This article is part 2 in a series that examines some of the more significant revisions and new requirements in the 2017 National Electrical Code (NEC). This piece reviews some significant changes in Articles 100 and 110.
 Visit www.ecmag.com/magazine/articles/article-detail/codes-standards-2017-nec-significant-changes for this full series.


Article 100

Article 100­—Definitions


Multiple definitions of words and terms pertaining to hazardous (classified) locations previously located in 500.2 have been relocated to Article 100. The words “as applied to Hazardous (Classified) Locations” have been added in brackets following each relocated term.


Article 100—Readily Accessible 


The definition of “readily accessible” has been revised. The definition maintains most of its existing text and now includes “other than keys.” A new informational note addresses the common practice and use of keys in gaining accessibility under controlled conditions.


Article 100—Field Evaluation Body and Field Labeled


New definitions of “field evaluation body” and “field labeled” have been incorporated into Article 100. These definitions have been developed from concepts derived from terms in NFPA 790, Standard for Competency of Third-Party Field Evaluation Bodies.


Article 100—Structure 


The definition of “structure” has been revised by adding “other than equipment.” The revision provides a clear differentiation between what constitutes electrical equipment as compared to structures.


Article 100—Substation 


The title of Part II of Article 100 has been changed from “Over 600 Volts, Nominal” to “Over 1000 Volts, Nominal.” The previous definition of “Substation” has been relocated from Part I to Part II.


The definition has been revised to clarify its physical characteristics and how it is usually intended to perform. A substation is defined as an assemblage of equipment (e.g., switches, interrupting devices, circuit breakers, buses and transformers) through which electrical energy is passed for the purpose of distribution, switching or modifying its characteristics. A substation can be an outdoor substation in an enclosure such as a fence, or it can be a unit substation.


Article 110—Requirements for Electrical Installations


110.3(A) Examination


A new informational note No. 1 has been added to 110.3(A)(1). Previous Informational Note No. 1 has been renumbered as Informational Note No. 2. The new note clarifies that the term “equipment” used in this section can apply to new, reconditioned, refurbished or remanufactured equipment.


110.3(C) Listing


The title of 110.3 has been revised to include the words “(product certification).” A new Subdivision (C) and associated informational note have been added to Section 110.3.


The revision clarifies that listing (product certification) must be performed by recognized, qualified electrical testing laboratories, and the new informational note indicates that the Occupational Safety and Health Administration (OSHA) provides a list of such qualified laboratories.


110.14(D) Installation


A new subdivision (D), “Installation,” has been added following 110.14(C). This subdivision incorporates mandatory torque tightening requirements for electrical terminations in accordance with the manufacturer’s instructions. It also allows for alternative methods as provided in the instructions. The informational note to 110.14 has been deleted because it is no longer necessary.


110.16(B) Service Equipment


A new (B), “Service Equipment,” and informational note have been added to 110.16. The provisions in 110.16 now require more installation-related detail and information for determining arc-flash energy levels and required PPE. The nominal system voltage, available fault current, the service overcurrent protective device clearing time, and the label date must now be included in the arc-flash warning label. The informational note references NFPA 70E for specific criteria related to arc-flash labels and determining appropriate PPE.


110.21(A) Equipment Markings


The title of subdivision (A) has been changed to “Equipment Markings” from “Manufacturer’s Markings.” Section 110.21(A) has been renumbered as list items (1) and a new list item (2) with a new exception and informational note. New list item (2) provides marking requirements for reconditioned equipment including the responsible organization and date of reconditioning.


110.24(A) Field Marking 


A new last sentence has been added to 110.24(A) addressing calculations. The additional requirements are intended to document the calculation and make it available to those authorized to design, install, inspect, maintain or operate the system. The maximum level of available fault current can be obtained from published utility data or by use of calculation methods.


Visit http://goo.gl/U3vLo7 to view all of the proposed revisions.