Circuit breaker cont'd - hdbk109220040235

DOE-HDBK-1092-2004

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.

Equipment--A general term including material, fittings, devices, appliances, fixtures, apparatus,

and the like, used as a part of, or in connection with, an electrical installation.

Equipment grounding conductor--See "Grounding conductor, equipment."

Explosion-proof apparatus--Apparatus enclosed in a case that is capable of withstanding an

explosion of a specified gas or vapor which 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 which operates at such an external temperature that it will not ignite a

surrounding flammable atmosphere.

Exposed--(As applied to live parts.) Capable of being inadvertently touched or approached

nearer than a safe distance by a person. It is applied to parts not suitably guarded, isolated, or

insulated. (See "Accessible." and "Concealed.")

Exposed--(As applied to wiring methods.) On or attached to the surface or behind panels

designed to allow access. [See "Accessible. (As applied to wiring methods.)"]

Exposed--(For the purposes of 1910.308(e), Communications systems.) Where the circuit is in

such a position that in case of failure of supports or insulation, contact with another circuit may

result.

Externally operable--Capable of being operated without exposing the operator to contact with

live parts.

Feeder--All circuit conductors between the service equipment, or the generator switchboard of

an isolated plant, and the final branch--circuit overcurrent device.

Fitting--An accessory such as a locknut, bushing, or other part of a wiring system that is

intended primarily to perform a mechanical rather than an electrical function.

Fuse--(Over 600 volts, nominal.) An overcurrent protective device with a circuit opening fusible

part that is heated and severed by the passage of overcurrent through it. A fuse comprises all

the parts that form a unit capable of performing the prescribed functions. It may or may not be

the complete device necessary to connect it into an electrical circuit.

Ground--A conducting connection, whether intentional or accidental, between an electrical

circuit or equipment and the earth, or to some conducting body that serves in place of the earth.

Grounded--Connected to earth or to some conducting body that serves in place of the earth.

Grounded, effectively--(Over 600 volts, nominal.) Permanently connected to earth through a

ground connection of sufficiently low impedance and having sufficient ampacity that ground fault

current which may occur cannot build up to voltages dangerous to personnel.

Grounded conductor--A system or circuit conductor that is intentionally grounded.

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