall be in accordance with applicable product standards recognized as achieving equivalent and effective safety for equipment installed to comply with this Code.

There is also a new informational note under this subsection that states the Occupational Safety and Health Administration (OSHA) recognizes qualified electrical testing laboratories that perform evaluations, testing and certification of certain products to ensure they meet the requirements of both the construction and general industry OSHA electrical standards. If the listing (product certification) is done under a qualified electrical testing laboratory program, this listing mark signifies that the tested and certified product complies with the requirements of one or more appropriate product safety test standards. Although this informational note is also new, there is no need to have the gray-shaded letter N next to it because it is directly under the new subsection.

In the 2017 edition, there are global changes, new articles, new sections, relocated sections and revisions to existing sections. One of the global changes in the 2014 edition was changing the voltage threshold from 600 volts (V) to 1,000V in many locations throughout the Code. In the 2017 edition, many more instances throughout the Code were changed from 600V to 1,000V.

Five new articles were added: Article 425, Fixed Resistance and Electrode Industrial Process Heating Equipment; Article 691, Large-Scale Photovoltaic (PV) Electric Power Production Facility; Article 706, Energy Storage Systems; Article 710, Stand-Alone Systems; and Article 712, Direct Current Microgrids.

Black bullets or dots are used the same as they have been in previous editions. Bullets indicate something has been deleted or moved. For example, in the 2014 edition, an informational note stated many terminations and equipment are either marked with tightening torque or are identified as to tightening torque in the installation instructions provided. This informational note is not in the 2017 edition, so a bullet is next to the location of the deleted informational note.

The informational note, which was not a requirement, is now gone, but a new tightening torque requirement has been added. In accordance with 110.14(D), where a tightening torque is indicated as a numeric value on equipment or in installation instructions provided by the manufacturer, a calibrated torque tool shall be used to achieve the indicated torque value, unless the equipment manufacturer has provided installation instructions for an alternative method of achieving the required torque.

This requirement is new and indicated with the “N,” but equipment with lug torque data is not new. Manufacturers have been labeling equipment with tightening torque numeric values for years. In the absence of connector or the equipment manufacturer’s recommended torque values, the tables in Informative Annex I may be used to correctly tighten screw-type connections for power and lighting circuits. The title of Informative Annex I is “Recommended Tightening Torque Tables from UL Standard 486A-B.” The new requirement in 110.14(D) instructs the installer to use a calibrated torque tool to achieve the indicated torque value when the tightening torque numeric values are on the equipment or in the installation instructions.

For example, a panelboard has been installed, and inside the enclosure of the panelboard is a label containing the lug torque data. Because the tightening torque numeric values are provided, the Code requires the use of a torque tool, such as a wrench or driver, to achieve the indicated torque value (see Figure 1).

Section 110.16, which pertains to arc flash hazard warnings, is not new, but the previous requirement is now subsection (A). Subsection (B) applies to service equipment rated 1,200 amperes (A) or more. Like subsection (A), it does not apply to dwelling units. The permanent label (field- or factory-applied) shall meet the requirements of 110.21(B) and contain nominal system voltage, available fault current at the service overcurrent protective devices, the clearing time of service overcurrent protective devices based on the available fault current at the service equipment, and the date the label was applied. 

For example, the service equipment for a new industrial facility is rated 1,200A. Because of the new requirement, a label containing the information in 110.16(B)(1) through (4) is required. The label requirement for service equipment rated 1,200A or more is in addition to the label required by 110.16(A); therefore, equipment rated 1,200A or more shall also have a label to warn qualified people of potential electric arc flash hazards (see Figure 2).

The exception under 110.16(B) states service equipment labeling shall not be required if an arc flash label is applied in accordance with acceptable industry practice. To provide guidance on what is meant by “acceptable industry practice,” a new informational note was added to this section.

In accordance with Informational Note No. 3, acceptable industry practices for equipment labeling are described in NFPA 70E 2015, Standard for Electrical Safety in the Workplace. This standard provides specific criteria for developing arc flash labels for equipment that provides nominal system voltage, incident-energy levels, arc flash boundaries, minimum required levels of personal protective equipment, and so forth.

For example, the service equipment for a new industrial facility is rated 1,200A. An arc flash (or incident energy) analysis has been performed in this facility and arc flash labels are on all the electrical equipment, including the service equipment. Each arc flash label in this facility has a statement to warn qualified people of potential electric arc flash hazards. The labels meet the requirements in NFPA 70E, 130.5(D). 

Because the service equipment in this installation has an arc flash label in accordance with acceptable industry practice, the label required by 110.16(B) is not required. Also, since each label is marked to warn qualified people of potential electric arc flash hazards, the label required by 110.16(A) is not required (see Figure 3).

Next month’s column continues the discussion of electrical installation requirements.

About the Author

Charles R. Miller

Code Contributor
Charles R. Miller, owner of Lighthouse Educational Services, teaches classes and seminars on the electrical industry. He is the author of “Illustrated Guide to the National Electrical Code” and NFPA’s “Electrical Reference.” He can be reached at 615....

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