Glossary of Terms Flashcards
(142 cards)
1
Q
What Is American Wire Gauge (AWG).
A
A standard wire gauge system for round, solid, electrically
conducting wire.
2
Q
What Is The smallest AWG wire size
A
The smallest AWG wire size is #41 which is a 0.0028 inches
3
Q
what is the largest wire size in AWG system?
A
pronounced “4 aught” which is 0.4600 inches in diameter.
4
Q
What Is asperity.
A
As used in cable splicing, the unevenness or roughness of a surface. The many sharp,
rough projections from a surface are called asperities.
5
Q
What Is backfeed
A
Occurs then power flows in the opposite direction from its usual flow. For example,
backfeed occurs when customer-generated power (PV panels, portable generators) are present.
Backfeed can occur in a de-energized phase of a three-phase transformer when one or more of
the other phases of that transformer are energized.
6
Q
What Is BIL.
A
Basic insulation level. A measure of the ability of an insulation to withstand a specified
voltage. The point at which tracking will occur, leading to an arcing flashover. Also called basic
impulse insulation level.
7
Q
What Is boiling out.
A
The process of pouring hot insulating oil over the insulation of a cable to rid the
area of contaminants and moisture.
8
Q
What Is branch splice.
A
A type splice used to connect three connectors together. Also called a T splice.
9
Q
What Is bunch stranding.
A
A collection of strands of conductors twisted together in the same direction
without regard to the geometrical arrangement.
10
Q
What Is butyl rubber.
A
A synthetic rubber produced with the use of butylene, a gas. Butyl rubber offers a
large resistance to penetration by gases such as ozone.
11
Q
who is cable splicer.
A
The person in whom confidence is placed to make a electrically reliable and
mechanically strong splice or termination, usually of a medium-voltage sable.
12
Q
What Is capacitor.
A
Two conductors separated by an insulating dielectric. A conductor, its insulation, and
a shield form a capacitor.
13
Q
What Is chamfering.
A
A technique used to remove sharp corners from an insulation layer, usually done
with a knife or special tool.
14
Q
What Is CIC.
A
CIC. Cable in conduit.
15
Q
What Is circular mil.
A
A measurement equal to the area of a circle with a diameter of one-thousandth of
an inch. Commonly used for the cross-sectional area of a conductor.
16
Q
What Is Class termination.
A
**A Class 1 termination provides (1) electrical stress control at the end of the cable insulation shield, (2) external leakage insulation (tracking protection) between the cable conductor(s) and ground, and (3) a seal at the end of the cable to protect from entrance by the external environment. A Class 2 termination provides (1) and (2). A Class 3 termination provides only (3).**
17
Q
What Is clearance (for working).
A
Specific permission to work on lines or equipment, including identification for specific persons(s) receiving permission and granting permission from the proper authority.
18
Q
What Is CN.
A
Bare concentric neutral.
19
Q
What Is cold shrink splice.
A
A type of splice in which a rubber tube is shrunk over a cable splice by pulling
a tab extending from the tube.
20
Q
What Is compression connector.
A
- *A metal connector that can be secured to a cable by compressing or
crimping. **
21
Q
What Is concentric wires.
A
A layer of spiral-wrapped wires used as a system neutral (on primary or
secondary cable) or to bleed off excessive static charges (on primary cable only).
22
Q
What Is conductive breakout tube.
A
A heat-shrink tube used to electrically connect the conductive shields
of individual cables to the lead cover of PILC cable. Used when making a trifurcating transitional
splice.
23
Q
What Is conductor.
A
A material which offers little opposition to current flow. Copper and aluminum are
commonly used conductors for medium voltage cable. Ozone is a gas conductor that can result
from air pockets in medium- and high-voltage cables.
24
Q
What Is conductor shield.
A
shield. A layer of semi-conductive material directly around a conductor that gives a
stranded conductor a more uniformly round shape to reduce the concentration of voltage stress
at the high points of the round conductor strands.
25
**What Is conductor strand sealant.**
**A material applied to a stranded conductor to impede longitudinal
water flow down the conductor.**
26
**What Is copper shielding tape**
**Tape applied to some primary tape splices over the insulation shield layer,
to provide added stress relief.**
27
**What Is corona.**
**The partial breakdown of the air around higher voltage conductors.**
28
**What Is corona cutting.**
**The damage resulting from corona discharge. Corona cutting appears as burnt
spots and pitting on the conductor jacket or in the conductor insulation. Corona cutting will
cut away sufficient cable jacket to cause failure of the insulation and eventual breakdown of the
cable.**
29
**What Is corona level.**
**The corona level is the AC voltage level that will sustain corona discharge.**
30
**What Is corona discharge.**
**A continuous electrical discharge that produces ozone which can lead to the
deterioration of insulation.**
31
**What Is creepage distance.**
**The distance between the end of a conductor and the insulation shield. Also
called leakage distance.**
32
**cross-linked polyethylene (XLP or XLPE).**
**A thermoset material used for cable insulation.
It can operate at high temperature, is light in weight, abrasion resistant, and not affected by
most chemicals. During the manufacturing process individual molecules in XLPE material
are joined together (cross-linked) to form an interconnected network that can operate at high
temperatures.**
33
**What Is dead.**
**Disconnected from any electrical source or supply, properly tagged, shorted, and
grounded. Normally used in reference to certain parts of the electrical system such as lines,
cables, or equipment.**
34
**What Is dead front.**
**Equipment or devices that have no exposed energized parts greater than 600 volts,
and cables and terminations have an effectively grounded metallic shield.**
35
**What Is deadbreak.**
**A termination or switching point that can be safely separated only when no current
is flowing through it. Also called non-loadbreak.**
36
**What Is dielectric.**
**An insulator which, when placed between two conductors, can be polarized. Electrons
in the material are attracted to one conductor and repelled from the other conductor, forming an
electric field. The term "dielectric" is from "dia-electric."**
37
**What Is dielectric constant.**
**A measure of the ability of a material to store a charge. The dielectric
constant of air is 1, of polyethylene is 2.3, of butyl rubber is 3.7. See also K factor.**
38
**What Is disconnected**
**An electrical attachment removed from any electrical source.**
39
**double branch splice.**
* *A variation of the branch splice used for multiple branching from a splice
point. **
40
**What Is drain wire.**
**A small wire, usually #14 copper, that connects a cable accessory to ground to
prevent the buildup of static charge due to capacitive coupling. Note: This wire is not intended to
carry fault current.**
41
**drain wire tab.**
**A tab on a cable accessory which accepts a small wire, usually #14 AWG copper,
to prevent the buildup of static charge due to capacitive coupling.**
42
**effectively grounded.**
**Intentionally attached to earth through a ground connection or connec-tions of sufficiently low impedance. This connection has sufficient current-carrying capacity to prevent a buildup of voltage or fault current that could be hazardous to connected equipment or personnel.**
43
**What Is elastomer.**
**A rubber-based insulating material used with synthetic rubbers. Elastic or stretchy
dielectric with considerable bounce-back.**
44
**What Is electrostatic.**
**electrostatic. Electrical particles that are stationery or at rest.**
45
**What Is electrostatic field.**
**The region near or around an electrically charged object such as a conductor
charged with a voltage. The region around an electric charge is under strain in a manner similar
to that of the region around a magnetic pole. The field consists of electrostatic lines or paths,
that positive charges would take when moving toward a negatively charged object. As the voltage
increases, the strength of the electrostatic field increases.**
46
**What Is equipotential lines.**
**lines. Lines of equal voltage in the space between two conductors with different
voltages. In a shielded cable, the lines of equal voltage in the insulation between the center
conductor and the cable shield.**
47
**What Is erosion distance.**
**The ability of electrical insulation to resist erosion. Failure occurs by dielectric breakdown after the insulation is eroded
to a much reduced thickness. Erosion resistance is measured by its time-to-failure.**
48
**What Is ethylene propylene (EP) (EPR).**
**A rubber-based, thermoset material used for cable insulation. It
is able to withstand high temperatures. Used mostly within industrial sites.**
49
**What Is exposed.**
**Equipment, objects or devices not guarded, insulated or shielded to earth.**
50
**What Is fault.**
**In an electric power system, a fault is an unwanted flow of current. A short-circuit fault occurs when the current bypasses the load. A ground fault is a type of short-circuit fault where current flows directly into the neutral or earth. An open-circuit fault occurs when the normal flow of current is stopped by some failure. In a power system, protective devices detect faults and operate circuit breakers, fuses, and other devices to provide worker safety, and to limit the loss of
service to customers.**
51
**What Is floating shield**
**A cable shield which is not grounded. When there is no ground on the shield, the entire shield is floating and can be dangerous because the shield is not at ground potential. For
most installations, the shield is grounded at least at one end. The end that is not grounded is said
to be floating but the shield is at ground potential.**
52
**What Is flux lines.**
**lines. Lines that show the alignment of magnetic particles in the space between a positively charged material and a negatively charged material. Flux lines are formed whenever a conductor is energized. The strength of flux lines is proportional to the voltage between the materials.**
53
**What Is gradient, potential gradient.**
**Volts-per-unit-of-thickness across a dielectric. Example: 4,160 volts
across 10 mils of insulation is a potential gradient of 416 volts per mil.**
54
**What Is grounded.**
**A connection to earth, or other conductor taking the place of earth. The shield of medium voltage cable is grounded so the shield is at the same potential as the cable surface and its surrounding medium. The shield can be grounded at one end or both ends, as determined by specifications of the system being installed.**
55
**What Is grounding eye.**
**A connection point for a single concentric wire on a pre-molded slip-on primary
splice, to ensure contact between the concentric wire layer and the insulation shield layer of the
splice.**
56
**What Is heat shrink splice.**
**A type of splice in which a plastic tube is heated to shrink and adhere tightly
to the cable.**
57
**What Is induced voltage.**
**A electric potential created in one conductor because it is in the electricmagnetic field of a nearby conductor.**
## Footnote
**Induced voltage can be intentional; for example, the
voltage across the secondary winding of a transformer is intentionally induced by being close to the primary winding. Induced voltage can be unintentional; for example, a de-energized conductor can have an unintentional voltage induced on it by a nearby energized conductor. Unintentional induced voltages are sometimes called ghost voltages. Induced voltages are caused
by magnetic coupling (example: between transformer coils) and by electric coupling (example: between two conductors acting like the two plates of a capacitor).**
58
**What Is insulated.**
**Separated from other conducting surfaces by a dielectric material and/or air-space.**
59
**What Is insulation.**
**A material which offers a great opposition to the flow of current, used to prevent the leakage of electricity from a conductor. The ability of the insulation to contain electricity within the conductor is known as its dielectric strength. Butyl rubber, insulating oil, paper, varnished cambric, are examples of insulation with high dielectric strength used as insulation in medium voltage power cables.**
60
**What Is insulation and shielding tube.**
**A heat-shrink splice tube designed to provide both insulation and shielding for a trifurcating transitional splice.**
61
**What Is insulation layer**
**The layer of insulating material directly over the cable's conductor shield layer.**
62
**What Is insulation shield.**
**A layer of semi-conductive shielding placed over cable insulation to provide a
uniform ground potential and evenly distribute voltage stress through the cable's insulation.**
63
**What Is ionic emission.**
**emission. The process of ejecting electrons from the surface of a material by the use of a high voltage or other means. In the case of medium voltage power cable, the voltage of the circuit which is impressed on the conductor which can cause electrons to be ejected out of the
conductor and fired at the insulation surrounding the conductor subjecting the insulation to a beating, such as the beating of a piece of meat to tenderize it. Ionic emission is also called bombardment.**
64
**What Is ionization.**
**The breaking up of the gas molecules into positively and negatively charged ions. Ionization takes place in air pockets (voids) within a medium voltage power cable, or between the cable and its surrounding insulation. To start the action a corona discharge takes place in the air pocket causing ionization of the air, resulting in an ozone gas. The ozone serves as a gas conductor which allows the corona discharge to continue to break down the insulation, while at the same time the ozone will have a harmful chemical effect on the insulation.**
65
**What Is jacket.**
**The outermost layer of a cable to protect it from physical and environmental abuse. The type of jacket depends on the requirements of the installation. Example: neoprene jacketed cable is used where its characteristics can be used to an advantage, such as its ability to resist abrasion,
cutting, flame, oil, ozone, sunlight, tearing, and weathering.**
66
**What Is kcmil.**
**A unit of conductor area for wires larger than 0000 AWG. One circular mil (cmil) is equal to the area of a circle with a diameter of one mil (0.001 inch). In practice, this size is too small to be usable for wire sizes. Therefore, sizes are usually given in thousands of circular mils, or kcmil. One kcmil is a circle containing the area of 1,000 circular mils. For example, a wire with a cross- sectional area of 250,000 circular mils is written as 250 kcmil. This is the first wire size larger
than 0000 AWG. See Appendix C. See also MCM.**
67
**What Is K factor**
**A dimensionless parameter that measures the electrostatic energy per unit volume, that a material can store. The higher the K factor, the better the ability of the material to manage
voltage stress. Materials with high K factors allow the use of thinner insulation.**
68
**What Is lead sheath.**
**sheath. On single-phase PLIC cables, a protective layer that functions as a metallic conductive
insulation
shield.**
69
**What Is lead wiping.**
**The process of pouring melted solder and then wiping it with a fi re-retardant cloth to seal the splice area.**
70
**What Is live front.**
**Equipment or devices having exposed energized components over 600 volts.**
71
**What Is live front.**
**Equipment or devices having exposed energized components over 600 volts.**
72
**What Is loadbreak.**
**A termination or switching point that can be safely separated while carrying full load current.**
73
**What Is longitudinal cut.**
**A cut made parallel to the conductor.**
74
**What Is longitudinal stress.**
**Longitudinal means: running the length of the cable.**
## Footnote
**The collection of static charges on the braid or outer covering of the cable which causes a capacitor effect between the conductor in the cable, the insulation on the cable, and the conduit it is enclosed in, or the
ground it is near, risking an arc discharge between the conductor and the conduit or surrounding ground which damages the cable insulation or jacket. Longitudinal stress is compensated for by using a metallic shielding system and the shield grounded**
75
**What Is mastic tape**
**A highly conformable insulation tape used on splices and terminations as
insulation and to seal out moisture.**
76
**What Is MCM.**
**Thousand circular mils. An area commonly used to measure the total cross-sectional area of a stranded or solid wire or conductor. Same as kcmil.**
77
**What Is medium voltage**
**Voltages from 2001 to 35,000 volts is the official definition (NEC Section 328).
Other sources consider 46 kV as the high end.**
78
**What Is metallic shield.**
**A cable layer that surrounds the insulation shield and minimizes corona (static)
discharge on the outer surface of the cable. Also, can act as the system neutral.**
79
**What Is metallic shield water block**
**A material (tape, powder, or other material) applied between the
cable metallic shield and cable jacket to impede water migration longitudinally along the cable.**
80
**What Is mil.**
**One one-thousandth of an inch. 0.001 inch.**
81
**non-load break.**
**break. A termination or switching point that can be safely separated only when there is no current flowing through it. Also called deadbreak.**
82
**What Is oil barrier tubing**
**A semi-transparent heat shrink tube that works together with stress relieving
material to keep the oil on a PILC cable's paper insulation. Used when making a trifurcating
transitional splice.**
83
**What Is oil stop connector.**
**A type of compression connector that has a stop or dam, in the center of its
barrel to keep oil away from the solid dielectric cable in a transitional splice.**
84
**What Is oxide inhibitor**
* *inhibitor. A material used to coat a metallic conductor (usually aluminum) to prevent the buildup of oxides on the surface of the conductor. Some oxide inhibitors include abrasive particles that help break up oxides on oxidized conductors. Oxide inhibitors are used to promote rlong-term low-resistance connections between aluminum conductors and other conductors or
connectors. **
85
**What Is ozone.**
**A light-blue conductive gas that smells somewhat like chlorine bleach. It is an active chemical which can cause harmful chemical effects on dirt and insulation. Ozone is formed in the air by lightning, when electric sparks at the brushes of a motor or generator, at the contacts of a starter, and when there is an arc discharge within or on the surface of a conductor or cable.**
86
**What Is rpaper pasters**
**Material used to limit the flow of solder when a component is being tinned.**
87
**What Is partial discharge.**
**Localized electrical discharge that only partially bridges the insulation between conductors.**
88
**What Is penciling.**
**A technique that tapers the insulation on a cable to increase the creep age distance
and provide a smooth transitional surface.**
89
**What Is permittivity.**
**The ability of a material to store electrical potential under the influence of an
electric field. A measure of how easily it polarizes. Also called dielectric constant.**
90
**What Is personal protective equipment.**
**Items donned by personnel to protect them from unnecessary
exposure to hazards of their job. PPE may be applied to protect the head, face, ears, respiratory
system, hands, arms, feet, legs, and their trunk.**
91
**What Is PILC. paper-insulated lead-covered.**
**A type of primary cable with impregnated paper insulation
wrapped round a shielded conductor, and covered with a
flexible lead covering. Also called****paper-in-lead cable.**
92
**What are polymers.**
**Any of two or more polymeric compounds.**
93
**What Is polyvinyl chloride**
* *(PVC). A plastic insulation commonly used for low voltage cables up to 5,000
volts. **
94
**pothead**
* *A termination assembly that seals the ends of cables against moisture and contamina-
tion. "Pot" is believed to be derived from "porcelain outdoor terminal."**
95
**What Is radial stress**
**Radial stress is associated with the radial flux lines of the conductor's voltage and are present in the dielectric or insulation whenever the conductor is energized.**
96
**What Is reinforcing tube.**
**A splice tube with heat-shrink adhesive that seals and protects a trifurcating
transitional splice from the outside environment.**
97
**What Is ring cut.**
**A cut made around the circumference of a cable. Also called a radial cut.**
98
**rolling ring seal splice**
**A secondary splice that uses rubber 0-rings and an insulating tube to
form a water-tight seal.**
99
**What Is sector conductor.**
**conductor. A stranded conductor whose cross-section is approximately the shape of a sector of a circle. A multi-conductor insulated cable with sector conductors has a smaller
diameter than the corresponding cable with round conductors.**
100
**What Is segmental conductor.**
**conductor. A round, stranded conductor composed of three or four sectors slightly
insulated from one another. This construction has less skin effect.**
101
**What Is semi-conducting tape.**
**A tape applied between insulation and a conductor to provide an
intimate contact between the them. Because the contact is gap-free, the voltage is the same on both surfaces, so the electric field is contained in the insulation. Semi-con is not a good conductor so line current is carried by the conductor, not the semi-con. Semi-con tape is applied between the conductor and the insulation, and between the insulation and the shield. It is also used to build stress cones.**
102
**What Is shield.**
**A metallic cover which surrounds the insulator around a conductor, to confine the
electric field to the insulation. The shield of power cables is usually grounded.**
103
**What Is shield adapter.**
**A product used to adapt a metallic shield to connect to the system ground.**
104
**What Is skin effect.**
**Concentration of the current density near the surface of a conductor. Skin effect increases with frequency. It causes an effective increase in the impedance resulting in losses and
reduced ampacity. It also adds to the stress on the insulation.**
105
**What Is slip bolt**
**A mechanical connector consisting of a slotted, threaded nut and bolt into which two conductor ends are inserted. Used on lower voltage cables, and occasionally for temporary
emergency splices of medium voltage cables.**
106
**What Is slip-on splice.**
* *A cable splice that uses a remolded insulating tube that slips over a compression
connector. **
107
**What Is splice.**
**The joining of cable ends together while maintaining the original electrical and mechanical characteristics of the cables.**
108
**What Is splice kit.**
**A pre-assembled kit containing all or most of the parts necessary to make a cable spice.**
109
**What Is SRM**
**stress relief mastic.**
110
**What Is static voltage.**
**A build-up of an electrical charge on the surface of a material due to friction or
other conditions. The charge remains on the surface until it is able to discharge.**
111
**What Is strand shielding.**
**The process whereby semi-conducting tape is applied over the surface of a stranded conductor, making an intimate contact between the conductor and insulation. It gives the stranded conductor the characteristics of a round conductor, thus reducing radial and tangential voltage stress.**
112
**What Is straight splice.**
**splice. A cable splice that joins two cables of the same design.**
113
**What Is stress cone.**
**A buildup of insulating tape on a cable termination to issipate the concentration of flux lines, equipotential lines, and ongitudinal stresses caused by the abrupt ending of the shield.**
114
**What Is stress control putty.**
**A substance applied with a heat-shrink splice to reduce voltage stress.**
115
**What Is stress control tube.**
**A heat-shrink splice tube that reduces electrical stress to a safe level in a
trifurcating transitional splice.**
116
**What Is stress relief mastic.**
**A putty-like material that provides electrical stress relief to insulation, and
on PILC cables provides a barrier to oil on the paper tape. Sometimes called stress relief material.**
117
**What are stress relief material.**
**A type of tape that reduces voltage stress. Also stress relief mastic.**
118
**What Is strand shielding.**
**A conducting material applied over the surface of the stranded conductor making firm contact between the conductor and the insulation. It gives the stranded conductor the characteristics of a round conductor, thereby assisting in reducing the radial and tangential stresses. Semi-conducting tape is used for strand shielding.**
119
**What Is tangential stress.**
**Tangential means: tangent to the cross-section of the conductor. Differences in potential around the circumference of a conductor caused by voids between individual conduc- tors, can lead to arcing between conductors.**
120
**What Is tape splice**
**A splice that uses several layers of tape applied by hand.**
121
**What Is tape termination.**
**A termination that uses several layers of tape applied by hand.**
122
**What Is termination.**
**An assembly that connects the end of a cable to a piece of electrical equipment.**
123
**What Is thermoplastic.**
**A material that tends to lose its form when heated.**
124
**What Is thermoset.**
**A material that maintains its form when heated.**
125
**What Is tinning.**
**Coating a conductor with melted solder.**
126
**What Is tracking.**
**The process that produces tracks on the insulation as a result of the action of electric arcs. A failure occurs when the track extends sufficiently such that the track spans the distance
between two conductors.**
127
**What Is transitional splice.**
**A splice that joins two cables with different types of insulation.**
128
**What Is tracking resistance.**
**The ability of electrical insulation to resist the formation of a track. See tracking. The quantitative expression of tracking resistance is the time required to develop a track
spanning the distance between medium-voltage and ground electrodes.**
129
**What Is tracking-induced erosion.**
**The gradual wearing away of electrical insulation by the action of
electric arcs.**
130
**What Is tree (electrical).**
**Markings that look like a tree made by corona discharge within cable insulation
between
conductors.**
131
**What Is trifurcating splice.**
* *A splice that joins one three-conductor cable with three single-conductor
cables. **
132
**What Is trifurcating transitional splice.**
**A combination of the trifurcating splice and the transitional splice. Used to join cables with different designs or different types of insulations.**
133
**What Is URD.**
**underground residential distribution.**
134
**What Is underground residential distribution**
**Electrical service provided by an electric utility, under-
ground, between a distribution transformer and a residential customer's meter.**
135
**What Is varnished cambric tape.**
**An insulating tape made from cotton cambric (a fine, dense, light- weight fabric) which has been coated with yellow varnish.**
136
**What Is voltage.**
* *The potential difference between any two conductors, or between a conductor and
earth. AC voltages are typically measured as root-mean-square (RMS) values.**
137
**What Is voltage rating.**
* *The amount of voltage that can be applied across insulation without causing it to
fail. **
138
**What Is voltage stress.**
* *the voltage gradient applied across an insulator, usually with a harmful conno-
tation. The higher the voltage stress, the more likely that corona will occur at the edge of the insulator, causing the insulator to deteriorate over time, and eventually fail.**
139
**What Is vulcanize.**
**To treat rubber with sulfur and heat to make it more elastic, durable, and bondable
into a solid mass.**
140
**What Is withstand test.**
**A diagnostic test in which a voltage of a predetermined magnitude is applied for
a predetermined time period. If the test object survives the test it is deemed to have passed the
test.**
141
**What Is XLPE.**
**cross-linked polyethylene.**
142
**What Is Y splice.**
**branch splice.**
