Article 100 definitions

Branch Circuit, Multiwire

A branch circuit that consists of two or more ungrounded conductors that have a voltage between them, and a grounded conductor that has equal voltage between it and each ungrounded conductor of the circuit and that is connected to the neutral or grounded conductor of the system.

Branch Circuit, Appliance

A branch circuit that supplies energy to one or more outlets to which appliances are to be connected and that has no permanently connected luminaires that are not a part of an appliance.

Branch Circuit, Individual

A branch circuit that supplies only one utilization equipment.

Branch Circuit, General-Purpose

A branch circuit that supplies two or more receptacles or outlets for lighting and appliances.

Garage

A building or portion of a building in which one or more self-propelled vehicles can be kept for use, sale, storage, rental, repair, or demonstration purposes.

Dwelling, One Family

A building that consists solely of one dwelling unit.

Dwelling, Two Family

A building that consists solely of two dwelling units.

Dwelling, Multi-Family

A building that contains three or more dwelling units.

Hermetic Refrigerant Motor-Compressor

A combination consisting of a compressor and motor, both of which are enclosed in the same housing, with no external shaft or shaft seals, with the motor operating in the refrigerant.

Adjustable Speed Drive System

A combination of an adjustable speed drive, its associated motor(s), and auxiliary equipment.

Grounding Electrode

A conducting object through which a direct connection to earth is established.

Conductor, Insulated

A conductor encased within material of composition and thickness that is recognized by this code as electrical insulation.

Conductor, Covered

A conductor encased within material of composition or thickness that is not recognized by this code as electrical insulation.

Conductor, Bare

A conductor having no covering or electrical insulation whatsoever.

Grounding Electrode Conductor

A conductor used to connect the system grounded conductor or the equipment to a grounding electrode or to a point on the grounding electrode system.

Counter-Mounted Cooking Unit

A cooking appliance designed for mounting in or on a counter and consisting of one or more heating elements, internal wiring, and built in or mountable controls.

Circuit Breaker

A device designed to open and close a circuit by nonautomatic means and to open the circuit automatically on a predetermined overcurrent without damage to itself when properly applied within its rating.

Ground-Fault Circuit Interrupter (GFCI)

A device intended for the protection of personnel that functions to de-energize a circuit or portion thereof within an established period of time when a current to ground exceeds the values established for a Class A device.

Arc-Fault Circuit Interrupter (AFCI)

A device intended to provide protection from the effects of arc faults by reorganizing characteristics unique to arcing and by functioning to de-energize the circuit when an arc fault is detected.

Controller

A device or group of devices that serves to govern, in some predetermined manner, the electric power delivered to the apparatus to which it is connected.

Connector, Pressure (solderless)

A device that establishes a connection between two or more conductors or between one or more conductors and a terminal by means of mechanical pressure and without the use of solder.

Intersystem Bonding Termination

A device that provides a means for connecting intersystem bonding conductors for communications systems to the grounding electrode system.

Attachment Plug (Plug Cap)(Plug)

A device that, by insertion in a receptacle, establishes a connection between the conductors of the attached flexible cord and the conductors connected permanently to the receptacle.

Disconnecting Means

A device, or group of devices, or other means by which the conductors of a circuit can be disconnected from their source of supply.

Electric Sign

A fixed, stationary, or portable selfcontained, electrically illuminated utilization equipment with words or symbols designed to convey information or attract attention.

Equipment

A general term, including fittings, devices, appliances, luminaires, apparatus, machinery, and the like used as a part of, or in connection with, an electrical installation.

Continuous Load

A load where the maximum current is expected to continue for 3 hours or more.

Clothes Closet

A nonhabitable room or space intended primarily for storage of garments or apparel.

Bonding Conductor or Jumper

A reliable conductor to ensure the required electrical conductivity between metal parts required to be electrically connected.

Conduit Body

A separate portion of a conduit or tubing system that provides access through a removable cover to the interior of the system at a junction of two or more sections of the system or at a terminal point of the system. Boxes such as FS and FD are larger cast or sheet metal boxes are NOT classified as conduit boxes.

Cable Routing Assembly

A single channel or connected multiple channels, as well as associated fittings, forming a structural system that is used to support and route communications wires and cables, optical fiber cables, data cables associated with information technology and communications equipment, Class 2 and Class 3 cables, and power limited fire alarm cables.

Dwelling Unit

A single unit, providing complete and independent living facilities for one or more persons, including permanent provisions for living, sleeping, cooking and sanitation.

Festoon Lighting

A string of outdoor lights that is suspended between two points.

Building

A structure that stands alone or that is cut off from adjoining structures by fire walls with all openings therein protected by approved fire doors.

Hybrid System

A system comprised of multiple power sources. These power sources could include photovoltaic, wind, micro-hydro generators, engine-driven generators, and others, but do not include electric power production and distribution network systems. Energy storage systems such as batteries, flywheels, or superconducting magnetic storage equipment do not constitute a power source for the purpose of this definition. The energy regenerated by an overhauling (descending) elevator does not constitute a power source for the purpose of this definition.

Ground-Fault Protection of Equipment

A system intended to proved protection of equipment from damaging line-to-ground fault currents by operating to cause a disconnecting means to open all ungrounded conductors of the faulted circuit. This protection is provided at current levels less than those required to protect conductors from damage through the operation of a supply circuit overcurrent device.

Grounded Conductor

A system or circuit conductor that is intentionally grounded.

Device

A unit of an electrical system, other than a conductor, that carries or controls electric energy as its principal function.

Approved

Acceptable tot he authority having jurisdiction.

Accessible (as applied to equipment)

Admitting close approach; not guarded by locked doors, elevation, or other effective means

Feeder

All circuit conductors between the service equipment, the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device.

Fitting

An accessory such as a lockout, bushing, or other part of a wiring system that is intended primarily to perform a mechanical rather than an electrical function.

Guest Room

An accommodation combining living, sleeping, sanitary, and storage facilities within a compartment.

Guest Suite

An accommodation with two or more contiguous rooms comprising a compartment, with or without doors between such rooms, that provides living, sleeping, sanitary, and storage facilities.

Bathroom

An area including a basic with one or more of the following: a toilet, a urinal, a tub, a shower, a bidet, or similar plumbing fixtures.

Industrial Control Panel

An assembly of two or more components consisting of one of the following: (1)power circuit components only, such as motor controllers, overload relays, fused disconnect switches, and circuit breakers; (2) control circuit components only, such as push buttons, pilot lights, selector switches, timers, switches, and control relays; (3) a combination of power and control circuit components. These components, with associated wiring and terminals, are mounted on, or contained within, an enclosure or mounted on the subpanel. The industrial control panel does not include the controlled equipment.

Interactive System

An electric power production system that is operating in parallel with and capable of delivering energy to an electric primary source supply system.

Ground-Fault Current Path

An electrically conductive path from the point of ground fault on a wiring system through normally non-current-carrying conductors, equipment, or the earth to the electrical supply source.

Communications Raceway

An enclosed channel of non-metallic materials designed expressly for the holding of communications wires and cables, typically communications wires and cables and optical fiber and data (class 2 and class 3) in plenum, rise, and general-purpose applications.

Cutout Box

An enclosure designed for surface mounting that has swinging doors or covers secured directly to and telescoping with the walls of the box proper.

Handhole Enclosure

An enclosure for use in underground systems, provided with an open or closed bottom, and sized to allow personnel to reach into, but not enter, for the purpose of installing, operating, or maintaining equipment or wiring or both.

Cabinet

An enclosure that is designed for either surface mounting or flush mounting and is provided with a frame, mat, or trim in which a swinging door or doors are or can be hung.

Effective Ground-Fault Current Path

An intentionally constructed, low-impedance electrically conductive path designed and intended to carry current under ground-fault conditions from the point of a ground fault ona wiring system to the electrical supply source and that facilitates the operation of the overcurrent protective device or ground-fault detectors.

Authority Having Jurisdiction (AH)

An organization, office, or individual responsible for enforcing the requirements of a code or standard, or for approving equipment, materials, an installation, or procedure.

Electronically Actuated Fuse

An overcurrent protective device that generally consists of a control module that provides current-sensing, electronically derived time-current characteristics, energy to initiate tripping, and an interrupting module that interrupts current when an overcurrent occurs. Such fuses may or may not operate in a current-limiting fashion, depending on the type of control selected.

Ground Fault

An unintentional, electrically conductive connection between an ungrounded conductor of an electrical circuit and the normally non-current-carrying conductors, metallic enclosures, metallic raceways, metallic equipment, or earth.

Hoistway

Any shaftway, hatchway, well hole, or other vertical opening or space in which an elevator or dumbwaiter is designed to operate.

Exposed (as applied to live parts)

Capable of being inadvertently touched or approached nearer than a safe distance by a person.

Externally Operable

Capable of being operated without exposing the operator to contact with live parts.

Accessible, Readily (Readily Accessible)

Capable of being reached quickly for operation, renewal, or inspections without requiring those to whom ready access is requisite to actions such as to use tools, to climb over or remove obstacles, or to resort to portable ladders, and so forth.

Accessible (as applied to wiring methods)

Capable of being removed or exposed without damaging the building structure or finish or not permanently closed in by the structure or finish of the building

Copper-Clad Aluminum Conductors

Conductors drawn from a copper-clad aluminum rod, with the copper metallurgically bonded to an aluminum core, where the copper forms a minimum of 10 percent of the cross-sectional area of a solid conductor or each strand of a stranded conductor.

Grounded (Grounding)

Connected (connecting) to ground or to a conductive body that extends the ground connection.

Bonded (Bonding)

Connected to establish continuity and conductivity.

Grounded, Solidly

Connected to ground without inserting any resistor or impedance device.

Dusttight

Constructed so that dust will not enter the enclosing case under specified test conditions.

Guarded

Covered, shielded, fenced, enclosed, or otherwise protected by means of suitable covers, casings, barriers, rails, screens, mats, or platforms to remove the likelihood of approach or contact by persons or objects to a point of danger.

Energized

Electrically connected to, or is, a source of voltage.

Explosion proof Equipment

Equipment enclosed in a case that is capable of withstanding an explosion of a specified gas or vapor that may occur within it and of preventing the ignition of a specified gas or vapor surrounding the enclosure by sparks, flashes, or explosion of the gas or vapor within, and that operates at such an external temperature that a surrounding flammable atmosphere will not be ignited thereby.

Charge Controller

Equipment that controls DC voltage or DC current, or both, and that is used to charge a battery, or other energy storage device.

Battery System

Interconnected binary subsystems consisting of one or more storage batteries and battery chargers, and can include inverters, converters, and associated electrical equipment.

Duty, Periodic

Intermittent operation in which the load conditions are regularly recurrent.

Coordination (Selective)

Localization of an overcurrent condition to restrict outages to the circuit or equipment affected, accomplished by the selection and installation of overcurrent protective devices and their ratings or settings for the full range of available overcurrents, from overload to the maximum available fault current, and for the full range of overcurrent protective device opening times associated with those overcurrents.

Isolated (as applied to location)

Not readily accessible to persons unless special means for access are used.

Exposed (as applied to wiring methods)

On or attached to the surface or behind panels designed to allow access.

Duty, Short-Time

Operation at a substantially constant load for a short and definite, specified time.

Duty, Continuous

Operation at a substantially constant load for an indefinitely long time.

Duty, Varying

Operation at loads, and for intervals of time, both of which may be subject to wide variations.

Duty, Intermittent

Operation for alternate intervals of 1 load and no load; or two load and rest; or 3 load, no load, and rest.

Automatic

Performing a function without the necessity of human intervention.

Adjustable Speed Drive

Power conversion equipment that provides a means of adjusting the speed of an electric motor.

Electric Power Production and Distribution Network

Power production, distribution, and utilization equipment and facilities, such as electric utility systems that deliver electric power to the connected loads, that are external to and not controlled by an interactive system.

Identified (as applied to equipment)

Recognizable as suitable for the specific purpose, function, use, environment, application, and so forth, where described in a particular code requirement.

Concealed

Rendered inaccessible by the structure or finish of the building.

Enclosed

Surrounded by a case, housing, fence, or wall that prevents person from accidentally contacting energized parts.

Electric-Discharge Lighting

Systems of illumination utilizing fluorescent lamps, high-intensity discharge (HID) lamps, or neon tubing.

Enclosure

The case or housing of apparatus, or the fence or walls surrounding an installation to prevent personnel from accidentally contacting energized parts or to protect the equipment from physical damage.

Branch Circuit

The circuit conductors between the final overcurrent device protecting the circuit and the other(s).

Control Circuit

The circuit of a control apparatus or system that carries the electric signals directing the performance of the controller but does not carry the main power current.

Grounding Conductor, Equipment (EGC)

The conductive path(s) that provides a ground-fault current path and connects normally non-current-carrying metal parts of equipment together and to the system grounded conductor or to the grounding electrode conductor, or both. More info in Section 250.118

Bonding Jumper, Main

The connection between the grounded circuit conductor and the equipment grounding conductor at service.

Bonding Jumper, System

The connection between the grounded circuit conductor and the supply-side bonding jumper, or the equipment grounding conductor, or both, at a separately derived system.

Bonding Jumper, Equipment

The connection between two or more portions of the equipment grounding conductor.

Ground

The earth

Communications Equipment

The electronic equipment that performs the telecommunications operations for the transmission of audio, video, and data, and includes power equipment, technical support equipment, and conductors dedicated solely to the operation of the equipment.

Interrupting Rating

The highest current at rated voltage that a device is identified to interrupt under standard test conditions.

Ampacity

The maximum current, in amperes, that a conductor can carry continuously under the conditions or use without exceeding its temperature rating.

Demand Factor

The ratio of maximum demand of a system, or part of a system, to the total connected load of a system or part of the system under consideration.

Appliance

Utilization equipment, generally other than industrial, that is normally built in standardized sizes or types and is installed or connected as a unit to perform one or more functions such as clothes washing, air-conditioning, food mixing, deep frying and so forth.

Dead Front

Without live parts exposed to a person on the operating side of the equipment.