100 — Definitions

Article 100 — Definitions – Scope and Part III, Hazardous (Classified) Locations

Reason for Change:

The phrase, “Definitions are also found in XXX.2 sections of other articles” was added and the Scope of Article 100 is modified to include new Part III for “Hazardous (Classified) Locations.”

Article 100: Definitions

Scope. This article contains only those definitions essential to the application of this Code. It is not intended to include commonly defined general terms or commonly defined technical terms from related codes and standards. In general, only those terms that are used in two or more articles are defined in Article 100. Other definitions are included in the article in which they are used but may be referenced in Article 100. Definitions are also found in XXX.2 sections of other articles.

Part I of this article contains definitions intended to apply wherever the terms are used throughout this Code. Part II contains definitions applicable to installations and equipment operating at over 1000 volts, nominal. Part III contains definitions applicable to Hazardous (Classified) Locations.

Article 100 — Definitions – Accessible (as applied to equipment)

Reason for Change:

The definition of Accessible (as applied to equipment) was revised for clarity and usability.

Accessible (as applied to equipment). Admitting close approach; not guarded by locked doors, elevation, or other effective means. Capable of being reached for operation, renewal, and inspection. (CMP-1)

Article 100 — Definitions – Supply-Side Bonding Jumper

Reason for Change:

The definition of a Supply-Side Bonding Jumper was relocated from 250.2 to Article 100.

Bonding Jumper, Supply-Side. A conductor installed on the supply side of a service or within a service equipment enclosure(s), or for a separately derived system, that ensures the required electrical conductivity between metal parts required to be electrically connected. (CMP-5)

Article 100 — Definitions – Dormitory Unit

Reason for Change:

A new definition for a “Dormitory Unit” was introduced at Article 100.

Dormitory Unit. A building or a space in a building in which group sleeping accommodations are provided for more than 16 persons who are not members of the same family in one room, or a series of closely associated rooms, under joint occupancy and single management, with or without meals, but without individual cooking facilities. (CMP 2)

Article 100 — Definitions – Equipotential Plane

Reason for Change:

The definition for “Equipotential Plane was relocated from 682.2 to Article 100.

Equipotential Plane. An area where wire mesh or other conductive elements are on, embedded in, or placed under the walk surface within 75 mm (3 in.), bonded to all metal structures and fixed nonelectrical equipment that may become energized, and connected to the electrical grounding system to prevent a difference in voltage from developing within the plane. Accessible conductive parts bonded together to reduce voltage gradients in a designated area. (CMP-17)

Article 100 — Definitions – Fault Current and Fault Current, Available (Available Fault Current)

Reason for Change:

Two new definitions for “Fault Current” and “Fault Current, Available (Available Fault Current)” were added to Article 100. A new Informational- Note Figure 100.1 was also added.

Fault Current. The current delivered at a point on the system during a short-circuit condition. (CMP-10)

Fault Current, Available (Available Fault Current). The largest amount of current capable of being delivered at a point on the system during a short-circuit condition. (CMP-10)
Informational Note: A short-circuit can occur during abnormal conditions such as a fault between circuit conductors or a ground fault. See Informational Note Figure 100.1.
Figure Informational Note Figure 100.1 Available Fault Current.
(see illustration above and NEC Code text for figure)

Article 100 — Definitions – Free Air (as applied to conductors)

Reason for Change:

A new definition for “Free Air (as applied to conductors)” was added to Article 100.

Free Air (as applied to conductors). Open or ventilated environment that allows for heat dissipation and air flow around an installed conductor. (CMP-6)

Article 100 — Definitions – Grounded Conductor

Reason for Change:

A new Informational note was added to the definition of a “Grounded Conductor.” The new informational note is intended to clarify that an equipment grounding conductor is not subject to the identification and connection rules of a grounded conductor.

Grounded Conductor. A system or circuit conductor that is intentionally grounded. (CMP-5)
Informational Note: Although an equipment grounding conductor is grounded, it is not considered a grounded conductor.

Article 100 — Definitions – Habitable Room

Reason for Change:

A new definition for “Habitable Room” was added to Article 100.

Habitable Room. A room in a building for living, sleeping, eating, or cooking, but excluding bathrooms, toilet rooms, closets, hallways, storage or utility spaces, and similar areas. (CMP-2)

Article 100 — Definitions – Island Mode

Reason for Change:

A new definition for “Island Mode” primarily related to microgrid systems and stand-alone systems was added to Article 100.

Island Mode. The operational mode for standalone power production equipment or an isolated microgrid, or for a multimode inverter or an interconnected microgrid that is disconnected from an electric power production and distribution network or other primary power source. (CMP-4)
Informational Note: Isolated microgrids are distinguished from interconnected microgrids, which are addressed in Article 705.

Article 100 — Definitions – Labeled

Reason for Change:

New Informational Note added explaining that even though a section of the NEC may require a product to be labeled, it is common practice to have the label, symbol, or other identifying mark applied to the smallest unit container in which the product is packaged.

Labeled. Equipment or materials to which has been attached a label, symbol, or other identifying mark of an organization that is acceptable to the authority having jurisdiction and concerned with product evaluation, that maintains periodic inspection of production of labeled equipment or materials, and by whose labeling the manufacturer indicates compliance with appropriate standards or performance in a specified manner. (CMP-1)
Informational Note: If a listed product is of such a size, shape, material, or surface texture that it is not possible to apply legibly the complete label to the product, the complete label may appear on the smallest unit container in which the product is packaged.

Article 100 — Definitions – Reconditioned

Reason for Change:

A new definition for “Reconditioned” was added to Article 100 and an informational note added to indicate that the term reconditioned is frequently referred to as rebuilt, refurbished, or remanufactured.

Reconditioned. Electromechanical systems, equipment, apparatus, or components that are restored to operating conditions. This process differs from normal servicing of equipment that remains within a facility, or replacement of listed equipment on a one-to-one basis. (CMP-10)
Informational Note: The term reconditioned is frequently referred to as rebuilt, refurbished, or remanufactured.