Tdworld 2939 Substation5

The Ongoing Refinement of the National Electrical Safety Code

May 19, 2015
Refinement of the National Electrical Safety Code® (NESC®) never stops.

Refinement of the National Electrical Safety Code® never stops. 

Among the key changes that were introduced in the current, 2012 edition of the NESC were clarifications where the NESC applies in relation to the NEC, revised requirements around equipment grounding, clarification of certain fencing requirements in substations, illumination requirements for generating stations and substations, new arc flash protection requirements for worker exposures below 1000 volts and changes to minimum approach distance (MAD) tables. Now, work is well on its way toward the next, 2017 edition of the code. Proposed changes to adapt for new challenges and technology innovations are currently under consideration.

The official “Preprint” of the change proposals for the 2017 edition of the NESC was released on Sept 1, 2014, followed by an 8-month open commentary period, which ended on May 1, 2015. The review is now closed, and we have moved on to the next step in the process.

How does the NESC steadily evolve to improve protection for utility linemen, field superintendents and the public?

Changes Under Consideration for the 2017 NESC

Introduced 100 years ago and in use continuously since then, the NESC lays out ground rules for basic provisions deemed necessary for employee and public safety during installation, operation and maintenance of electric supply and communication lines and their associated equipment. The code applies from inception or receipt from another entity of electric energy or communications to the “service point,” where the transfer to a premises wiring system takes place. Covering ttelephone, cable TV and railroad signal systems at both public and private utilities, the NESC outlines basic safety provisions mostly for outdoor delivery lines and associated hardware and equipment.

For example, in Section 9 of the NESC, “Grounding Methods,” an exception has been proposed for grounding of messenger wires in areas where the installation of appropriate structures is limited by terrain such as river crossings and mountains. Presently, the code requires messenger wires to be grounded four times along each mile of line, at a maximum of 0.25 mile. The exception would be used based on the neutral being of sufficient current capacity for the application; all available structures should be grounded, however. A similar change proposal that is under consideration would allow less than four grounds per mile for installation in duct, where removal of the protective jacket of a cable would be required.

Some of the other proposed changes for the 2017 code address:

  • definitions for communication equipment, electric supply equipment and structure conflict;
  • clearance rules pertaining to the communication space above supply space;
  • elimination of an exemption that is in place for structures and supported facilities that do not exceed 60 feet in height from rules regarding extreme wind and extreme ice with concurrent wind loading, and
  • harmonization on the NESC’s work rules with Occupational Safety & Health Administration (OSHA) CFR 1910.269 and 1926 Subpart V final rulings.

The change proposals have already been discussed and voted on by the NESC’s technical subcomittee members from around the United States, and utility linemen and field superintendents with experience in the real-world field of implementation, as well as any other individual, have helped influence the future of the code by submitting their suggestions during the open commentary period. They have played a great part in producing the next, best edition of the NESC.

A Methodical Process of Evolution

The secretariat of the NESC since 1972 has been IEEE. As the standards and collaborative solutions arm of IEEE, the IEEE Standards Association (IEEE-SA) oversees a structured, five-year process of refinement of the NESC that will lead to the scheduled 1 August 2016 publication of the 2017 code:

  • Any interested person, organization, NESC subcommittee or member of the NESC Committee or its subcommittees may prepare and electronically submit a change proposal for the next edition of the code.
  • All proposals are considered by NESC subcommittees, which then endorse the proposals, propose revisions or additions to them, refer the proposals to technical working groups for additional consideration, ask for coordination with other subcommittees and/or recommend rejection of the proposals.
  • The Preprint of the proposed change proposals is published and made publicly available for an eight-month period of open commentary.
  • After the commentary period closes, the proposed revisions and their associated comments are reviewed by the cognizant NESC technical subcommittees. The subcommittees will make final recommendations that are incorporated into the NESC 2017 draft, which is then submitted to the NESC Main Committee for final letter ballot in January 2016 and subsequent approval by the American National Standards Institute (ANSI).
  • A draft of the next edition of the NESC is prepared based on the subcommittee reports, and then it is distributed to the NESC Main Committee for approval by a six-week letter ballot and the American National Standards Institute (ANSI) Board of Standards Review for concurrent 60-day public review.

Contributing to the Safety of Utility Workers and the Public

Today, the NESC ranks as one of the most widely adopted safety codes. Though it is not a design specification or instruction manual itself, the NESC and its safety guidelines inform utility work in a variety of ways.

One of the primary ways that the NESC helps keep utility workers and the public safe is through its adoption in whole or part by state legislatures and public service commissions (PSCs). California, for example, utilizes its own state safety code, but it reviews its requirements as new editions of the NESC are released every five years. There are other U.S. states that adopt only the NESC’s construction and maintenance rules; others, though they might not directly adopt a safety code for utilities, refer to the current edition of the NESC when issues arise related to the code’s scope. Furthermore, the Caribbean islands, U.S. territories and U.S. military bases around the world use the NESC, as do U.S. Agency for International Development (USAID) programs that bring electricity to nations in cooperation with the U.S. Department of Agriculture Rural Utilities Service. In all, there are about 100 countries globally that rely on the NESC in some way—though, in some cases, the code is modified because of local climate anomalies.

In addition, the holistic safety programs that have been adopted by individual utilities—encompassing safety manuals, “tailboard discussions,” all-hands safety meetings, spot checks to ensure regulations are being followed, apprentice programs, etc.—often are informed by the NESC.

Initially introduced in August 1914, the NESC has remained a relevant, essential resource for utility linemen, field superintendents and the public even 100 years after its introduction because of a broadly shared commitment to keep it up to date through a proven process of constant improvement. As soon as one edition of the code is released, work on the next edition commences. The result is that the NESC’s contribution to the culture of safety that has taken shape around utility work is profound—lives have been saved. Everyone who has contributed to the NESC’s ongoing refinement over the last 100 years has had a hand in that success.

Jim Tomaseski is a member of IEEE, vice chair of the NESC Main Committee and Corporate Director of Safety – PAR Electrical Contractors.

Voice your opinion!

To join the conversation, and become an exclusive member of T&D World, create an account today!