Cable 101
Exam Answers
1. The most common conductor material used in electronic cable is:
A. CopperB. Copper covered steel
C. Aluminum
D. Copper alloy
2. The conductivity of copper is:
A. 18%
B. 45%
C. Approximately 85%
D. 100%
3. The most common type of stranding used in electronic wire & cable products is:
C. UnilayA. Bunch
B. Rope Lay
D. Unistrand
4. Most Belden conductors are tinned because:
A. It helps prevent oxidation.
B. It reduces conductor cost by 15%.
C. It makes crimp termination easier.
D. It makes the conductor more suited to high frequency applications.
5. Conductors can be made more flexible by:
B. Increasing the number of strands.A. Using a thinner insulation.
C. Silver coating.
D. Lengthening the length of lay.
6. The most common conductor for fixed applications is:
A. Solid
B. 7 strand
C. 10 strand
D. 16 strand
7. Copper covered steel conductors:
A. Are stronger than copper.
B. Have better conductivity than copper at RF.
C. Are not used in Broadband/CATV cables.
D. Are used only in non-NEC cables.
8. The advantages of a stranded over a solid conductor:
A. Longer flex life.
B. Less costly.
C. Less flexibility.
D. Improved strength.
9. MATCH (2 points)
C____Flex Life ____
Stranding ____
D____Lay ____
E____Flexibility ____
A____Skin Effect ____
B____A. The ease with which a conductor can be bent.
B. As the frequency increases, the flow of electrons is limited to the surface of the conductor.
C. A measure of the ability of the conductor to bend repeatedly without breaking.
D. Twisting a group of wires to form a single conductor.
E. The distance required for one strand to complete one revolution about the strand which it is cabled.
10. The primary purpose(s) of the shield is/are:
D. Both A and B.A. To contain electrical energy.
B. Protection from external interference.
C. Color coding.
11. The shield material chosen is determined by:
D. All of the above.A. Required shield effectiveness.
B. Mechanical strength.
C. Cost
12. The advantages of the Beldfoil shield are:
D. 100% coverage.A. Low frequency shield effectiveness.
B. Tensile strength.
C. Physical strength.
13. Belden’s shorting fold:
A. Eliminates the escape of energy through the slot.
B. Is isolated from the drain wire.
C. Degrades shield performance.
D. Eliminates metal to metal contact.
14. The Duofoil shield:
B. Improves shield reliability and effectiveness.A. Has an extra layer of polyester.
C. Reduces flex life.
D. Is more effective at low frequencies.
15. Braid shields:
A. Can be copper or aluminum.
B. Provide marginal flex life.
C. Are effective at high frequencies.
D. Provide 100% coverage.
16. Braid shields, when compared to foil shields, are:
C. Stronger, mechanically.A. Lighter weight.
B. Easier to terminate.
D. Lower cost.
17. MATCH (2 points)
C_____Drain Wire ____
Shield ____
A_____Braid ____
E_____Crosstalk ____
D_____Beldfoil ____
B_____A. Contains electrical energy.
B. Mylar and aluminum.
C. Eases termination.
D. Transfer of energy from one cable member to another.
E. One set of strands is applied clockwise, the other counter clockwise.
18. Thermoplastic materials:
D. Both A and C.A. Include PVC, Polyethylene, and FEP.
B. Will not melt at high temperatures.
C. Are most popular in cable constructions.
E. All of the above.
19. Thermoset materials have advantages that include:
C. Excellent low temperature characteristics.A. Easier to color than thermoplastic materials.
B. Will melt at high temperatures.
D. Tend to kink and curl.
E. Both A and C.
20. The primary purpose of the jacket is:
A. Protection from the environment.
B. To isolate the conductors, electrically and physically, within a cable.
C. Protection from external interference.
D. Protection from crosstalk.
21. Polyethylene:
D. All of the above.A. Excellent moisture resistance.
B. Very good dielectric properties.
C. Used in direct burial.
22. PVC:
C. Has a variety of formulations.A. Rarely used for cable insulations.
B. Poor flame and water resistance.
D. Is difficult to color.
23. Polyurethane is:
A. Used in highly abrasive environments.
B. A thermoset material.
C. Very flame retardant.
D. Used as coaxial cable insulation material.
24. FEP has many outstanding advantages including:
A. Low flame spread.
B. Low cost.
C. High elongation.
D. All of above.
25. Dielectric strength is:
B. The material’s ability to withstand voltage breakdown.A. The determining factor for capacitance, impedance, and relative performance.
C. The maximum voltage allowed by UL to be applied.
D. The physical breaking strength of the insulation material.
26. Neoprene:
D. All of the above.A. Similar to rubber characteristics.
B. Good oil and ozone resistance.
C. Has good aging characteristics.
27. Lower dielectric constant means:
D. All of the above.A. Low attenuation.
B. Low capacitance.
C. High velocity of propagation.
28. Solid insulation is:
A. Most common.
B. Has air voids.
C. Difficult to apply.
D. Used to reduce the dielectric constant.
29. Cellular or foamed insulations are:
D. Used to reduce the dielectric constant.A. Most common.
B. Have no air voids.
C. Easy to apply.
30. MATCH ( 2 points)
D_____Temperature rating ____
Velocity of propagation ____
G_____Capacitance ____
A_____Tensile strength ____
F_____Attenuation ____
B_____Elongation ____
E_____Dielectric strength ____
C_____A. A measure, expressed in picofarads per foot, of the material’s ability to store electrical energy.
B. A measure, expressed in decibels per 100 feet, of the cable’s loss of electrical energy.
C. The insulation’s ability to contain or withstand voltage without breaking down.
D. The range of temperatures at which a material can be used without degradation.
E. How far an insulation will stretch before it breaks.
F. The amount of force, measured in pounds per square inch, that it takes to break an insulation.
G. Expressed as a percentage, the transmission speed of an electrical signal down a length of a cable compared to its speed in free air, which is also the speed of light.