Flashcards in NAVEDTRA 14176A, NEETS Mod. 4, Ch. 1 Deck (43)
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1
Which unit of measurement is used to determine the cross-sectional area of a square or rectangular conductor?
Square mil
2
What is the standard unit of measurement of a round wire cross-sectional area?
Circular mil
3
What can be done to increase the flexibility of wire?
Stranding
4
What is a heavy copper strap or bar that is used to connect several circuits together?
Bus bar
5
What is the resistance in ohms offered by a unit volume (the circular-mil-foot or the centimeter cube) of a substance to the flow of electric current?
Specific resistance
6
What is the reciprocal of conductivity?
Resistivity
7
What is the most common method of measuring wire size in the Navy?
American Wire Gauge (AWG)
8
What is a single slender rod or filament of drawn metal called?
Wire
9
Which type of wire is suitable for carrying an electric current?
Conductor
10
Which type of conductor is composed of a group of wires or of any combination of groups of wires?
Stranded
11
Which wire property is used to determine what size is needed for a given load, or current drain?
Current rating
12
What prepares tables showing the safe current ratings for sizes and types of conductors covered with various types of insulation?
National Board of Fire Underwriters
13
What is the best conductor?
Silver
14
What are the two most commonly used conductors?
Copper and Aluminum
15
Only about what percent of the conductivity of copper does aluminum have?
60
16
What is the discharge of electricity from the wire when it has a high potential called?
Corona
17
What are generally referred to as "insulators" or "insulating material."?
Nonconductors
18
Insulation resistance along with what else are the two fundamental properties of insulating materials?
Dielectric strength
19
What is the resistance to current leakage through the insulation materials called?
Insulation resistance
20
What can insulation resistance be measured with that wont damage the insulation?
Megger
21
What is the ability of an insulator to withstand potential difference?
Dielectric strength
22
What is normally used for low- or medium-range voltage?
Rubber insulation
23
Which standard has the National Electrical Code (NEC) adopted as the minimum requirements for rubber insulation as specified by Underwriters' Laboratories?
Code-graded rubber
24
Latex rubber is a high-grade compound consisting of what percent of unmilled grainless rubber?
90
25
Which rubber compound does not carry the "R" designator for many of its applications?
Silicone
26
What is one of the most common types of plastic insulating materials?
Thermoplastic
27
What is cotton cloth that has been coated with an insulating varnish known as?
Varnished cambric
28
Varnished cambric and paper insulation for cables are the two types of insulating materials most widely used at voltages above how many volts?
15,000
29
What is a high-temperature insulation used extensively in aircraft and equipment installations?
Extruded polytetrafluoroethylene
30
