A Guide to the 2023 National Electrical Safety Code

Updates cover how to incorporate 5G and other technologies

3 min read
Workers on an electrical line with cloudy sky in background

Since 1914, the National Electrical Safety Code has been a go-to standard for electric and telecom utility companies. The code is updated every five years. The 2023 edition was released on 1 August and will become effective on 1 February.

The NESC updates better protect workers, the public, and facilities during the installation, operation, and maintenance of power and communications supplies. The revisions are designed to help the code remain relevant as new technologies start to be used and safer ways of working are discovered.

Edited and published by the IEEE Standards Association and approved by the American National Standards Institute, the NESC has contributed to major electrical safety codes in most U.S. states, territories, and military bases; the Caribbean; and other entities and countries throughout the world.

Not to be confused with the National Electrical Code, which primarily addresses indoor wiring of homes and businesses, the NESC focuses on the outdoor lines that connect to homes and businesses, the electric supply stations and telecommunications plants, and their overhead and below-ground structures.

Sections of the safety code cover electrical grounding, substations, overhead and underground power lines, and work practices.

Roles dependent on the NESC include:

  • Utility company business leadership, operations management, engineering and line design, crew supervisors, and safety trainers.
  • Providers of power, telecommunications, cable television, wireless services, and the Internet.
  • Railroads, for their power and signaling systems.
  • Manufacturers of electrical equipment and associated product testing agencies.
  • Consultants and contractors that assist in the design and construction of utility lines and infrastructure.
  • State and federal regulatory agencies that provide industry oversight.

What Are the Updates?

  • New rules 190 through 195 cover photovoltaic generating stations.
  • Rule 116c adds an exception for short lengths of insulated power cables and short-circuit protection if the situation involves fewer than 1,000 volts.
  • Rule 320B has been revised to clarify separations that apply to communications and supply in different conduit systems.
  • Table 410-4 is based on the latest arc flash testing on live-front transformers.
  • Rule 092A adds an exception allowing protection, control, and safety battery systems to not be grounded.
  • Rules 234 B1, C1, D1 were revised to better present vertical and horizontal wind clearances, and to coordinate requirements with the new Table 234-7.
  • Rule 120A was revised to provide correction factors for clearances on higher elevations.
  • Table 253-1 has been revised to reduce the load factor for fiber-reinforced polymer components under wire tension—including dead ends—for Grade C construction.
  • Rule 410A now requires a specific radio-frequency safety program for employees who might be exposed.

Some long-standing sections have been made clearer. For tables that include both English and metric values, the inch-foot-pound system is followed by the corresponding metric values in parentheses.

Working groups of NESC subcommittees have been formed to investigate up-and-coming topics such as generating stations and fault-managed power system cables, which might be used for 5G networks.

Handbook Covers Code Changes and Rules

Supplementing the code is the NESC Handbook, which includes commentary by contributors to help users improve their understanding of the code and how it might be applied. Topics include code changes and rules for installing and maintaining electric supply stations. The handbook also provides rules for the operation of electric supply and communications lines and equipment.

A graph that says rules to live byIEEE Standards Association

You can order the 2023 NESC now.

Also available is the NESC Course Program that offers an in-depth look at the rules, regulations, and changes made in the 2023 NESC edition. Access the courses through the IEEE Xplore Digital Library for institutional customers or the IEEE Learning Network for individual learners.

This article was updated from an earlier version.

The Conversation (0)

Get unlimited IEEE Spectrum access

Become an IEEE member and get exclusive access to more stories and resources, including our vast article archive and full PDF downloads
Get access to unlimited IEEE Spectrum content
Network with other technology professionals
Establish a professional profile
Create a group to share and collaborate on projects
Discover IEEE events and activities
Join and participate in discussions

3D-Stacked CMOS Takes Moore’s Law to New Heights

When transistors can’t get any smaller, the only direction is up

10 min read
An image of stacked squares with yellow flat bars through them.
Emily Cooper

Perhaps the most far-reaching technological achievement over the last 50 years has been the steady march toward ever smaller transistors, fitting them more tightly together, and reducing their power consumption. And yet, ever since the two of us started our careers at Intel more than 20 years ago, we’ve been hearing the alarms that the descent into the infinitesimal was about to end. Yet year after year, brilliant new innovations continue to propel the semiconductor industry further.

Along this journey, we engineers had to change the transistor’s architecture as we continued to scale down area and power consumption while boosting performance. The “planar” transistor designs that took us through the last half of the 20th century gave way to 3D fin-shaped devices by the first half of the 2010s. Now, these too have an end date in sight, with a new gate-all-around (GAA) structure rolling into production soon. But we have to look even further ahead because our ability to scale down even this new transistor architecture, which we call RibbonFET, has its limits.

Keep Reading ↓Show less