NESC

National Electrical Safety Code

Published by IEEE, the National Electrical Safety Code (NESC®) is a standard – adopted on the state level by state OSHA organizations– that sets the ground rules for practical safeguarding of workers during the installation, operation, or maintenance of electric supply and communication lines and associated equipment. This standard covers systems and equipment operated by utilities, or similar systems and equipment of an industrial establishment or complex under the control of qualified persons.

Adoption of the NESC varies by state. In areas where the code has been adopted, it is enforceable as law. The most up-to-date source for information on NESC adoption by state is available directly from the IEEE website:

Click to access pssurvey.pdf

The NESC is revised every five years.

  • 3Q through 4Q 2010 – NESC subcommittees and workgroups review proposed comments.
  • 15 January 2011 – Proposed revision submitted to NESC Committee for letter ballot and to ANSI for concurrent public review.
  • 15 May 2011 – Approved revisions submitted to NESC Committee for letter ballot and to ANSI for recognition as an ANSI standard.
  • August 2011 – Publication of the 2012 edition of the NESC.

Most changes to the NESC 2012 will occur in Part 4: Rules for the Operation of Electric Supply and Communications Lines and Equipment, with a few significant issues identified:

Arc Hazard:

  • The 2012 edition will specifically include details regarding low voltage, long duration arc exposures (<1000 volts), including a possible new method of calculating these plasma arcs (vs. radiant heat arcs).  The new standard might require the employer to conduct a hazard assessment for low voltages (50-1000 volts).  The 2012 edition will provide a table similar to the existing tables in the 2007 edition, with additional clarification.

Minimum Approach Distances (MAD).

  • Minimum Approach distances will be assessed (guide for maintenance methods on energized power lines).  A possible error in the original calculation of the MAD will be assessed in the 2012 edition of the NESC.

Other possible issues to be addressed:

  • Discussion of layering (non-FR base layers with FR outer layers)
  • The line of demarcation between NFPA 70E and the NESC will possibly be discussed.