Every Three Years: Significant Changes in the 2020 NEC

By Michael Johnston | Jun 15, 2019
EV Electric Vehicle Photo Credit: Shutterstock / Chesky
This article is the first in a series that examines some of the significant revisions and new requirements in the 2020 NEC

Every three years, the National Electrical Code (NEC) is revised and often expanded. As the 2020 NEC development cycle comes to a close, the process’ final stages unfold. This article is the first in a series that examines some of the significant revisions and new requirements in the 2020 NEC. Note that the 2020 NEC development process is still open and is not final until the completion of the NFPA Technical Session on June 20, 2019, and the subsequent issuance by the NFPA Standards Council in August 2019.

The NFPA received 3,730 public inputs recommending Code change, resulting in 1,400 first revisions (FR). The NFPA also received 1,930 public comments, producing 634 second revisions. Seventy-three correlating FRs and four new articles emerged in the 2020 NEC.

Many of the changes and new rules address new technologies, such as expanded use of energy storage systems and equipment, microgrid installations, and large-scale photovoltaic system installations. The following is a summary of the new articles in the 2020 NEC.

Article 242—Overvoltage Protection

Articles 280 and 285 from the 2017 NEC have been combined into Article 242, “Overvoltage Protection.” The article has three parts: “General,” “Surge Protective Devices (SPDs) 1,000 Volts or Less,” and “Surge Arresters Over 1,000 Volts.” Technical responsibility for Article 242 and its associated definitions in Article 100 has been shifted from Code-Making Panel (CMP) 5 to CMP 10.

Article 311—Medium Voltage Conductors and Cables

Article 328 from the 2017 NEC was deleted, and its contents was relocated to a new Article 311, “Medium Voltage Conductors and Cables.” This article also incorporates requirements for medium voltage cables and conductors rated over 2,000 volts, which were formerly located in Article 310. This new article covers the use, installation, construction specifications, and ampacities for Type MV medium voltage conductors and cable.

Article 337—Type P Cable

A new Article 337, “Type P Cable,” has been added to NEC Chapter 3. This article addresses the use and installation of Type P cable (marine shipboard cable). Type P cable has been commonly used in land-based oil and gas rigs for over four decades, but the NEC has never addressed its permitted use. Type P cable is limited to industrial installations and hazardous locations.

Article 800—General Requirements for Communications Systems and Article 805—Communications Circuits

Article 800 has been revised to combine all of the common general requirements from all of the chapter eight communications articles into a single article. The remaining specific rules in former Article 800 have been included in a new Article 805, “Communications Circuits.” This revision addresses usability of the NEC rules for all communications systems and removes a significant amount of redundancy. The revisions resulted from work of a usability task group specifically assigned by the NEC Correlating Committee.

Section 90.2(A)(5) and (6)

Section 90.2(A) provides information about what the NEC covers. Two new list items (5) and (6) have been added to Section 90.2(A). List item (5) addresses installations providing shore power to watercraft in marinas and boatyards including monitoring leakage current. A new (6) in 90.2(A) to addresses installations used to export power from electric vehicles to premises wiring.

Bidirectional flow of power is typically accomplished using utility interactive inverters. Revisions in Article 625 resulted in the need to provide clarification in the NEC’s overall scope as it applies to processes and equipment that is used to export power from electric vehicles to the premises wiring. Where an electric vehicle supplies power to wiring systems, it is acting like a generator. The NEC is clear that generators connected to premises wiring must meet all applicable requirements.

Article 100—Scope

NEC Article 100 covers definitions of terms that appear in more than two articles.

Article 100’s scope has been revised to indicate definitions are also provided in the .2 section of some articles. The scope’s second paragraph has been expanded to include a new Part III that includes definitions specifically applicable to Hazardous (Classified) Locations. Moving all of the definitions from the chapter five hazardous locations articles brings chapter five into compliance with the NEC Style Manual and enhances usability. Both changes revise the scope to align with the representation contained in Article 100. CMP 14 retains technical responsibility of the defined words and terms contained in new Part III of Article 100.

My next column will continue this series on the 2020 NEC changes.

About The Author

A man, Mike Johnston, in front of a gray background.

Michael Johnston

NECA Executive Director of Codes and Standards

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].






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