NEC Article 100 covers the basic definitions used throughout the code to ensure clear understanding and consistent application. Terms explained in the article appear throughout the blog. Below are the basic definitions from Section 100 of the NEC, highlighted for clarity.
Basic definitions from the first part (general):
Accessible (as applied to equipment): Equipment that is accessible for operation, refurbishment, or inspection without removing building materials or structures.
Accessible (as applied to wiring methods): Can be removed or exposed without damaging the building structure or finish or not permanently sealed by the building structure or finish. Indicates if anything needs to be changed in the building to access the wiring.
Easily accessible (easily accessible): Equipment that can be quickly accessed without obstacles or stairs. This term mostly refers to how quickly you can access equipment.
Capacity: The maximum current, in amperes, that a conductor can carry continuously without exceeding its temperature.
device: Use non-industrial equipment of standard sizes or types that performs functions such as cooking or air conditioning.
The competent authority (AHJ): The organization or individual responsible for enforcing rules or approving materials and formulations.
Bonded (bonding): Connecting metal parts to establish electrical continuity and conductivity.
Branch Department: Connectors between the final overcurrent device and the outlet(s).
Circuit breakers: A device designed to open and close a circuit by non-automatic means and to open the circuit automatically when an overcurrent occurs, without damaging the device itself.
Conductor (bare, covered, insulated): A material that allows electrical current to flow, and is classified as bare (no covering), covered (covered with a non-insulating material), or insulated.
Continuous load: Load where the maximum current is expected to last for 3 hours or more.
Ground (grounding): A conductive connection to ground or to a conductive object that serves as an alternative to ground.
Grounding conductor: A conductor that connects electrical equipment or the grounded portion of a wiring system to a grounding electrode, usually a metal rod or plate buried in the ground, to ensure the safe dissipation of electrical currents.
Ground Fault Circuit Interrupter (GFCI): A device intended to protect personnel by de-energizing a circuit when the current to ground exceeds a specified threshold (usually 6 mA).
Overcurrent: A current exceeding the equipment’s rated current or conductor ampacity, including overloads and short circuits.
Feeder: All conductors between service equipment and the final overcurrent device of the branch circuit.
Separation methods: A device or group of devices by which a circuit can be disconnected from its power source.
Location, Rutba: Places protected from the weather but subject to moderate humidity, such as under awnings or in some basements.
Dry location: Sites are not typically exposed to moisture or wetness but are temporarily exposed to moisture, such as during building construction.
Wet location: Places prone to becoming saturated with water or other liquids, such as vehicle wash areas or outdoor facilities.
Photovoltaic solar system: A system of components and subsystems that convert solar energy into electrical energy suitable for use in a building or connection to a load.
Basic definitions from Part II (over 600 V, nominal):
Valves: Overcurrent protection device with a fusible part that opens the circuit and is heated and disconnected by overcurrent.
Switch device: A device designed to close, open, or both one or more electrical circuits.
