Pennsylvania Code › Title 34 - LABOR AND INDUSTRY › Part I - Department of Labor and Industry › Chapter 39 - SAFETY STANDARDS-GENERAL › Subchapter B - ELECTRIC SAFETY › GENERAL PROVISIONS › Section 39.51 - Definitions

Current through Register Vol. 54, No. 28, July 13, 2024
The following words and terms, when used in this
						subchapter, have the following meanings, unless the context clearly indicates
						otherwise:
Alive
or
live
-Electrically connected to a source of potential
						differences or electrically charged so as to have a potential different from
						that of the earth. This term may be used in place of the term
						"current-carrying" where the intent is clear, to avoid repetitions of the
						longer term.
Apparent sag (at any point)
-The
						departure of the wire at the particular point in the span from the straight
						line between the two points of support of the span, at 60°F with no wind
						loading.
Apparent sag of a span
-The departure of
						the wire in a given span from the straight line between the two points of
						support of the span, at 60°F with no wind loading. If the two supports are
						at the same level this shall be the normal sag.
Authorized
-Qualified.
Automatic
-Self-acting, operating by its
						own mechanism when actuated by some impersonal influence, as for example, a
						change in current strength, not manual, without personal intervention. Remote
						control which requires personal intervention is not automatic, but
						manual.
Cable vault
-Manhole.
Chief operator
-The official in charge of
						safeguarding operations.
Circuit
-A conductor or system of
						conductors through which an electric current is designed to flow, and connected
						equipment.
Climbing space
-The vertical space
						reserve along the side of a pole structure to permit ready access for linemen
						to equipment and lines located on the pole structure.
Conductor
-A metallic conducting
						material, usually in the form of a wire or cable, suitable for carrying an
						electric current, not including bus bars.
Conflicting
-If applied to a pole line,
						this term shall mean a line so situated with respect to a second line, except
						at crossings, that the overturning of the first line will result in contact
						between its poles or conductors and the conductors of the second line, assuming
						that no conductors are broken in either line. Lines on opposite sides of a
						highway, street or alley are not considered as conflicting if separated by a
						distance not less than 60% of the height of the taller pole line, but in no
						case less than 20 feet.
Conduit
-If used in reference to
						underground work, this term shall mean a group of any number of ducts for
						underground cables.
Current-carrying part
-A part intended to
						be connected in an electric circuit to a source of voltage. Noncurrent-carrying
						parts are those not intended to be so connected.
Cutout
-Any device, such as a fuse or
						circuit breaker, by which the electrical continuity of a conductor may be
						automatically broken by changes in current or voltage.
Dead
-Free from any electrical connection
						to a source of potential difference and from electrical charge; not having a
						potential different from that of the earth. This term is used only with
						reference to current-carrying parts which are sometimes alive.
Disconnector
-A switch intended to open a
						circuit only after the load has been thrown off by some other means. Manual
						switches designed for opening circuits are usually installed in circuit with
						disconnectors to provide a safe means for opening the circuit under
						load.
Duct
-If used in reference to underground
						work, this term shall mean a single tubular runway for underground
						cables.
Electrical supply equipment
-Equipment
						which produces, modifies, regulates, controls, or safeguards a supply of
						electrical energy. Similar equipment is excluded if used in connection with
						signaling systems when the voltage does not exceed 150 or when the voltage is
						between 150 and 400 and the power transmitted does not exceed three
						kilowatts.
Electrical supply lines
-Those conductors
						and their necessary supporting or containing structures which are located
						entirely outside of buildings and are used for transmitting a supply of
						electrical energy. This shall 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 signal lines above 400 volts to ground are always supply
						lines within the meaning of this subchapter and those below 400 volts may be
						considered as supply lines, if so run and operated throughout.
Electrical supply station
-Any building,
						room or separate space within which is located electrical supply equipment and
						which is generally accessible only to properly qualified persons. Included are
						generating stations and substations and generator, storage battery, and
						transformer rooms, but not manholes and isolated transformer vaults on private
						premises.
Enclosed
-In locations where inflammable
						flyings, inflammable dust or explosives are present in dangerous quantities; an
						inclosure which will not admit accumulations of flying or dust, nor transmit
						sparks or flying particles to the accumulation outside.
Explosion-proof
-In locations where the
						presence of inflammable gas makes the atmosphere explosive in character, an
						enclosure which will withstand, without injury and without transmitting flame
						to the outside, any explosion of gas which may occur in the enclosures.
Exposed
-Able to be inadvertently touched
						or approached nearer than a safe distance by any person, as applied to objects
						not suitably guarded or isolated.
Grounded
-Connected to earth or to some
						extended conducting body which serves instead of the earth, whether the
						connection is intentional or accidental.
Grounded system
-A system having a
						permanent and effective electrical connection to earth. Such ground connection
						may be at one or more points. "Effective," as used in this definition, means a
						connection to earth of sufficiently low resistance and high current-carrying
						capacity to prevent any current in the ground wire from causing a harmful
						voltage to exist between the grounded conductors and neighboring exposed
						conducting surfaces which are in good contact with the earth, or with
						neighboring surfaces of the earth itself, under the most severe conditions
						liable to arise in practice.
Guarded
-Covered, shielded, fences,
						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.
Handhole
-An opening in an underground
						system into which workmen reach but do not enter.
Insulated
-Separated from other
						conducting surfaces by a dielectric substance or air space permanently offering
						a high resistance to the passage of current, and to disruptive discharge
						through the substance or space, in suitable manner for the conditions to which
						it is subjected; otherwise within the purpose of these rules, it is
						uninsulated. Insulating covering of conductors is one means of making
						conductors insulated.
Insulating
-If applied to the covering of
						a conductor or to clothing, guards, rods, and other safety devices, this term
						shall mean that a device, when interposed between a person and current-carrying
						parts, protects the person making use of it against electric shock from the
						current-carrying parts with which the device is intended to be used.
Isolated
-Not readily accessible to
						persons unless special means for access are implemented.
Isolated by elevation
-Elevated
						sufficiently so that persons may safely walk underneath.
Lateral conductor
-A wire of cable
						extending in a general horizontal direction approximately at right angles to
						the general direction of the line conductors (in pole wiring work).
Lateral working space
-The space reserved
						for working between conductor levels outside the climbing space, and to its
						right and left.
Line conductor
-A wire or cable carrying
						electric current supported by poles, towers, or other structures, but not
						including vertical or lateral connecting wire.
Manhole
or
cable vault
or
splicing chamber
-An opening in an underground system which
						workmen or others may enter for the purpose of installing cables, transformers,
						junction boxes, and other devices, and for making connections and tests.
Manual
-Operated by personal
						intervention.
Normal sag
-The difference in elevation
						between the highest point of support of a span and the lowest point of the
						conductor in such span, or in the curve of the conductor in the span produced,
						at 60°F with no wind loading.
Open lines
-Overhead lines not in
						conduits, and consisting of single conductors or of individual twisted pairs,
						as opposed to multiple conductor cables.
Panelboard
-A single panel containing
						busses, fuses and switches to control lights, fan motors and similar devices of
						small individual as well as aggregate capacity, placed in or against a wall or
						partition and accessible only from the front.
Permanently grounded
-An effectively
						grounded connection to the earth, by use of an underground system of metallic
						pipe mains or other suitable means.
Pole face
-That side of a pole on which
						crossarms are attached, or which is so designated by the utilities owning or
						operating the pole.
Qualified
or
authorized
-Properly qualified or authorized to perform
						specified duties under the conditions existing. Responsibility for the
						authorization and decision as to the qualifications of employes rests with the
						employer or his agent.
Reconstruction
-Replacement of any
						portion of an existing installation by new equipment or construction, not
						including ordinary maintenance replacements.
Rural districts
-All places not urban,
						usually in the country, but in some cases within city limits.
Service
-The connecting conductors by
						which a supply of electrical energy is carried from a supply line to the
						building or premises served.
Signal lines
-Lines for public or private
						signal or communication service and devoted exclusively to the transmission of
						signals or intelligence, which operate at less than 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. Below 150 volts no limit is placed on the capacity
						of the system. Included are telephone, telegraph, messenger-call, clock, fire,
						or police alarm, and other systems conforming with these requirements. Lines
						used for signaling purposes, but not included under this definition, are
						considered as supply lines of the same voltage and shall so conform. Signal
						lines not for public use coming under this definition may be run and operated
						as supply lines if desired, and if constantly so run.
Splicing chamber
-anhole.
Substantial
-Constructed and arranged to
						be of adequate strength and durability for the service to be performed under
						the prevailing conditions.
Switch
-A device for opening, closing or
						changing the connection of a circuit manually. In this subchapter, a switch
						shall be always considered manually operated, unless otherwise stated.
Switchboard
-A large single panel or
						assembly of panels on which are mounted, partly on the face and partly on the
						back, switches, fuses, busses and usually instruments, and accessible both in
						front and in rear. Circuits and machinery of relatively large capacity are
						controlled from these boards.
Tags
-Tags of distinctive appearance,
						indicating that the equipment or lines marked are being worked on.
Transformer vault
-An isolated, fireproof
						enclosure, either above or below ground, in which transformers and the devices
						necessary for their operation are installed, and which is not continuously
						under attendance during operation.
Urban districts
-Thickly settled
						communities, whether in cities or suburbs, where congested traffic often
						occurs. A highway, though in the country, on which the traffic is often very
						heavy, is considered urban.
Utilization equipment
-Equipment,
						devices, and connected wiring, which utilize electrical energy for mechanical,
						chemical, heating, lighting, testing or similar purposes and are not a part of
						supply equipment, supply lines or signal lines.
Vertical conductor
-A wire or cable
						extending in approximately vertical direction, in pole wiring work.
Voltage
or
volts
-The
						highest effective voltage between the conductors of the circuit concerned,
						except that in grounded multiwire circuits not exceeding 750 volts between
						outer conductors it means the highest effective voltage between any wire of the
						circuit and the ground. In ungrounded low-voltage circuits "voltage to ground"
						means the voltage of the circuit. If one circuit is directly connected to
						another circuit of higher voltage as in the case of an autotransformer, both
						are considered to be of the higher voltage, unless the circuit of lower voltage
						is permanently grounded. Direct connection implies electrical connection as
						distinguished from connection merely through electromagnetic or electrostatic
						induction.
Wire gauges
-The American Wire Gauge
						(A.W.G.), otherwise known as Brown & Sharpe (B. & S.) is the standard
						gauge for copper, aluminum, and other conductors, excepting steel, for which
						the Steel Wire Gauge (Stl. W. G.) is used throughout this
						Subchapter.
This section cited in 34 Pa. Code §
													39.472 (relating to live
						  electrical parts).