Alive or live (energized). The term means electrically connected to a source of potential difference,
or electrically charged so as to have a potential significantly different from that of the earth in the vicinity. The term "live" is sometimes used in
place of the term "current-carrying," where the intent is clear, to avoid repetition of the longer term.
Automatic circuit recloser. The term means a self-controlled device for automatically interrupting and
reclosing an alternating current circuit with a predetermined sequence of opening and reclosing followed by resetting, hold closed, or lockout
Barrier. The term means a physical obstruction which is intended to prevent contact with energized
lines or equipment.
Barricade. The term means a physical obstruction such as tapes, screens, or cones intended to warn and
limit access to a hazardous area.
Bond. The term means an electrical connection from one conductive element to another for the purpose of
minimizing potential differences or providing suitable conductivity for fault current or for mitigation of leak- age current and electrolytic
Bushing. The term means an insulating structure including a through conductor, or providing a
passageway for such a conductor, with provision for mounting on a barrier, conducting or otherwise, for the purpose of insulating the conductor from
the barrier and conducting current from one side of the barrier to the other.
Cable. The term means a conductor with insulation, or a stranded conductor with or without insulation
and other coverings (single-conductor cable) or a combination of conductors insulated from one another (multiple-conductor cable).
Cable sheath. The term means a protective covering applied to cables.
NOTE: A cable sheath may consist of multiple layers of which one or more is conductive.
Circuit. The term means a conductor or system of conductors through which an electric current is
intended to flow.
Communication lines. The term means the conductors and their supporting or containing structures which
are used for public or private signal or communication service, and which operate at potentials not exceeding 400 volts to ground or 750 volts between
any two points of the circuit, and the transmitted power of which does not exceed 150 watts. When operating at less than 150 volts no limit is placed
on the capacity of the system.
NOTE: Telephone, telegraph, railroad signal, data, clock, fire, police-alarm, community television antenna, and other systems conforming
with the above are included. Lines used for signaling purposes, but not included under the above definition, are considered as supply lines of the
same voltage and are to be so run.
Conductor. The term means a material, usually in the form of a wire, cable, or bus bar suitable for
carrying an electric current.
Conductor shielding. The term means an envelope which encloses the conductor of a cable and provides an
equipotential surface in contact with the cable insulation.
Current-carrying part. The term means a conducting part intended to be connected in an electric circuit
to a source of voltage. Non-current-carrying parts are those not intended to be so connected.
Dead (deenergized). The term means free from any electrical connection to a source of potential
difference and from electrical charges: Not having a potential difference from that of earth.
NOTE: The term is used only with reference to current-carrying parts which are sometimes alive (energized).
Designated employee. The term means a qualified person delegated to perform specific duties under the
Effectively grounded. The term means intentionally connected to earth through a ground connection or
connections of sufficiently low impedance and having sufficient current-carrying capacity to prevent the buildup of voltages which may result in undue
hazard to connected equipment or to persons.
Electric line trucks. The term means a truck used to transport men, tools, and material, and to serve
as a traveling workshop for electric power line construction and maintenance work. It is sometimes equipped with a boom and auxiliary equipment for
setting poles, digging holes, and elevating material or men.
Enclosed. The term means surrounded by a case, cage, or fence, which will protect the contained
equipment and prevent accidental contact of a person with live parts.
Equipment. This is a general term which includes fittings, devices, appliances, fixtures, apparatus,
and the like, used as part of, or in connection with, an electrical power transmission and distribution system, or communication systems.
Exposed. The term means not isolated or guarded.
Electric supply lines. The term means those conductors used to transmit electric energy and their
necessary supporting or containing structures. Signal lines of more than 400 volts to ground are always supply lines within the meaning of the rules,
and those of less than 400 volts to ground may be considered as supply lines, if so run and operated throughout.
Guarded. The term means protected by personnel, covered, fenced, or enclosed by means of suitable
casings, barrier rails, screens, mats, platforms, or other suitable devices in accordance with standard barricading techniques designed to prevent
dangerous approach or contact by persons or objects.
NOTE: Wires, which are insulated but not otherwise protected, are not considered as guarded.
Ground. (Reference). The term means that conductive body, usually earth, to which an electric potential
Ground (as a noun). The term means a conductive connection whether intentional or accidental, by which
an electric circuit or equipment is connected to reference ground.
Ground (as a verb). The term means the connecting or establishment of a connection, whether by
intention or accident of an electric circuit or equipment to reference ground.
Grounding electrode (ground electrode). The term grounding electrode means a conductor embedded in the
earth, used for maintaining ground potential on conductors connected to it, and for dissipating into the earth current conducted to it.
Grounding electrode resistance. The term means the resistance of the grounding electrode to
Grounding electrode conductor (grounding conductor). The term means a conductor used to connect
equipment or the grounded circuit of a wiring system to a grounding electrode.
Grounded conductor. The term means a system or circuit conductor which is intentionally
Grounded system. The term means a system of conductors in which at least one conductor or point
(usually the middle wire, or neutral point of transformer or generator windings) is intentionally grounded, either solidly or through a
current-limiting device (not a current-interrupting device).
Hotline tools and ropes. The term means those tools and ropes which are especially designed for work
on energized high voltage lines and equipment. Insulated aerial equipment especially designed for work on energized high voltage lines and equipment
shall be considered hot line.
Insulated. The term means separated from other conducting surfaces by a dielectric substance
(including air space) offering a high resistance to the passage of current.
NOTE: When any object is said to be insulated, it is understood to be insulated in suitable manner for the conditions to which it is
subjected. Otherwise, it is within the purpose of this subpart, uninsulated. Insulating covering of conductors is one means of making the conductor
Insulation (as applied to cable). The term means that which is relied upon to insulate the conductor
from other conductors or conducting parts or from ground.
Insulation shielding. The term means an envelope which encloses the insulation of a cable and provides
an equipotential surface in contact with cable insulation.
Isolated. The term means an object that is not readily accessible to persons unless special means of
access are used.
Manhole. The term means a subsurface enclosure which personnel may enter and which is used for the
purpose of installing, operating, and maintaining equipment and/or cable.
Pulling tension. The term means the longitudinal force exerted on a cable during
Qualified person. The term means a person who by reason of experience or training is familiar with the
operation to be performed and the hazards involved.
Switch. The term means a device for opening and closing or changing the connection of a circuit. In
these rules, a switch is understood to be manually operable, unless otherwise stated.
Tag. The term means a system or method of identifying circuits, systems or equipment for the purpose
of alerting persons that the circuit, system or equipment is being worked on.
Unstable material. The term means earth material, other than running, that because of its nature or
the influence of related conditions, cannot be depended upon to remain in place without extra support, such as would be furnished by a system of
Vault. The term means an enclosure above or below ground which personnel may enter and is used for the
purpose of installing, operating, and/or maintaining equipment and/or cable.
Voltage. The term means the effective (rms) potential difference between any two conductors or between
a conductor and ground. Voltages are expressed in nominal values. The nominal voltage of a system or circuit is the value assigned to a system or
circuit of a given voltage class for the purpose of convenient designation. The operating voltage of the system may vary above or below this
Voltage of an effectively grounded circuit. The term means the voltage between any conductor and
ground unless otherwise indicated.
Voltage of a circuit not effectively grounded. The term means the voltage between any two conductors.
If one circuit is directly connected to and supplied from another circuit of higher voltage (as in the case of an autotransformer), both are
considered as of the higher voltage, unless the circuit of lower voltage is effectively grounded, in which case its voltage is not determined by the
circuit of higher voltage. Direct connection implies electric connection as distinguished from connection merely through electromagnetic or