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Changes to the 2017 NEC®

A rigorous process of review keeps the National Electrical Code® up-to-date with new technologies

Throughout the United States and around the world, NFPA 70®, National Electrical Code® (NEC®) sets the foundation for electrical safety in residential, commercial, and industrial occupancies. The 2017 edition of this trusted Code presents the latest comprehensive regulations for electrical wiring, overcurrent protection, grounding, and installation of equipment. In fact, more than 4,000 public inputs and 1,500 comments went into the 2017 edition of the Code. Hundreds of updates and five all-new articles pave the way to a safe and efficient electrical future. 

What's changed?

The 2017 edition of the National Electrical Code addresses the advancement of privately-owned wind and solar power generation and distribution equipment - including coverage of higher voltage systems that were once only the utilities' domain. The new consumer role is a major factor in energy decentralization, and expanded NEC coverage is vital for designers, engineers, contractors, and AHJs. NFPA Journal® looks at significant changes in the 2017 NEC,

The 2017 NEC includes usability features to aid the user. Changes other than editorial are indicated with gray shading within sections. An entire figure caption with gray shading indicates a change to an existing figure. New sections, tables, and figures are indicated by a bold, italic in a gray box to the left of the new material. An N next to an Article title indicates that the entire Article is new. Where one or more complete paragraphs have been deleted, the deletion is indicated by a bullet (•) between the paragraphs that remain.


New 2017 Articles

  • Large-Scale Photovoltaic (PV) Electric Power Production Facility (New Article 691) covers systems that produce at least 5 megawatts (MW) of power, or enough to power 800+ U.S. homes.
  • Energy Storage Systems (New Article 706) governs ESS installation, disconnection, shutdown, and safety labeling.
  • Stand-Alone Systems (New Article 710) covers power production sources that are not connected to the grid, including PV and wind-powered systems.
  • Direct Current Microgrids (New Article 712) concerns independent energy distribution networks that allow the utilization of power from dc sources to direct-current loads. Microgrids are on the rise worldwide.

Other revisions to the 2017 NEC protect the public and workers from deadly hazards, including:

  • new labeling, such as detailed arc flash hazard warning on equipment, helps workers and supervisors assess electrical risks.
  • new minimum space clearances for equipment installation clarify the safeguards needed to protect installers and maintainers.
  • fixed Resistance and Electrode Industrial Process Heating Equipment (New Article 425) presents needed regulations for industry.
  • revised provisions for AFCI and GFCI protection improve electrical and fire safety in homes.

A history of electrical safety

“In 1911 , the NFPA was asked to take over administration of the National Electrical Code® (NEC), which had been started by the Underwriters National Electrical Association in 1892. Certainly, the NEC is an important publication of our Association, and its publication year is yet more evidence that the system of consensus-based Standards writing not only works, but is at the same time the most democratic form of self-regulation in the United States. The process of preparing the NEC for the public marketplace is time-consuming and laborious, yet the process itself is an essential aspect that ensures the level of acceptance the National Electrical Code enjoys throughout the land. Good things take time. and we are well served by the effort that goes into the NEC.” 

- "A Brief History of NFPA Codes and Standards", NFPA's Fire Journal, May 1986

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