Friday, 01 December 2006 19:52

NESC-2007 Update

Written by 

The 2007 edition of the National Electrical Safety Code may pose significant work rule changes for electric utilities. The updated code, which is detailed in the NESC-2007 handbook, covers the following areas.

Effective January 1, 2009, the updated code requires each employer to perform an arc hazard assessment for employees who work on or near energized parts or equipment.
If the assessment determines a potential employee exposure greater than 2 cal/cm2, the employer will be required to provide clothing/clothing systems that have an effective arc rating not less than the anticipated exposure.
The arc rating called the Arc Thermal Performance Value (ATPV) expressed in calories per square centimeter represents the maximum capability for arc flash protection of arc flash clothing, which may include clothing systems. Employers are required to determine the ATPV value and perform an arc hazard analysis when employee exposure is 1 kV or greater so an effective clothing or clothing system can be determined. Employees who have exposure to secondary systems less than 1 kV (meter technicians, etc.) may wear clothing or clothing systems with a minimum effective arc rating of 4 cal/cm2 to limit exposure. The code does recognize that energy levels can be excessive with secondary systems so it requires utility safe work rules and engineering controls to be utilized to reduce the levels. This may be accomplished by either performing an arc hazard assessment or by using the tables in the code.
Clothing systems, according to the code, include multiple layers with the outer layer being of flame-resistant materials. This requirement poses a significant change for electric utilities that have designed clothing or clothing systems so they would not contribute to the extent of the burn. This takes a more proactive role in the design of clothing and clothing systems and ensures that employers provide clothing to protect employees from the hazards of electric arcs.

The code updates requirements for safety signs and tags to comply with the provisions of ANSI Z535.1-2006 through ANSI Z535.5-2006. The 2006 ANSI standards address three types of safety messages: grouped safety messages, section safety messages and embedded messages. The grouped safety messages appear with the words "Danger," "Warning," "Caution," and "Notice." Many utilities may already be required to update their signage to comply with the changes in the new ANSI standards.

Changes have been made with regard to qualification of employees who are now required to be qualified prior to operating mechanical equipment. "Qualified" employees must be able to identify electric and communication lines and equipment, know approach distances that must be maintained for safety, understand conditions that could occur if contact with lines and equipment occurs, and understand the safety action plan that must be initiated for employee and public safety if a contact occurs. The code also addresses qualification of employees who do not normally work on or in the vicinity of electric lines or equipment but their work brings them into these areas. These employees may only proceed with their work when authorized by a qualified person. This change aligns the NESC code with OSHA standards.

Changes in underground line operating procedures include boring and directional drilling methods, the use of mechanical equipment, and requirements for hand digging near buried energized cables. Under the new code, existing utility facilities must be exposed prior to performing a boring operation. Additionally, mechanized equipment should not be used to excavate close to buried electric cables and nonconductive handles should be used on hand tools when digging near energized electric cables. This may require buried electric cables to be uncovered by hand digging.

The code update requires insulating cover-up to be rated for phase-to-phase voltage if a determination shows that phase-to-phase exposure may exist. If not, cover-up used may be rated for phase-to-ground voltage exposure. When determining exposure and type of cover-up required, the utility may use work rules, conductor spacing and worker position.

The AC live work minimum approach distances, commonly referred to as MAD, changes slightly for both distribution and transmission voltages in the new code. The changes represent the most up-to-date developments in MAD research and will pose a change from current OSHA regulations.

For 2007, the NESC code changes relative to multiple ground cables connected to the same grounding point. The code states, "All phase connections shall be removed before removing any of the ground connections." An exception to this rule allows grounds to be removed individually from each phase and ground conductor if the application of the rule produces a hazard such as contact of the ground with ungrounded parts.ip

Pam Tompkins, a Certified Safety Professional and Certified Utility Safety Administrator, is President of SET Solutions in Lexington, South Carolina. The company specializes in helping small to medium size electric utilities comply with safety and training requirements. Prior to forming SET in 2000, Tompkins worked in the electric utility industry for over 20 years.

Read 5634 times Last modified on Wednesday, 17 November 2010 18:20
Pam Tompkins, CSP, CUSA, CUSP

SET Solutions, LLC is a full-service safety management consulting firm that takes great pride in custom-tailoring its programs and services to meet the diverse needs of our ever-increasing client base. Programs range from full-service safety management programs to on-the-job program development, to site-specific safety training programs and processes.

More in this category: « Total Success at Dominion

iP Contributing Authors


FREE Subscription to iP Magazine.

We'll send you 6 issues a year at no charge!

Safety Management

Utility safety management is no easy job. Managing personnel, staying current on leg/reg issues, understanding record keeping processes and policy enforcement are only a few of the areas Incident Prevention provides in-depth coverage.

Read Safety Management articles

Personal Protective Equipment

OSHA requires the use of personal protective equipment (PPE) to reduce employee exposure to hazards. FR Clothing, Gloves, Head Protection, Eyewear and Protective Footwear are all PPE.  The  articles listed below discuss their proper use and maintenance. Attend iP Safety Conference & Expo to learn more about the latest PPE products.

Read Personal Protective articles

Tailgate Safety Topics

Tailgate meetings are a critical communication component of any strong utility safety program. Incident Prevention supplies the utility industry with topics for these important meetings. Each article can be printed out for use in the field or emailed to your crews.

Tailgate Safety Topic articles

Worksite Safety

Daily hazards face utility and contractor work crews. Understanding the risks involved, knowing the proper procedures, building a strong culture of open communication and constant awareness will prevent incidents. Our articles on aerial work, underground construction, grounding techniques, high-voltage risks provide utility workers a better understanding of the task at hand.  iP Safety Conferences are another great resource for understanding hazards.

Read Worksite Safety articles

Reader Profiles

Building an effective safety culture requires strong safety leadership.  The iP reader profiles features utility industry safety managers who know what it takes to overcome obstacles that brings their workers home each and every day.

Reader Profile articles

Leadership Development

As our current utility workforce retires, new utility safety leaders are coming onboard all of the time.  Incident Prevention is here to assist in the development of their leadership skills.  Managing people, understanding generational differences, building strong communications skills, establishing accountability are just a few of the subject areas covered in the magazine and at iP Safety Conferences.

Leadership Development articles


Equipment Operations

Safe equipment operations is required on every jobsite.  Utility work requires the use of cranes, derricks, buckets, trenchers, dozers and more.  Learn about the hazards associated with equipment operations in the articles featured below.

 Equipment Operations articles


Grounding systems are designed so they provide the necessary safety functions. Understanding different grounding methods is critical for utility workers.  Incident Preventions relies upon industry experts to author these much needed articles.  For better insight on grounding methods used in the field you may want to attend iP Safety Conference and hear their in-depth presentations.

Read Grounding articles