2-5-1 Flashcards
The manufacturing of cable in the field under adverse conditions without the use of modern manufacturing equipment or quality control testing is the definition of __?__.
cable splicing
The National Electrical Codes’ definition of medium voltage ranges from __?__ to __?__.
2,001-35,000 volts
From a technical standpoint, one factor that influences the choice of a cable is it will be subjected to special conditions such as the presence of corrosive materials.
true
Factors that influence the choice of a cable include its __?__ and its current or kVA loading capabilities.
voltage rating
From a technical standpoint, heating conditions that influence the choice of cable include the ambient temperature, proximity of other cable, adjacent heat sources, and the thermal conductivity of the soil it will be buried in.
true
The principal factors to be considered in the selection of conductors include materials, flexibility, size (current carrying capacity), and its __?__.
shape
The advantages of using a cable with a compact sector -shaped conductor are its smaller diameter, low reactance, and a(n) __?__.
low voltage drop
The most common shape of conductor used with medium voltage cables today is the __?__ conductor.
concentric round
The purpose of applying strand shielding between the conductor and the insulation of the cable is to eliminate __?__ in air voids at the interstices between the conductor and the cable insulation.
voltage stess
A compact round conductor is more flexible than a concentric round conductor.
false
The type of cable insulation that offers excellent resistance to ozone and weathering, has good low temperature properties, good heat resistant properties, and excellent electrical properties is the __?__ type of insulations.
EP
On cable circuits where the clearing time requirements of the 100% level category cannot be met and there is adequate assurance the faulted section will be de-energized in a time not exceeding one hour, cable with __?__ insulation level should be used.
133%
An increase of __?__ AWG numbers will approximately double the diameter of the cable.
6
One function of an insulation shield is to confine the dielectric field within the cable.
true
A tape consisting of carbon-black or lamp-black impregnated in a material such as cloth, rubber, or neoprene, and applied directly over the insulation of the shielded conductors is called __?__ tape.
semi conducting
Insulation shielding of medium voltage cable helps prevent high stress and __?__ by distributing the stress evenly throughout the entire insulation structure.
possible corona
A luminous hair-like (curved or bent) arc discharge resulting from a partial electric breakdown. This describes the electrical discharge called __?__ as applied to medium voltage power cable.
corona
The jacketing over a medium voltage cable provides both mechanical and environmental protection for the cable. Four types of material used for cable jacket include fibrous, rubber and rubber-like, thermoplastic, and __?__ sheathing.
metallic
The dielectric constant of butyl rubber is __?__.
3.7
One reason for using concentric neutral cables is that the bare neutral helps clear faults more rapidly.
true
Insulation types come in PILC (Paper Insulated Lead Covered), EPR (Ethylene Propylene Rubber), and __?__ (Cross-Linked Polyethylene).
XLPE
Medium voltage cables utilize copper, aluminum, and silver as conductor material.
false
A __?__ shield is placed over the insulation shield. This shield serves as a path for the return current (neutral).
metallic
When moisture fills the very fine electric stress lines that occur at voids and other insulation irregularities on a cable and spread towards the outer edge, this is known as __?__.
water treeing of the insulation
Because of different types of splicing and terminating methods, it is important the cable splicer follow the manufacturer’s or __?__ specifications to the letter. Failure to do so may lead to cable failure.
owners
