Chapter 6 Conductors 101 Copyright Goodheart-Willcox Co., Inc. Copyright Goodheart-Willcox Co., Inc. Review Questions Answer the following questions using the informa- tion provided in this chapter. 1. List three permitted uses of bare conductors. 2. What is the advantage of stranded conductors over solid conductors? 3. List three conditions that must be met when running conductors in parallel. 4. Name three markings that are required to appear on conductors or cables in addition to the maximum rated voltage. 5. What is the most infl factor fluential contributing to voltage drop? 6. Describe two ways of decreasing the voltage drop in a circuit. 7. Explain what an insulated cable with “XHHW” marking indicates. 8. What does the designation AWG stand for? 9. What are the three categories of flexible fl cords? 10. How does temperature affect conductors? 11. What is the minimum allowable conductor size for elevator control and signaling circuits? 12. A conduit contains two conductors. What percentage of the total conduit area can the conductors occupy? Know the Code Refer to the National Electrical Code to answer the following questions. 1. Using Table 8, Chapter 9 of the Code, fi nd the area of a solid 8 AWG copper fi conductor. 2. What size rigid metal conduit is required for a feeder circuit consisting of four 8 AWG and two 10 AWG THW conductors? 3. A piece of equipment is supplied with 20-amp, 120-volt, single-phase power by solid, uncoated 12 AWG copper conductors. The conductors travel a length of 110′. Calculate the voltage drop. Determine voltage drop as a percent of total voltage. 4. For what application is conductor type SIS used? 5. In which wire sizes is conductor type UF available? 6. What is the nominal insulation thickness on a 6 AWG conductor in a portable power cable (type of flexible cable)? fl 7. Two copper type THHW conductors are being designed to supply 30 amps through EMT with an ambient temperature of 86°F. What size conductors should be used? 8. A run of rigid metal conduit in an 86°F area will contain fi ve aluminum type fi XHHW conductors. If the conductors supply 22 amps, what size conductors should be used? 9. What is the allowable ampacity of a 2/0 AWG copper-clad aluminum type RH conductor in an area with an ambient temperature of 135°F? 10. Twelve 14 AWG copper type THW conductors are located within a raceway. If all the conductors carry current, what is the allowable ampacity of each conductor? 11. What is the allowable ampacity of five fi 4 AWG copper FEP conductors in a raceway surrounded by 210°F air? 12. The one-way length of a single-phase, 15-amp circuit is 220′. Determine the voltage drop if the conductors are stranded, uncoated 12 AWG aluminum. What is the percentage voltage drop if it is a 120-volt circuit? 13. What size PVC conduit (Schedule 40) is needed to contain three 1/0 AWG RHW conductors?
Modern Commercial Wiring, 7th Edition Page 101 (115 of 315)
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Chapter 6 Conductors 101 Copyright Goodheart-Willcox Co., Inc. Copyright Goodheart-Willcox Co., Inc. Review Questions Answer the following questions using the informa- tion provided in this chapter. 1. List three permitted uses of bare conductors. 2. What is the advantage of stranded conductors over solid conductors? 3. List three conditions that must be met when running conductors in parallel. 4. Name three markings that are required to appear on conductors or cables in addition to the maximum rated voltage. 5. What is the most infl factor fluential contributing to voltage drop? 6. Describe two ways of decreasing the voltage drop in a circuit. 7. Explain what an insulated cable with “XHHW” marking indicates. 8. What does the designation AWG stand for? 9. What are the three categories of flexible fl cords? 10. How does temperature affect conductors? 11. What is the minimum allowable conductor size for elevator control and signaling circuits? 12. A conduit contains two conductors. What percentage of the total conduit area can the conductors occupy? Know the Code Refer to the National Electrical Code to answer the following questions. 1. Using Table 8, Chapter 9 of the Code, fi nd the area of a solid 8 AWG copper fi conductor. 2. What size rigid metal conduit is required for a feeder circuit consisting of four 8 AWG and two 10 AWG THW conductors? 3. A piece of equipment is supplied with 20-amp, 120-volt, single-phase power by solid, uncoated 12 AWG copper conductors. The conductors travel a length of 110′. Calculate the voltage drop. Determine voltage drop as a percent of total voltage. 4. For what application is conductor type SIS used? 5. In which wire sizes is conductor type UF available? 6. What is the nominal insulation thickness on a 6 AWG conductor in a portable power cable (type of flexible cable)? fl 7. Two copper type THHW conductors are being designed to supply 30 amps through EMT with an ambient temperature of 86°F. What size conductors should be used? 8. A run of rigid metal conduit in an 86°F area will contain fi ve aluminum type fi XHHW conductors. If the conductors supply 22 amps, what size conductors should be used? 9. What is the allowable ampacity of a 2/0 AWG copper-clad aluminum type RH conductor in an area with an ambient temperature of 135°F? 10. Twelve 14 AWG copper type THW conductors are located within a raceway. If all the conductors carry current, what is the allowable ampacity of each conductor? 11. What is the allowable ampacity of five fi 4 AWG copper FEP conductors in a raceway surrounded by 210°F air? 12. The one-way length of a single-phase, 15-amp circuit is 220′. Determine the voltage drop if the conductors are stranded, uncoated 12 AWG aluminum. What is the percentage voltage drop if it is a 120-volt circuit? 13. What size PVC conduit (Schedule 40) is needed to contain three 1/0 AWG RHW conductors?
