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2005 NEC Changes Summary Articles 90 through 110

Article 90. Introduction to the 2005 National Electrical Code

Many NEC violations and misunderstandings wouldn't occur if people doing the work simply understood Article 90. For example, many people see NEC requirements as a performance standard. Where in fact, NEC requirements are the bare minimum for safety. This is exactly the stance electrical inspectors, insurance companies, and courts will take when making a decision regarding electrical design or installation.

Article 90 opens by saying the NEC isn't intended as a design specification or instruction manual. The National Electrical Code has one purpose only. That is "the practical safeguarding of persons and property from hazards arising from the use of electricity."

Article 90 then describes the scope and arrangement of the NEC. A person who says, "I cannot find anything in the NEC" is really saying, "I never took the time to review Article 90." The balance of Article 90 provides the reader with information essential to understanding those items you do find in the NEC.

Typically, electrical work requires you to understand the first four Chapters of the NEC, plus have a working knowledge of the Chapter 9 tables. Chapters 5, 6, 7, and 8 make up a large portion of the NEC, but they apply to special situations. They build on, and extend, what you must know in the first four chapters. That knowledge begins with Chapter 1.

Article 90. Introduction - 2005 Change

  • New FPN identifies the type of organizations that may be exempt from the NEC requirements.

Chapter 1 General Requirements

Many people skip Chapter 1 of the NEC because they want something prescriptive-they want something that tells them what to do, cookbook style. But electricity isn't a simple topic you can jump right into. You cannot just follow a few simple steps to get a safe installation. You need a foundation from which you can apply the NEC.

Consider Ohm's law. Would Ohm's Law make sense to you if you did not know what an Ohm is? Similarly, you must become familiar with a few basic rules, concepts, definitions, and requirements that apply to the rest of the NEC, and you must maintain that familiarity as you continue to apply the NEC.

Chapter 1 consists of two main parts. Article 100 provides definitions so people can understand one other when trying to communicate on Code-related matters. Article 110 provides general requirements that you need to know so you can correctly apply the rest of the NEC.

Time spent learning this general material is a great investment. After understanding Chapter 1, some of the NEC requirements that seem confusing to other people-those who do not understand Chapter 1-will become increasingly intuitive to you. That is, they will strike you as being "common sense," because you'll have the foundation from which to understand and apply them. Because you'll understand the principles upon which many NEC requirements in later Chapters are based, you'll read those requirements and not be surprised at all. You'll read them and feel like you already knew them.

Article 100. Definitions

Have you ever had a conversation with someone, only to discover what you said and what he/she heard were completely different? This happens when one or more of the people in a conversation do not understand the definitions of the words being used, and that's why the definitions of key terms are located right up in the front of the NEC, in Article 100.

If we can all agree on important definitions, then we speak the same language and avoid misunderstandings. Because the NEC exists to protect people and property, we can agree it's very important to know the definitions presented in Article 100.

Now, here are a couple of things you may not know about Article 100:

  • Article 100 contains the definitions of many, but not all, of the terms used throughout the NEC. In general, only those terms used in two or more articles are defined in Article 100.
  • Part I of Article 100 contains the definitions of terms used throughout the NEC.
  • Part II of Article 100 contains only terms that apply to systems that operate at over 600V.

How can you possibly learn all these definitions? There seem to be so many. Here are a few tips:

  • Break the task down. Study a few words at time, rather than trying to learn them all at one sitting.
  • Review the graphics in the textbook. These will help you see how a term is applied.
  • Relate them to your work. As you read a word, think of how it applies to the work you're doing. This will provide a natural reinforcement of the learning process.

Article 100. Definitions - 2005 Changes

  • New term "system bonding jumper" added for use with separately derived systems. Previously the term "main bonding jumper" was used to describe the bonding jumper that was installed between the metal case of derived system and one of the separately derived system conductors.

  • The definition "Selective Coordination" was revised to require selective coordination of overcurrent protection devices to be contingent on an overcurrent condition (overload, short circuit or ground fault). In the 2002 NEC, [240.2], selective coordination was based on a fault condition to restrict outages to the equipment affected. Selective coordination is required for:

    • Electrical System Coordination, 240.12
    • Motors, 430.52(C)(3)
    • Elevators, 620.62
    • Fire Pumps, 695.5(C)(2)
    • Emergency Power Systems, 700.28
    • Legally Required Standby Power Systems, 701.18

    The coordination part means the circuit protection scheme confines the interruption to a particular area rather than to the whole system. For example, if someone plugs in a space heater and raises total demand on a 20A circuit to 25A, or if a short circuit or ground fault occurs with selective coordination, the only breaker/fuse that will open is the one protecting just that branch circuit. Without selective coordination, perhaps an entire floor of a building would go dark!

  • The definition of the term "device" was revised to clarify that electronic and electromechanical equipment used to control electric energy is considered a device.

  • The definition of a "dwelling unit" was revised to make it consistent with other NFPA standards, like NFPA 101, Life Safety Code, without impacting the meaning of the term in the NEC.

  • The term "solidly grounded" was contained in 230.95, but it was relocated to Article 100 because it's used in at least eleven articles.

  • A new term "grounding electrode" was added to Article 100 because it's used in twenty-three articles from Article 250 through Article 830.

  • The definition for "grounding electrode conductor" was reworded to clarify that the conductor that connects the building or structure disconnecting means to an electrode, as required by 250.32, is also a grounding electrode conductor.

  • The new term "guest room" was added because it's used in Articles 210, 220, and 240. The definition matches the term found in NFPA 101, Life Safety Code.

  • The new term "guest suite" was added because many lodging facilities contain a "suite" and this term provides guidance to the Code users as to which NEC requirements apply to "guest suites versus guest rooms."

  • New definition "handhole enclosure" was added because the term will be used in the following Code sections:

    • Enclosure not required for splices, 300.15(L)
    • Accessibility of wiring, 314.29
    • Handhole enclosure requirements, 314.30
    • Underground Telecommunications circuits, 800.47
    • Underground CATV circuits, 820.47

  • The definition for "outline lighting" was revised to include low-voltage light emitting diodes.

  • FPN was added to the definition of "qualified person" to give examples of the type of safety training required for a person to be considered qualified.

  • The definition for a "separately derived system" was revised by eliminating the list of electric energy power sources that constitute a separately derived system. Actually the original proposal was to add "fuel cells" to the list. With the list removed, there's no need to keep updating the list of new power sources.

    In addition, the definition was revised to clarify that a separately derived system could be supplied from "other than a source of electric energy." For example a photovoltaic system is a source of electric energy, but a transformer is not a source, it's the equipment that provides the power. Small point, but you know every point counts!

  • The new term "supplementary overcurrent protection device' clarifies the difference between "supplementary overcurrent protective device" and "branch circuit overcurrent protective device."

Article 110. General Requirements

Article 110 sets the stage for how you will implement the rest of the NEC. Consequently, this article contains a few of the most important and yet neglected parts of the NEC. For example:

  • What do you do with unused openings in enclosures?
  • What's the right working clearance for a given installation?
  • How should you terminate conductors?
  • What kinds of warnings, marking, and identification does a given installation require?

It's critical that you master Article 110, and that's exactly what this Illustrated Guide is designed to help you do. As you read this article, remember that doing so helps build your foundation for correctly applying much of the NEC. In fact, the article itself is a foundation for much of the NEC. You may need to read something several times to understand it. The time you take to do that will be well spent. The illustrations will also help. But if you find your mind starting to wander, take a break. What matters is how well you master the material and how safe your work is-not how fast you blazed through a book.

Article 110. General Requirements - 2005 Changes

  • This section requires "electrical equipment to be installed in a neat and workmanlike manner"; but the Code doesn't provide details on what this means. The new FPN give the Code user a reference to an ANSI standard on the subject of installation workmanship.

Author's Comment: The National Electrical Contractors Association (NECA) has created a series of National Electrical Installation Standards (NEISTM) that establish the industry's first quality guidelines for electrical installations. These standards define a benchmark or baseline of quality and workmanship for installing electrical products and systems. They explain what installing electrical products and systems in a "neat and workmanlike manner" means. For more information about these standards, visit

  • The term "meter socket enclosures" was added to the list of equipment on which field marking is required to warn qualified persons of potential electric arc flash hazards. This was added because of a case where a meter installer was injured.
  • Revised text allows the area housing electrical equipment to be controlled by locks of any type, including a combination lock, not just those with a lock and key (as was specified in the 2002 NEC).
  • The requirement that equipment rated 1,200A or more had to be over 6 ft wide before an entrance was required at each end of the working space was removed. The argument for the change was that the size of the arc blast is directly related to the ampere rating of the equipment, and not the physical width of the equipment.
  • The requirements for manholes, which were contained in Part IV of Article 314, were relocated to Article 110, Part V because the code panel felt that they more appropriately relate to this article.

Author's Comment: If you desire more information about any of the above changes, use the link below ...

[ Click here for advanced 2005 product access ]

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