Code of Massachusetts Regulations › 220 CMR - DEPARTMENT OF PUBLIC UTILITIES › Title 220 CMR 125.00 - Installation And Maintenance Of Electric Transmission Lines › Section 125.40 - Definitions

Current through Register 1525, July 5, 2024
The following definitions are for use with the Massachusetts
		  Code for the Installation and Maintenance of Electric Transmission Lines. For
		  other use and for definitions not contained herein, see Definitions of
		  Electrical Terms, ANSI C42.35.
Circuit
. A conducting part or a system
		  of conducting parts through which an electric current is intended to
		  flow.
Conductor
. A wire or combination of
		  wires not insulated from one another, suitable for carrying electric
		  current.
Grounding Conductor
. A conductor which
		  is used to connect the equipment or structure with a grounding system.
Department
. The Massachusetts
		  Department of Public Utilities.
Ground
. A conducting connection,
		  whether intentional or accidental, by which an electric circuit is connected to
		  the earth, or to some conducting body, of relatively large extent, which serves
		  in place of earth. It is used for establishing and maintaining the potential of
		  the earth (or of the conducting body) or approximately that potential, on
		  conductors connected to it, and for conducting ground current to and from the
		  earth (or the conducting body).
(a)
Grounded
. Grounded means that the
		  system, circuit, or apparatus referred to is provided with a ground.
(b)
Effectively Grounded
. Grounded
		  through a grounding connection of sufficiently low impedance (inherent or
		  intentionally added or both) that fault grounds which may occur cannot build up
		  voltages in excess of limits established for apparatus, circuits, or systems so
		  grounded.
(c)
Effectively Grounded System
. A
		  system in which, for all points on the system or specified portion thereof in
		  the ratio of zero-sequence reactance to positive-sequence reactance is positive
		  and not greater than three and the ratio of zero-sequence resistance to
		  positive-sequence reactance is positive and not greater than one for any
		  condition of operation and for any amount of connected generator capacity.
Guarded
. Covered, shielded, fenced,
		  enclosed or otherwise protected, by means of suitable covers or casings,
		  barrier rails or screens, mats or platforms, to remove the liability of
		  dangerous contact or approach by persons or objects to a point of danger. Wires
		  which are insulated but not otherwise protected are not considered as
		  guarded.
Guy. A tension member having one end secured to a fixed object
		  and the other end attached to a pole, crossarm or other structural part which
		  it supports.
Anchor Guy
. A tension member having
		  one end secured in the ground and the other end attached to a pole, crossarm or
		  other structural part which it supports.
Insulated
. Separated from other
		  conducting surfaces by a dielectric permanently offering a high resistance to
		  the passage of current and to disruptive discharge. 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
		  220 CMR 125.00,
		  uninsulated.
Isolated
. Means that an object is not
		  readily accessible to persons unless special means for access are used.
Lines.
(a)
Communication Lines
. The
		  conductors and their supporting or containing structures which are located
		  outside of buildings and are used for public or private signal or communication
		  service, and which operate at not exceeding 400 V to ground or 750 V between
		  any two points of the circuit, and the transmitted power of which does not
		  exceed 150 W. When operating at less than 150 V no limit is placed on the
		  capacity of the system. Telephone, telegraph, railroad-signal, messenger-call,
		  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.
(b)
Electric-Supply Lines
. Those
		  conductors and their necessary supporting or containing structures which are
		  located entirely outside of buildings and are used for transmitting electric
		  energy at a phase to phase voltage less than 50,000 V. Does not include open
		  wiring on buildings, in yards or similar locations where spans are less than 20
		  feet, and all the precautions required for stations or utilization equipment,
		  as the case may be, are observed.
Railway sign allines of more than 400 V to ground are always
		  supply lines within the meaning of
		  220 CMR 125.00, and those of
		  less than 400 V may be considered as supply lines, if so run and operated
		  throughout.
(c)
Transmission Lines
. Those
		  conductors and their necessary supporting or containing structures which are
		  located entirely outside of buildings and are used for transmitting electric
		  energy at a phase to phase voltage exceeding 50,000 V.
(10)
Reconstruction
. Replacement of
		  any portion of an existing installation by new equipment or construction.
		  Reconstruction does not include ordinary maintenance replacements.
(11)
Sag
.
(a)
Final Unloaded Sag
. The sag of a
		  conductor after it has been installed for a long period of time or after it has
		  been subjected to external load for an appreciable period of time and the
		  loading removed.
(b)
Initial Unloaded Sag
. The sag of a
		  conductor immediately after installation.
(c)
Unloaded Sag of a Conductor at Any Point in a
		  Span
. The distance measured vertically from the particular point
		  in the conductor to a straight line between its two points of support, without
		  any external load.
(12)
Span Wire
. A wire or cable used
		  as an auxiliary support for wires, cables or equipment. While not normally used
		  to carry current, it may do so under certain abnormal conditions.
(13)
Tension
.
(a)
Final Unloaded Conductor Tension
.
		  The longitudinal tension in a conductor after it has been installed for a long
		  period of time after it has been subjected to external load for an appreciable
		  period of time and the loading removed.
(b)
Initial Conductor Tension
. The
		  longitudinal tension in a conductor immediately after installation.
(14)
Voltage
.
(a)
Voltage of an Effectively Grounded
		  Circuit
. The highest effective voltage between any conductor and
		  ground unless otherwise indicated.
(b)
Voltage of a Circuit Not Effectively
		  Grounded
. The highest effective voltage between any two conductors
		  unless otherwise indicated.
If one circuit is directly connected to another circuit of
		  higher voltage (as in the case of an auto-transformer), 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 electrostatic induction.
(c)
Voltage to Ground of an Effectively Grounded
		  Circuit
. The highest effective voltage between any conductor of
		  the circuit and that point of the circuit which is grounded.
(d)
Voltage to Ground of a Conductor of an
		  Effectively Grounded Circuit
. The highest effective voltage
		  between such conductor and that point or conductor of the circuit which is
		  grounded.