2. Master Examination Practice Drill #3 2011

3. O 1. Given: Two (2) rigid metal conduits (RMC) are to support a weatherproof 18 cu. In. device box, with threaded hubs, which contains a 125-volt, 20-ampere receptacle outlet. The conduits are to be threaded wrench tight into the hubs and, in general, shall be secured with at LEAST _____ of the enclosure. A. 8 inches B. 12 inches C. 18 inches D. 24 inches

4. QuestionAnswerReferenceNEC PG. # 1.C314.23(F)181

5. O 2. In general, if the cablebus system is rated 95 amperes, the MAXIMUM allowable rating of the overcurrent device used to protect the cablebus is _______. A. 80 amperes B. 90 amperes C. 95 amperes D. 100 amperes

6. QuestionAnswerReferenceNEC PG. # 2.D370.5227 240.4(B)(2)&(3)90 240.6(A)91

7. O 3. A twenty-five (25) ft. long tap conductor tapped from a 100 ampere rated feeder conductor, shall have an ampacity of NOT less than ________. A. 50 amperes B. 75 amperes C. 25 amperes D. 33.3 amperes

8. QuestionAnswerReferenceNEC PG. # 3.D240.21(B)&(B)(2)(1)92&93 100 amperes/3 = 33.3 amperes

9. O 4. Disregarding exceptions, bonding between Class I locations and the point of grounding for service equipment may be done by _________. A. Double locknuts B. Bonding jumpers C. Insulated bushings D. Metal raceways

10. QuestionAnswerReferenceNEC PG. # 4.B501.30(A)381

11. O 5. Determine the demand load, in VA, on the ungrounded service-entrance conductors, for the general-lighting and receptacles for a 25,000 sq. ft. office building that has one hundred-fifty (150) general-purpose duplex receptacles. Consider the service overcurrent protection device is NOT listed for continuous use. A. 112,075 VA B. 106,000 VA C. 90,200 VA D. 127,875 VA

12. QuestionAnswerReferenceNEC PG. # 5.DTbl. 220.1263 220.14(I)63 220.4464 Tbl. 220.4464 Art. 10027 230.42(A)(1)82 25,000 sq. ft. x 3.5 VA x 125% (lighting) = 109,375 VA 150 receptacles x 180 VA each = 27,000VA 1 st 10,000 VA @ 100% = 10,000 VA 27,000 VA – 10,000 VA = 17,000 VA @ 50% = 8,500VA Total = 127,875 VA

13. O 6. When an electrical service is required to have a grounded conductor present, what is the smallest grounded conductor permitted for an electric service using size 1000 kcmil copper undergrounded (phase) conductors? A. 3/0 AWG copper B. 2/0 AWG copper C. 1/0 AWG copper D. 4/0 AWG copper

14. QuestionAnswerReferenceNEC PG. # 6.B250.24(C)(1)105 Tbl. 250.66115

15. O 7. Determine the MINIMUM number of 20- ampere, 277-volt, general-lighting branch circuits required for a 150,000 sq. ft. department store, when the actual connected lighting load is 400 kVA, A. 72 branch circuits B. 82 branch circuits C. 91 branch circuits D. 102 branch circuits

16. QuestionAnswerReferenceNEC PG. # 7.C210.19(A)91)52 210.11(B)51 400 kVA = 400,000 VA x 125% (continuous load) = 500,000 VA (bldg.) 277 volts x 20 amperes = 5540 VA (one circuit) 500,000 VA. (bldg. lighting) 5,540 VA (one circuit) = 90.2 = 91 circuits *NOTE – Circuits need only to be installed to service the connected load.

17. O 8. Where a two-gang box contains two (2) single-pole switches, unless the box is equipped with permanently installed barriers, the voltage between the switches shall NOT be in excess of _______. A. 120 volts B. 277 volts C. 240 volts D. 300 volts

18. QuestionAnswerReferenceNEC PG. # 8.D404.8(B)268

19. O 9. An aluminum grounding electrode shall be _________. A. Installed at least 18 inches above the earth B. Installed at least 24 inches above the earth C. In direct earth burial D. Prohibited

20. QuestionAnswerReferenceNEC PG. # 9.D250.52(B)(2)112

21. O 10. A panelboard is limited to 42 overcurrent protective devices where ________. A. The panelboard is a power panelboard B. The panelboard is a “split-bus” type panelboard C. The panelboard supplies lighting branch-circuits only D. One is installed

22. QuestionAnswerReferenceNEC PG. # 10.B408.36, Ex. 2276

23. O 11. When rigid polyvinyl chloride conduit (PVC) is used to enclose conductors feeding a wet-niche luminaire in a permanently installed swimming pool, a ______ insulated copper grounding conductor shall be installed in this conduit, unless a listed low- voltage lighting system not requiring grounding is used. A. 12 AWG B. 10 AWG C. 8 AWG D. 6 AWG

24. QuestionAnswerReferenceNEC PG. # 11.C680.23(B)(2)(b)581

25. O 12. In general, what is the largest size transformer, in kVA, that may be installed in an area or room that is NOT constucted in a fire-resistant manner? A. 75 KVA B. 112 ½ KVA C. 150 KVA D. 50 KVA

26. QuestionAnswerReferenceNEC PG. # 12.B450.21(B)352

27. O 13. When calculating the total load of an office building, and the number of general- purpose receptacles to be installed is not yet determined, an additional load of _____ volt- amp(s) per square foot is required for the receptacle outlets. A. One B. Two C. One-Half D. Three

28. QuestionAnswerReferenceNEC PG. # 13.A220.14(K)(2)63

29. O 14. When sizing time-delay Class CC fuses for motor branch-circuit, short-circuit and ground-fault protection, they are to be sized at the same value as ________. A. inverse-time circuit breakers B. Nontime-delay fuses C. Instantaneous trip circuit breakers D. Adjustable trip circuit breakers

30. QuestionAnswerReferenceNEC PG. # 14.BTbl. 430.52, Note 1323

31. O 15. Conductors other than service-entrance conductors shall be permitted to be installed in a cable tray with service-entrance conductors provided __________. A. A solid fixed barrier of material compatible with the cable tray is installed to separate the systems B. The conductors are not in excess of 480 volts to ground C. The voltage between the conductors is not in excess of 600 volts D. The conductors have equal insulation and temperature ratings

32. QuestionAnswerReferenceNEC PG. # 15.A203.44, Ex82

33. O 16 The MAXIMUM allowable ampacity of a size 750 kcmil XHHW aluminum conductor where there are six (6) current-carrying conductors in the raceway, installed in a dry location, where the ambient temperature will reach 22°C is ________ A. 323.40 amperes B. 365.40 amperes C. 361.92 amperes D. 348.00 amperes

34. QuestionAnswerReferenceNEC PG. # 16.CTbl. 310.15(B)(16)154 Tbl. 310.15(B)(2)(a)150 Tbl. 310.15(B)(3)(a)152 Size 750 kcmil AL ampacity (before derating) = 435 amperes 435 amps x 1.04 (temp correction) x.8 (adj. factor) = 361.92 amperes

35. O 17. In which of the following locations is a cable tray prohibited to be installed? A. Basement B. Storage Rooms C. Sealed Ceiling Spaces D. When Passing Through a Wall

36. QuestionAnswerReferenceNEC PG. # 17.C392.18 (D)&(E)240

37. O 18. What is the MINIMUM size copper common grounding electrode conductor required to run through a building to four (4) separately derived systems (transformers) each having size 3/0 AWG copper secondary conductors. A. 4 AWG B. 2 AWG C. 3/0 AWG D. 8 AWG

38. QuestionAnswerReferenceNEC PG. # 18.C250.30(A)(6)(a)(1)108

39. O 19. Where a commercial building has a 600 ampere, 3-phase, 208Y/120 volt service supplied with two (2) paralled sets of size 350 kcmil copper conductors installed in separate raceways, determine the MINIMUM size aluminum grounding electrode conductor permitted to the metal water piping system used as the grounding electrod. A. 250 kcmil B. 4/0 AWG C. 3/0 AWG D. 2/0 AWG

40. QuestionAnswerReferenceNEC PG. # 19.B250.66115 Tbl. 250.66115 350 kcmil x 2 conductors = 750 kcmil *NOTE – A size 4/0 AWG aluminum grounding electrode conductor should be selected

41. O 20. The NEC permits trade size 3/8 in. flexible metal conduit (FMC) to be used to enclose tap conductors for luminaires, provided the length of the FMC does NOT exceed __________. A. 4 feet B. 6 feet C. 8 feet D. 10 feet

42. QuestionAnswerReferenceNEC PG. # 20.B348.20(A)(2)c.206

43. O 21. What is the MAXIMUM distance allowed to support intermediate metal conduit (IMC) from a junction box, where structural members do not readily permit fastening? A. 3 feet B. 5 feet C. 6 feet D. 8 feet

44. QuestionAnswerReferenceNEC PG. # 21.B342.30(A)(2)203

45. O 22. All of the following listed copper conductors are to be installed in an electrical metallic tubing (EMT) that is in excess of 24 inches long.  24-size 10 AWG with TW insulation  10-size 10 AWG with THW insulation  14-size 12 AWG with THHN insulation Determine the MINIMUM trade size of EMT required. A. 2 in. B. 2 ½ in. C. 3 in. D. 3 ½ in.

46. QuestionAnswerReferenceNEC PG. # 22.AChpt. 9, Tbl. 5717&718 Chpt. 9, Tbl. 4712 Size 10 AWG TW =.0243 sq. in. x 24 =.5832 sq. in. Size 10 AWG THW =.0243 sq. in. x 10 =.2430 sq. in. Size 12 AWG THNN =.0133 sq. in. x 14 =.1862 sq. in. TOTAL = 1.1024 sq. in. *NOTE – Trade size 2 inch EMT with a permitted fill of 1.342 sq. in. @ 40% should be selected

47. O 23. When combination surface nonmetallic raceways are used both for signaling and for power and lighting circuits, the different systems shall be ________. A. Prohibited B. Run in the same compartment C. Separated by at least ½ in. D. Run in separate compartments

48. QuestionAnswerReferenceNEC PG. # 23.D388.70238

49. O 24. When sizing fuses for a branch circuit serving a hermetic refrigerant motor- compressor, the device shall NOT exceed ____ of the rated load current marked on the nameplate of the equipment. A. 115 percent B. 125 percent C. 175 percent D. 225 percent

50. QuestionAnswerReferenceNEC PG. # 24.D440.22(A)343

51. O 25. Where rigid metal conduit (RMC) is used to protect a grounding conductor, the conduit must ________. A. Be isolated from the grounding conductor B. Be electrically continuous from cabinet to ground clamps C. Be identified with green paint D. Not be connected to or touching the ground clamp

52. QuestionAnswerReferenceNEC PG. # 25.B250.64(E)114

53. Click here to advance to non- timed drill

54. O 1. Given: Two (2) rigid metal conduits (RMC) are to support a weatherproof 18 cu. In. device box, with threaded hubs, which contains a 125-volt, 20-ampere receptacle outlet. The conduits are to be threaded wrench tight into the hubs and, in general, shall be secured with at LEAST _____ of the enclosure. A. 8 inches B. 12 inches C. 18 inches D. 24 inches

55. QuestionAnswerReferenceNEC PG. # 1.C314.23(F)181

56. O 2. In general, if the cablebus system is rated 95 amperes, the MAXIMUM allowable rating of the overcurrent device used to protect the cablebus is _______. A. 80 amperes B. 90 amperes C. 95 amperes D. 100 amperes

57. QuestionAnswerReferenceNEC PG. # 2.D370.5227 240.4(B)(2)&(3)90 240.6(A)91

58. O 3. A twenty-five (25) ft. long tap conductor tapped from a 100 ampere rated feeder conductor, shall have an ampacity of NOT less than ________. A. 50 amperes B. 75 amperes C. 25 amperes D. 33.3 amperes

59. QuestionAnswerReferenceNEC PG. # 3.D240.21(B)&(B)(2)(1)92&93 100 amperes/3 = 33.3 amperes

60. O 4. Disregarding exceptions, bonding between Class I locations and the point of grounding for service equipment may be done by _________. A. Double locknuts B. Bonding jumpers C. Insulated bushings D. Metal raceways

61. QuestionAnswerReferenceNEC PG. # 4.B501.30(A)381

62. O 5. Determine the demand load, in VA, on the ungrounded service-entrance conductors, for the general-lighting and receptacles for a 25,000 sq. ft. office building that has one hundred-fifty (150) general-purpose duplex receptacles. Consider the service overcurrent protection device is NOT listed for continuous use. A. 112,075 VA B. 106,000 VA C. 90,200 VA D. 127,875 VA

63. QuestionAnswerReferenceNEC PG. # 5.DTbl. 220.1263 220.14(I)63 220.4464 Tbl. 220.4464 Art. 10027 230.42(A)(1)82 25,000 sq. ft. x 3.5 VA x 125% (lighting) = 109,375 VA 150 receptacles x 180 VA each = 27,000VA 1 st 10,000 VA @ 100% = 10,000 VA 27,000 VA – 10,000 VA = 17,000 VA @ 50% = 8,500VA Total = 127,875 VA

64. O 6. When an electrical service is required to have a grounded conductor present, what is the smallest grounded conductor permitted for an electric service using size 1000 kcmil copper undergrounded (phase) conductors? A. 3/0 AWG copper B. 2/0 AWG copper C. 1/0 AWG copper D. 4/0 AWG copper

65. QuestionAnswerReferenceNEC PG. # 6.B250.24(C)(1)105 Tbl. 250.66115

66. O 7. Determine the MINIMUM number of 20- ampere, 277-volt, general-lighting branch circuits required for a 150,000 sq. ft. department store, when the actual connected lighting load is 400 kVA, A. 72 branch circuits B. 82 branch circuits C. 91 branch circuits D. 102 branch circuits

67. QuestionAnswerReferenceNEC PG. # 7.C210.19(A)91)52 210.11(B)51 400 kVA = 400,000 VA x 125% (continuous load) = 500,000 VA (bldg.) 277 volts x 20 amperes = 5540 VA (one circuit) 500,000 VA. (bldg. lighting) 5,540 VA (one circuit) = 90.2 = 91 circuits *NOTE – Circuits need only to be installed to service the connected load.

68. O 8. Where a two-gang box contains two (2) single-pole switches, unless the box is equipped with permanently installed barriers, the voltage between the switches shall NOT be in excess of _______. A. 120 volts B. 277 volts C. 240 volts D. 300 volts

69. QuestionAnswerReferenceNEC PG. # 8.D404.8(B)268

70. O 9. An aluminum grounding electrode shall be _________. A. Installed at least 18 inches above the earth B. Installed at least 24 inches above the earth C. In direct earth burial D. Prohibited

71. QuestionAnswerReferenceNEC PG. # 9.D250.52(B)(2)112

72. O 10. A panelboard is limited to 42 overcurrent protective devices where ________. A. The panelboard is a power panelboard B. The panelboard is a “split-bus” type panelboard C. The panelboard supplies lighting branch-circuits only D. One is installed

73. QuestionAnswerReferenceNEC PG. # 10.B408.36, Ex. 2276

74. O 11. When rigid polyvinyl chloride conduit (PVC) is used to enclose conductors feeding a wet-niche luminaire in a permanently installed swimming pool, a ______ insulated copper grounding conductor shall be installed in this conduit, unless a listed low- voltage lighting system not requiring grounding is used. A. 12 AWG B. 10 AWG C. 8 AWG D. 6 AWG

75. QuestionAnswerReferenceNEC PG. # 11.C680.23(B)(2)(b)581

76. O 12. In general, what is the largest size transformer, in kVA, that may be installed in an area or room that is NOT constucted in a fire-resistant manner? A. 75 KVA B. 112 ½ KVA C. 150 KVA D. 50 KVA

77. QuestionAnswerReferenceNEC PG. # 12.B450.21(B)352

78. O 13. When calculating the total load of an office building, and the number of general- purpose receptacles to be installed is not yet determined, an additional load of _____ volt- amp(s) per square foot is required for the receptacle outlets. A. One B. Two C. One-Half D. Three

79. QuestionAnswerReferenceNEC PG. # 13.A220.14(K)(2)63

80. O 14. When sizing time-delay Class CC fuses for motor branch-circuit, short-circuit and ground-fault protection, they are to be sized at the same value as ________. A. inverse-time circuit breakers B. Nontime-delay fuses C. Instantaneous trip circuit breakers D. Adjustable trip circuit breakers

81. QuestionAnswerReferenceNEC PG. # 14.BTbl. 430.52, Note 1323

82. O 15. Conductors other than service-entrance conductors shall be permitted to be installed in a cable tray with service-entrance conductors provided __________. A. A solid fixed barrier of material compatible with the cable tray is installed to separate the systems B. The conductors are not in excess of 480 volts to ground C. The voltage between the conductors is not in excess of 600 volts D. The conductors have equal insulation and temperature ratings

83. QuestionAnswerReferenceNEC PG. # 15.A203.44, Ex82

84. O 16 The MAXIMUM allowable ampacity of a size 750 kcmil XHHW aluminum conductor where there are six (6) current-carrying conductors in the raceway, installed in a dry location, where the ambient temperature will reach 22°C is ________ A. 323.40 amperes B. 365.40 amperes C. 361.92 amperes D. 348.00 amperes

85. QuestionAnswerReferenceNEC PG. # 16.CTbl. 310.15(B)(16)154 Tbl. 310.15(B)(2)(a)150 Tbl. 310.15(B)(3)(a)152 Size 750 kcmil AL ampacity (before derating) = 435 amperes 435 amps x 1.04 (temp correction) x.8 (adj. factor) = 361.92 amperes

86. O 17. In which of the following locations is a cable tray prohibited to be installed? A. Basement B. Storage Rooms C. Sealed Ceiling Spaces D. When Passing Through a Wall

87. QuestionAnswerReferenceNEC PG. # 17.C392.18 (D)&(E)240

88. O 18. What is the MINIMUM size copper common grounding electrode conductor required to run through a building to four (4) separately derived systems (transformers) each having size 3/0 AWG copper secondary conductors. A. 4 AWG B. 2 AWG C. 3/0 AWG D. 8 AWG

89. QuestionAnswerReferenceNEC PG. # 18.C250.30(A)(6)(a)(1)108

90. O 19. Where a commercial building has a 600 ampere, 3-phase, 208Y/120 volt service supplied with two (2) paralled sets of size 350 kcmil copper conductors installed in separate raceways, determine the MINIMUM size aluminum grounding electrode conductor permitted to the metal water piping system used as the grounding electrod. A. 250 kcmil B. 4/0 AWG C. 3/0 AWG D. 2/0 AWG

91. QuestionAnswerReferenceNEC PG. # 19.B250.66115 Tbl. 250.66115 350 kcmil x 2 conductors = 750 kcmil *NOTE – A size 4/0 AWG aluminum grounding electrode conductor should be selected

92. O 20. The NEC permits trade size 3/8 in. flexible metal conduit (FMC) to be used to enclose tap conductors for luminaires, provided the length of the FMC does NOT exceed __________. A. 4 feet B. 6 feet C. 8 feet D. 10 feet

93. QuestionAnswerReferenceNEC PG. # 20.B348.20(A)(2)c.206

94. O 21. What is the MAXIMUM distance allowed to support intermediate metal conduit (IMC) from a junction box, where structural members do not readily permit fastening? A. 3 feet B. 5 feet C. 6 feet D. 8 feet

95. QuestionAnswerReferenceNEC PG. # 21.B342.30(A)(2)203

96. O 22. All of the following listed copper conductors are to be installed in an electrical metallic tubing (EMT) that is in excess of 24 inches long.  24-size 10 AWG with TW insulation  10-size 10 AWG with THW insulation  14-size 12 AWG with THHN insulation Determine the MINIMUM trade size of EMT required. A. 2 in. B. 2 ½ in. C. 3 in. D. 3 ½ in.

97. QuestionAnswerReferenceNEC PG. # 22.AChpt. 9, Tbl. 5717&718 Chpt. 9, Tbl. 4712 Size 10 AWG TW =.0243 sq. in. x 24 =.5832 sq. in. Size 10 AWG THW =.0243 sq. in. x 10 =.2430 sq. in. Size 12 AWG THNN =.0133 sq. in. x 14 =.1862 sq. in. TOTAL = 1.1024 sq. in. *NOTE – Trade size 2 inch EMT with a permitted fill of 1.342 sq. in. @ 40% should be selected

98. O 23. When combination surface nonmetallic raceways are used both for signaling and for power and lighting circuits, the different systems shall be ________. A. Prohibited B. Run in the same compartment C. Separated by at least ½ in. D. Run in separate compartments

99. QuestionAnswerReferenceNEC PG. # 23.D388.70238

100. O 24. When sizing fuses for a branch circuit serving a hermetic refrigerant motor- compressor, the device shall NOT exceed ____ of the rated load current marked on the nameplate of the equipment. A. 115 percent B. 125 percent C. 175 percent D. 225 percent

101. QuestionAnswerReferenceNEC PG. # 24.D440.22(A)343

102. O 25. Where rigid metal conduit (RMC) is used to protect a grounding conductor, the conduit must ________. A. Be isolated from the grounding conductor B. Be electrically continuous from cabinet to ground clamps C. Be identified with green paint D. Not be connected to or touching the ground clamp

103. QuestionAnswerReferenceNEC PG. # 25.B250.64(E)114