Clarifying the NESC/NEC boundary

The demarcation between National Electrical Safety Code (NESC) and National Electrical Code (NEC) sounds simple, but it can be quite complex.

01/12/2012


Electricity can be as dangerous as it is vital. One of the chief resources that protect electrical professionals and the public are standards that promote safe practices. Utilities employees, who provide electrical services up to the premise edge, follow the National Electrical Safety Code (NESC). Electricians working with in-premises wiring and utilization equipment use the National Electrical Code (NEC). This demarcation sounds simple, but it is actually a complex issue. Under many scenarios, the line between on-premise and off-premise is often misunderstood. Using the correct code is important for safe operation that protects the employee and the public.

The need to align codes

While electricians and utilities workers both deal with electricity, they operate in different environments with distinct safety requirements. Electricians tend to work on equipment that is “dead” (unpowered), to enhance safety. Utilities workers commonly work with live current to maintain power distribution. Electricians also tend to work with the lower voltages found in homes and businesses, while utilities workers commonly work with the high voltages found in power lines.

These differences can cause problems when the two codes overlap in the field. For example, the NEC applies to lighting circuits. That sounds clear, but what about parking lot security lighting that also illuminates a street? The NESC covers street and area lighting. Street lights are commonly managed by a municipality. Ownership of such borderline areas is often controlled by the Public Utilities Commission (PUC), but even this might not be a solution. The PUC is a state entity, so its rules vary by location. Some companies and utilities span multiple states, which creates a challenge in training employees in the use of the proper code.

The question of who is responsible for what can pose important safety questions. For example, both the NESC and NFPA 70E include tables that provide the required rating of flame-resistant (FR) clothing for working with power up to 1,000 Vac. But the tables are not the same. The primary difference is that the NFPA 70E table values are based on calculations, while the NESC table values are a combination of arc energy levels from calculations and results from actual test results performed in a utility test lab.

There are generally two scenarios for electric arcs: open air arcs and the arc-in-a-box. Both the NESC and NFPA 70E contain tables that have arc energy exposures simulating the arc-in-the-box (new in the 2012 edition of the NESC: Table 410-1). The other two tables in the NESC (410-2 and 410-3) contain arc energy levels that are unique to open air arcs.

Enhancing safety

As the safety, training, and on-the-job needs for clarification resulting from the overlap between the NESC and NEC grew, the IEEE, NESC, and the NFPA realized that there could be an industry benefit by working together. The solution was a joint task force, created to clarify when each code should apply.

The group began by educating the organizations about each others’ codes, and discussing how to change areas of purpose and scope. Some of the results can be seen in the 2012 Edition of the NESC standard, which was introduced on Aug. 1, 2011. That code now includes detailed language that specifies what the code covers for areas such as generation, transmission, and distribution of electricity. A separate section describes what the NESC does not cover, such as installations in ships, rolling equipment, aircraft, and more.

Moving forward

While the boundary between the NESC and NEC might not be completely understood, the addition to the current edition of the NESC is an important first step to clarifying the NESC’s scope. The task force will continue to meet and introduce code changes that protect the public, electrical professionals, equipment, and property.

Hyland is the chair of the National Electrical Safety Code and senior vice president of engineering services with the American Public Power Assn. Tomaseski is the director of the International Brotherhood of Electrical Workers safety and health department, and vice chair of the NESC.


Distinguishing NESC and NEC

 

The National Electrical Safety Code (NESC) is a code published by the Institute of Electrical and Electronics Engineers (IEEE). It has defined safe practices for installing, operating, and maintaining electric supply and communications lines, and associated equipment, for more than 90 years. Every 5 years, the NESC is updated with critical revisions concerning new techniques and technologies. Utilities workers use the NESC to safeguard themselves and the public while working under specified conditions.

The National Electrical Code (NEC), or NFPA 70, code is published every 3 years by the National Fire Prevention Association (NFPA). The NEC defines the requirements for safe electrical installations. State and local laws commonly require electricians to comply with the NEC.

Both codes will continue to play critical roles in addressing evolving electrical safety challenges.



No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2015 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
Hannover Messe 2016: Taking hold of the future - Partner Country status spotlights U.S. manufacturing; Honoring manufacturing excellence: The 2015 Product of the Year Winners
Inside IIoT: How technology, strategy can improve your operation; Dry media or web scrubber?; Six steps to design a PM program
World-class manufacturing: A recipe for success: Finding the right mix for a salad dressing line; 2015 Salary Survey: Manufacturing slump dims enthusiasm
Getting to the bottom of subsea repairs: Older pipelines need more attention, and operators need a repair strategy; OTC preview; Offshore production difficult - and crucial
Digital oilfields: Integrated HMI/SCADA systems enable smarter data acquisition; Real-world impact of simulation; Electric actuator technology prospers in production fields
Special report: U.S. natural gas; LNG transport technologies evolve to meet market demand; Understanding new methane regulations; Predictive maintenance for gas pipeline compressors
Warehouse winter comfort: The HTHV solution; Cooling with natural gas; Plastics industry booming
Managing automation upgrades, retrofits; Making technical, business sense; Ensuring network cyber security
Designing generator systems; Using online commissioning tools; Selective coordination best practices

Annual Salary Survey

Before the calendar turned, 2016 already had the makings of a pivotal year for manufacturing, and for the world.

There were the big events for the year, including the United States as Partner Country at Hannover Messe in April and the 2016 International Manufacturing Technology Show in Chicago in September. There's also the matter of the U.S. presidential elections in November, which promise to shape policy in manufacturing for years to come.

But the year started with global economic turmoil, as a slowdown in Chinese manufacturing triggered a worldwide stock hiccup that sent values plummeting. The continued plunge in world oil prices has resulted in a slowdown in exploration and, by extension, the manufacture of exploration equipment.

Read more: 2015 Salary Survey

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
This article collection contains several articles on the vital role that compressed air plays in manufacturing plants.
This article collection contains several articles on the Industrial Internet of Things (IIoT) and how it is transforming manufacturing.
click me