Assignment 1 | InfoDotInc

Source text. Published from the recorded source PDF for NEETS Module 4: Electrical Conductors, Wire Techniques, and Schematic Reading.

Module 4-Electrical Conductors, Wiring Techniques, and Schematic Reading

UNCLASSIFIED

ASSIGNMENT 1

Textbook Assignment: Chapter 1, “Electrical Conductors,” pages 1-1 through 1-43.

Chapter 2 “Wiring Techniques,” pages 2-1 through 2-33.

1-1. Why has a "unit size" for conductors been established?

1. To compare the size and resistance of one conductor with that of another

2. To establish a uniform style for conductors

3. To determine the requirements for conductors

4. To ensure all conductors are interchangeable

1-2. What is the decimal equivalent of one (1) mil?

1. 1.000 in.

2. 0.100 in.

3. 0.010 in.

4. 0.001 in.

1-3. If a conductor has a diameter of 1/4 inch, what is its diameter in mils?

1. 250.0 mil

2. 25.0 mil

3. 2.50 mil

4. 0.250 mil

1-4. What is the definition of a mil foot?

1. A conductor .001 foot in length with a diameter of .001 millimeter

2. A conductor 1 foot in length with a diameter of .001 foot

3. A conductor 1 foot in length with a diameter of 1 mil

4. A conductor .001 foot in length with a diameter of .001 inch

1-5. A square mil is defined as the area of a square, the sides of which are each equal

in length to what dimension?

1. 1 mil-foot

2. 1 mil

3. 1.0 inch

4. .001 mil

Module 4-Electrical Conductors, Wiring Techniques, and Schematic Reading

UNCLASSIFIED

IN ANSWERING QUESTION 1-6, REFER TO FIGURE 1A.

1-6. What is the cross-section area of the illustrated rectangular bar conductor in

square mils?

1. 937,500,000 sq. mil

2. 3,750,000 sq. mil

3. 1,250,000 sq. mil

4. 187,500 sq. mil

1-7. A circular mil is defined as the area of a circle having what dimension?

1. A radius of 1 mil

2. A diameter of 1 mil

3. A circumference of 1 mil

4. A chord of 1 mil

1-8. If you have a 12-strand conductor and each strand has a radius (one half the

diameter) of 2/10 inch, what is the circular mil area of the conductor?

1. 1,920,000 cir. mil

2. 57,680 cir. mil

3. 48,000 cir. mil

4. 2,400 cir. mil

Figure 1A Rectangular Bar Conductor

Module 4-Electrical Conductors, Wiring Techniques, and Schematic Reading

UNCLASSIFIED

1-9. What is the square mil area for the conductor explained in question 1-8?

1. 244,344,097 sq. mil

2. 1,507,965 sq. mil

3. 61,115 sq. mil

4. 45,239 sq. mil

1-10. What is the definition of specific resistance?

1. The resistance of a length of conductor, at a given temperature, to voltage

2. The resistance of a cross-sectional area of a conductor, at a given

temperature, to the flow of current

3. The resistance of a unit volume of a substance to the flow of current

expressed in ohms

1-11. What factor(s) must be known to compute the resistance of a conductor?

1. The length of the conductor

2. The cross-sectional area of the conductor

3. The specific resistance of the substance of the conductor

4. Each of the above

Module 4-Electrical Conductors, Wiring Techniques, and Schematic Reading

UNCLASSIFIED

REFER TO THE FOLLOWING INFORMATION AND USE FIGURE 1B TO

ANSWER QUESTION 1-12. ASSUME THE TEMPERTURE TO BE 25º C AND YOU

HAVE TWO NEW COPPER CONDUCTORS TO RUN. RUN NO. 1 IS TO BE 2500

FEET LONG USING NO. 12 WIRE. RUN NO. 2 IS TO BE 6000 FEET LONG USING

NO. 7 WIRE.

1-12. What is the approximate total resistance of (a) Run No. 1 and (b) Run No. 2?

1. 9.72 ohms (b) 1.27 ohms

2. 4.68 ohms (b) 3.52 ohms

3. 4.05 ohms (b) 3.05 ohms

4. 1.12 ohms (b) 4.98 ohms

1-13. When a wire gauge is used to determine the size of a wire, the measurement

should be made in what part of the gauge?

1. In the slot

2. In the semicircular opening

3. Either 1 or 2 above, depending on wire size

Figure 1B

Module 4-Electrical Conductors, Wiring Techniques, and Schematic Reading

UNCLASSIFIED

IN ANSWERING QUESTION 1-14, REFER TO FIGURE 1C.

1-14. Which of the following factors is used to determine the current rating of a wire?

1. B, C, E, and G

2. A, D, E, and G

3. B, D, E, and F

4. A, B, E, and F

1-15. What types of insulation are best suited for use in a high-temperature

environment?

1. Cotton, polytetrafluoroethylene, and oiled paper

2. FEP, silicone rubber, and extruded polytetrafluoroethylene

3. Oiled paper, FEP, and rubber

4. Rubber, polytetrafluoroethylene, and silk

1-16. What is the "ambient" temperature of a conductor?

1. It is the normal temperature of a conductor through which current is

flowing

2. It is the heat generated by external sources and affecting a conductor’s

temperature

3. It is the maximum heat a conductor can withstand according to its current

rating

4. It is the temperature at which the insulation of a conductor begins to break

down

Figure 1C

Module 4-Electrical Conductors, Wiring Techniques, and Schematic Reading

UNCLASSIFIED

1-17. Which of the following metals is the best conductor of current?

1. Aluminum

2. Copper

3. Silver

4. Manganin

FIGURE 1D LISTS SOME OF THE ADVANTAGES AND DISADVANTAGES OF

VARIOUS CONDUCTORS. IN ANSWERING QUESTIONS 1-18 AND 1-19, REFER

TO FIGURE 1D.

1-18. When electricity is carried over long distances, which of the following are

advantages for using aluminum as the conductor as opposed to copper?

1. B and C

2. D and E

3. C and I

4. E and G

1-19. Which of the following are advantages for using copper as the conductor as

opposed to aluminum?

1. B, D, and I

2. C, E, and G

3. B, E, and H

4. A, F, and I

Figure 1D

Module 4-Electrical Conductors, Wiring Techniques, and Schematic Reading

UNCLASSIFIED

1-20. Because its resistance changes very little with temperature changes, what

conductor is best suited for use in measuring instruments?

1. Copper

2. Aluminum

3. Manganin

4. Silver

1-21. If a 75-ohm sample of copper wire at 0º C is heated to 30º C, what is the

approximate total resistance? (The temperature coefficient of resistance of copper

at 0º C is 0.00427).

1. 0.32 ohm

2. 9.61 ohms

3. 65.39 ohms

4. 84.61 ohms

1-22. What definition best describes an insulating material?

1. A material that has a very high resistance

2. A material that has a very low resistance

3. A material that has a very high conductivity

4. A material that has a very low dielectric strength

1-23. The dielectric strength of an insulating material is a measurement of the material's

ability to resist electrostatic stress caused by what factor?

1. Resistance

2. Current

3. Voltage

4. Chafing or friction

1-24. Insulation resistance can best be defined as the ability of an insulating material to

resist what action?

1. Current leakage

2. Electrostatic stress

3. Breakdown by voltage

4. External factors acting upon the conductor

Module 4-Electrical Conductors, Wiring Techniques, and Schematic Reading

UNCLASSIFIED

1-25. For a material to be a good insulator, what two properties are most important?

1. High dielectric strength and low insulation resistance

2. High dielectric strength and high insulation resistance

3. Low dielectric strength and high insulation resistance

4. Low dielectric strength and low insulation resistance

1-26. When rubber is used as the insulating material over a copper conductor, why is a

thin coating of tin used between the two materials?

1. To decrease the electrostatic stress

2. To increase the insulation resistance of the rubber

3. To prevent a chemical action from taking place between the copper and

rubber

4. To reduce the amount of insulating material required.

1-27. What is the NEC for a rubber heat-resistance compound?

1. RHH

2. RWH

3. RTW

4. RWT

1-28. Latex rubber is a high-grade compound consisting of what percentage of unmilled

grainless rubber?

1. 70%

2. 80%

3. 90%

4. 95%

1-29. Plastic insulation is normally used for what levels of voltage?

1. Very high to high

2. High to medium

3. Medium to low

4. Low to very low

1-30. When dealing with NEC type designators for thermoplastics, the letter "W" stands

for what type of insulation?

1. Oil-resistant

2. Moisture-resistant

3. Heat-resistant

4. Asbestos

Module 4-Electrical Conductors, Wiring Techniques, and Schematic Reading

UNCLASSIFIED

1-31. When you work on synthetic insulated wiring, what safety precaution must be

observed?

1. Wear protective goggles at all times

2. Avoid breathing the vapors when the insulation is heated

3. Wear a dust mask in confined spaces

4. Wear protective gloves if there are cuts or abrasions on your hands

1-32. What nonmetallic material is most commonly used to protect wires and cables?

1. Rubber

2. Jute and asphalt covering

3. Fibrous tape

4. Fibrous braid

1-33. What is the common name for woven covers?

1. Yarn

2. Loom

3. Fibrous tape

4. Unspun felted cotton

1-34. What percentage of tin is used in alloy-lead sheathing?

1. 6%

2. 2%

3. 8%

4. 4%

1-35. Why is the use of asbestos being discontinued as an insulating material in the

Navy?

1. It breaks down rapidly with continued use

2. It is not as effective as other types of insulation

3. It has not proven suitable for a shipboard environment

4. It poses a health hazard to personnel

1-36. What happens to asbestos insulation when it gets wet?

1. Its insulation resistance becomes too high

2. It emits dangerous fumes

3. It acquires too great a dielectric strength

4. It becomes a conductor

Module 4-Electrical Conductors, Wiring Techniques, and Schematic Reading

UNCLASSIFIED

1-37. What insulating materials are best suited for use with high voltage?

1. Thermoplastic and rubber

2. Varnished cambric and oil impregnated paper

3. Teflon and silk

4. Silk and cotton

1-38. What is the common name for enamel-insulated wire?

1. Winding wire

2. Motor wire

3. Magnet wire

4. Coil wire

1-39. What types of conductor protection are normally used for shipboard wiring?

1. Wire braid armor and nonmagnetic steel tape

2. Lead cable and Jute

3. Jute and nonmagnetic steel tape

4. Lead sheathing and rubberized tape

1-40. What are the basic requirements for a splice or terminal connection?

1. To be mechanically and electrically effective

2. To be preinsulated and nonconductive

3. To have minimum cost and maximum efficiency

4. To have circuit continuity and minimum cost

1-41. The preferred method for removing insulation from most types of insulated wire

is by using what tool?

1. Razor blade

2. Electrician’s pliers

3. Wire stripper

4. Knife

1-42. When a wire is insulated with glass braid or asbestos and requires stripping,

which of the following tools should NOT be used?

1. Knife

2. Rotary wire stripper

3. Hand wire stripper

4. Hot-blade wire stripper

Module 4-Electrical Conductors, Wiring Techniques, and Schematic Reading

UNCLASSIFIED

1-43. What is the preferred tool to use to strip aluminum wire?

1. Knife

2. Rotary wire stripper

3. Hand wire stripper

4. Hot-blade wire stripper

1-44. When a Western Union splice is used to connect two wires, why should the

twisted ends of the wires be pressed down as close as possible to the straight

portion of the wire?

1. To increase the strength of the splice

2. To prevent the wires from puncturing the tape covering

3. To minimize the resistance change in the circuit

4. To increase the dielectric strength of the insulation

1-45. When multiconductor cables are spliced, why are the splices staggered?

1. To prevent possible shorting between conductors

2. To increase the strength of the individual splices

3. To decrease insulated resistance

4. To reduce the overall size of the joint

1-46. When is a rattail joint normally used?

1. When a branch circuit is required and a junction box is used to join

conduit

2. When a Western Union splice would be too bulky

3. When asbestos or glass braid is used as insulation

4. When the branch wire will be subjected to a heavy strain

1-47. If a fluorescent light is to be attached to a branch circuit, which of the following

splices should normally be used?

1. Staggered splice

2. Knotted tap joint

3. Western Union splice

4. Fixture joint

Module 4-Electrical Conductors, Wiring Techniques, and Schematic Reading

UNCLASSIFIED

1-48. When is a knotted tap joint normally used?

1. When a branch circuit is joined to a continuous wire (main wire)

2. When a Western Union splice would be too bulky

3. When a lighting fixture is joined to a branch circuit

4. When a wire nut is used to complete the joint

1-49. Which of the following splices is NOT butted?

1. Fixture joint

2. Rattail joint

3. Knotted tap joint

4. Western Union splice

1-50. Why is friction tape used over a splice?

1. To provide a protective covering over the rubber tape

2. To provide maximum insulation to the splice

3. To prevent shock when latex rubber is used

4. To reduce the amount of rubber tape required

1-51. Why would you use a crimped terminal instead of a soldered terminal?

1. Connections can be made more rapidly

2. Less operator skill is required

3. Connections are more uniform in construction

4. Each of the above

1-52. When noninsulated splices and terminal lugs are insulated, what types of

insulation are most commonly used?

1. Rubber tape and friction tape

2. Spaghetti and heat-shrinkable tubing

3. Spaghetti and friction tape

4. Rubber tape and heat shrinkable tubing

1-53. When heat-shrinkable tubing is used, what is the maximum temperature to which

the wire should be subjected?

1. 180ºF

2. 220ºF

3. 300ºF

4. 340ºF

Module 4-Electrical Conductors, Wiring Techniques, and Schematic Reading

UNCLASSIFIED

1-54. When a large aluminum terminal lug or splice is installed, why is it NOT

necessary to clean the aluminum wire?

1. It is done automatically by the tubing

2. The wire is cleaned by the abrasive compound in the lug or splice

3. Oxide film does not form on aluminum

4. The insulation used provides the necessary cleaning agent

1-55. When aluminum terminals lugs or splices are installed, which of the following

tools is generally recommended for use?

1. Pliers

2. Power crimping tool

3. Hand crimping tool

4. Vise grips

1-56. Why is a lockwasher NOT used with an aluminum terminal?

1. The washer will reduce conductivity at the terminal

2. The washer will gouge the lug and cause deterioration

3. The washer will set up a corrosive action between dissimilar metals

4. The washer will increase resistance and heat causing eventual failure

1-57. The most common method of terminating and splicing wires is by using

preinsulated terminal lugs and splices.

1. True

2. False

1-58. Which of the following is an advantage of using preinsulated splices and terminal

lugs?

1. Heat shrinkable tubing is not required

2. Spaghetti is not required

3. They offer extra supporting strength to the wire insulation

4. Each of the above

Module 4-Electrical Conductors, Wiring Techniques, and Schematic Reading

UNCLASSIFIED

1-59. Color codes are used on preinsulated terminal lugs and splices to indicate what

information?

1. The resistance, in ohms, of the lugs and splices

2. The style of crimping tool to be used

3. The type of circuit in which they are to be used

4. The wire sizes on which they are to be used