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It seems like just yesterday that the NFPA Standards Council issued the 2011 National Electrical Code (NEC). However, we’ve moved on to the next one; the 2014 edition was up for approval in August. Revising the NEC is a ton of work for the 19 technical committees during each three-year development cycle. The NEC is in a continuous revision process due to its inherent dynamics. It is a core document in the electrical contracting business, and contractors must be diligent in staying current with the ever-changing rules that affect their operations.
This article is the first of a three-part series that will provide a concise and complete review of some of the more significant changes that have been incorporated into this edition of the NEC. During the 2014 NEC development process, the NEC technical committees acted on 3,745 Code change proposals and 1,625 public comments. There were new articles added to the NEC this cycle. This article series does not contain all of the 2014 NEC changes, but it provides significant, specific changes in the numerical sequence in which they appear.
Voltage thresholds: Increased from 600 volts (V) to 1,000V
The NEC Correlating Committee reactivated the High Voltage Task Group for the 2014 NEC development process and provided a specific assignment to review the entire NEC and submit proposals that change the 600V threshold to 1,000V. The reason behind this global effort relates to some output circuits from renewable-energy sources often exceeding the 600V level. The problem is significant enough that the NEC Correlating Committee determined the need to consider a proposal increasing the long-standing 600V threshold to 1,000V Code-wide.
The task group submitted proposals to each technical committee to consider and act on in the 2014 NEC development cycle. As the NEC technical committees acted on these proposed changes, it became clear that many proposed revisions would have no impact and were accepted. However, some technical committees determined these proposed changes would require substantial work that would require much more time and research to complete than the 2014 cycle would permit; accordingly, they rejected the proposals. The result in the 2014 NEC is that, in many rules, the previous voltage levels of 600V have been changed to 1,000V.
The NEC Correlating Committee understands that these revisions are necessary as the industry is evolving; however, it concedes this project is extensive and will extend into the 2017 NEC cycle and perhaps beyond. The assigned High Voltage Task Group also continues to be active in incorporating many other new medium- and high-voltage requirements throughout the NEC to close gaps and incorporate adequate NEC provisions for installations and systems that no longer are governed by the National Electrical Safety Code (NESC) or applicable utility regulations. The NEC does not typically cover wiring and equipment installed on the line side of the service point; it usually covers installations on the load side of the service point.
The title of the definition of the term “metal-enclosed switchgear” has been changed to simply “switchgear,” resulting in more expanded application of this term. The revised definition also allows for inclusion of the term “switchgear” in existing rules that only include the term “switchboards,” but that requirement covers both types of equipment. The last sentence of the existing definition is more informative than descriptive and, accordingly, has been crafted into an informational note to this definition. All switchgear covered by the NEC rules are intended to be metal-enclosed types. As revised, the definition now applies to all switchgear types, such as metal-clad switchgear, metal-enclosed switchgear and low-voltage power circuit breaker switchgear as indicated in the new informational note. Action by Code-Making Panel 9 on Proposal 9-104a results in a change in the title of Article 408 from “Switchboards and Panelboards” to “Switchboards, Switchgear, and Panelboards,” and the scope was revised to include switchgear. Article 490 was also revised to incorporate the term “switchgear” in place of the term “metal-enclosed switchgear.” Other NEC revisions have been made to replace the term “metal-enclosed switchgear” with “switchgear.” It should be noted that, while the definition of switchgear is located in Article 100, Code-Making Panel 9 maintains technical responsibility for this definition and its use throughout the NEC.
Direct current rules in the NEC
Prior to the start of the 2014 NEC development process, a special task group was specifically assigned to review the existing direct current (DC) requirements in the 2011 NEC and identify any gaps in these requirements. The task group was also charged with making recommendations for specific new Code requirements to fill any of those gaps or provide any needed revisions to existing requirements. This group’s work included researching a number of areas that may be in need of additional DC requirements, such as in Articles 240, 300, 410, 480, 645, 690 and 694. This Code-wide effort involved the participation of members from the appropriate Code-making panels.
This task group’s work resulted in revisions to existing DC requirements in the Code and in various new rules where needs were identified. Examples include the new DC provisions in Article 408 and 480 and new Article 393 that covers low-voltage suspended ceiling power distribution systems and equipment that can be alternating current (AC) or DC.
With the expanded use of DC power from renewable-energy sources and in efforts to reduce energy use and addresses long-range smart grid initiatives, the NEC is expected to see continued expansion of DC wiring rules. Use and installation of DC microgrids is a good example of gaps that still need to be filled in the NEC. It is anticipated that the DC task group will continue this work into the 2017 NEC development process.
New Articles and Annex
Article 393 Low Voltage Suspended Ceiling Power Distribution Systems (ROP 18-10a)
This new article covers the installation of low-voltage suspended ceiling power distribution systems. These systems serve as a structural support for a finished ceiling surface and consist of a conductor support system (small busbars) to distribute power to utilization equipment supplied by a Class 2 power supply. These systems operate at not more than 30V DC and not more than 60V AC and are required to be listed as a complete system that includes all associated fittings and required power supplies.
Article 646 Modular Data Centers (ROP 12-147)
This new article covers modular data centers, including the definition of, the nameplate data for, and the size and overcurrent protection of supply conductors to modular data centers. This article also covers the equipment, electrical supply and distribution, wiring and protection, working space, grounding, HVAC, and the like, located in or associated with a modular data center.
Article 728 Fire Resistive Cable Systems [ROP 3-170]
This new article covers the installation of fire resistive cables, conductors and other system components used for survivability of critical circuits to ensure continued operation during a specified time under fire conditions as required in this Code and in other NFPA standards. Fire resistive cables, conductors and components are tested as a complete system. The system shall be listed. The cables, conductors and components are designated for use in a specific system and shall not be interchanged between systems. Cables, conductors and components shall be suitable for use in accordance with the wiring methods described in the NEC.
Article 750 Energy Management Systems (ROP 13-180)
This new article applies to the installation and operation of energy management systems. Performance provisions related to energy management and conservation in other codes, such as energy codes developed by other model code groups, establish prescriptive requirements that may further restrict the requirements contained in this article. The NEC provides users with a baseline that establishes general requirements for energy management systems and provides a list of loads that should not be controlled by these systems.
Annex J ADA Standards for Accessible Design (ROP 1-191)
Informative Annex J is new and titled “ADA Standards for Accessible Design.” This informative annex is not a part of the NEC requirements and is included for informational purposes only. The provisions cited in this informative annex are intended to assist the Code users in properly considering various electrical design constraints of other building systems, are part of the 2010 ADA Standards for Accessible Design, and are the same as those found in ANSI/ICC A117.1, Accessible and Usable Buildings and Facilities.
Chapter 1 of the NEC includes definitions in Article 100 and general requirements for electrical installations in Article 110. Below are a few significant changes from each of these articles.
Article 100 Definitions
Article 100 Coordination (Selective): “Localization of an overcurrent condition to restrict outages to the circuit or equipment affected, accomplished by the selection and installation of overcurrent protective devices and their ratings or settings for the full range of available overcurrents, from overload to the maximum available fault current, and for the full range of overcurrent protective device opening times associated with those overcurrents.” (ROP 10-5, ROC 10-6)
This definition has been revised to clarify what constitutes selective coordination. The word “choice” has been replaced by the words “selection and installation” to clarify it is selection and installation of overcurrent protection that achieves selective coordination. As revised, this definition makes it clear that selective coordination is across the “full range” of available overcurrents.
Article 100 Premises Wiring (System): A new informational note has been added to the definition of Premises Wiring (System) as follows: “Informational Note: Power sources include, but are not limited to, interconnected or stand-alone batteries, solar photovoltaic systems, other distributed generation systems, or generators.” (ROP 1-61)
No changes have been made to the definition itself, and it continues to address permanently and temporarily installed wiring. The new informational note provides some examples of what constitutes premises wiring systems (sources) and is noninclusive.
Article 100 Retrofit Kit: “A general term for a complete subassembly of parts and devices for field conversion of utilization equipment.” (ROP 18-9, ROC 18-4)
A new definition of “Retrofit Kit” has been added to Part I of Article 100. There are new requirements added to Articles 410 and 600 that include the term “Retrofit Kit.” The definition clarifies what constitutes a retrofit kit for use in electrical signs and luminaires.
Article 100 Separately Derived System: “An electrical source, other than a service, having no direct connection(s) to circuit conductors of any other electrical source other than those established by grounding and bonding connections.” (ROP 5-20, ROC 5-6)
The definition has been revised by combining two sentences into one. Separately derived systems are electrical sources other than the electrical service. The revision clarifies that there is no direct connection to circuit conductors of any other electrical source other than those established by grounding and bonding connections.
Article 110 Requirements for Electrical Installations
110.16 Arc-Flash Hazard Warning: The words “or factory” and “switchgear” have been added to this requirement. The revision clarifies that the marking applies also to switchgear, and it can be either field-applied or applied at the factory. The words “meet the requirements in 110.21(B) and” have been added in the second sentence. Informational Note No. 1 has been revised to include the words “arc flash labeling.” (ROP 1-102, 1-105, 1-107, 1-109, 9-14a, ROC1-47, 1-52, 1-53, 1-54, 1-56)
110.21(B) Field-Applied Hazard Markings: A subdivision (B) titled “Field-Applied Hazard Markings” is added to Section 110.21. Specific requirements now apply to field-applied hazard markings or labels using signal words “danger,” “warning” or “caution” as provided within many NEC rules. New informational notes reference ANSI Z535.4-2011 for guidelines on consistent and effective markings and labels. (ROP 1-114, ROC 1-59, 1-60, 1-61)
110.24 Available Fault Current: A new informational note has been added following 110.24(A). The note clarifies that marking requirements in 110.24 relate to fault current ratings and compliance with 110.9 and 110.10. The maximum available fault current value required by 110.24 is not intended to be used for performing incident energy analysis. (ROP 1-124, 1-121, 1-125, ROC 1-64, 1-66)
110.26(C)(3) Personnel Doors: The value “1,200A” has been lowered to “800A,” expanding requirements for panic hardware on egress doors. The words “panic bars, pressure plates, or other devices that are normally latched but open under simple pressure” have been replaced with “listed panic hardware.” Listed panic hardware is required on personnel doors addressed by this section. The same change occurred in 110.33 for equipment over 600V. (ROP 1-143a, 1-145)
110.25 Lockable Disconnecting Means: A new section 110.25 titled “Disconnecting Means, Lockable” and an associated exception have been added to Part I of Article 110. The new section consolidates the all provisions for lockable disconnecting means through the NEC into one location. Previous NEC requirements that dealt with lockable disconnecting means will now reference 110.25 for consistency and uniform application of the requirements. (ROP 1-130, 1-116, ROC 1-76)
110.26(E)(2)(b) Dedicated Equipment Space: This section has been rearranged and renumbered into a list format to meet NEC Style Manual requirements. A new list item (b) has been added and is titled “Dedicated Equipment Space.” The requirements for dedicated space now apply to equipment installed outside and are similar to the dedicated space requirements for equipment located indoors. (ROP 1-54, 1-55)
About The Author
JOHNSTON is NECA’s executive director of codes and standards. He is a member of the NEC Correlating Committee, NFPA Standards Council, IBEW, UL Electrical Council and NFPA’s Electrical Section. Reach him at [email protected].