1. Calculation Speed Drill # 3 2008 NEC
©Ted “Smitty” Smith 2008, 2011
THIS DRILL MAY ALSO BE USED IN ACCORDANCE WITH THE 2011 NEC.

2. Instructions
This speed drill focuses on calculations that will be required for the journeyman and masters examination.
The question slide will still transition in 3 ½ minutes for calculations and 2 mins for code look up questions and will be followed by the correct answer which will stay on the screen for only 10 seconds.
Do not worry about writing down the correct answer during the transition. At the end of the questions, a stop slide will appear and then that will be followed by the questions and answers without the timer so you can review them.
You must click on the screen icon in the lower right hand or left corner of the tool bar to start the slide show in order for the timer to operate.

3. How many watts is used by a 10 hp motor?

4. 7460 Watts
746 x 10= 7460

5. What is the ampacity of NM cables installed in a bored hole if the cables are 10-2 with ground and there are a total of three cables installed in the bored hole?

6. 30 amperes
Must derate based on 90 C column and conductors in a raceway or cable table. There are six current carrying conductors. 10 AWG is 40 amperes and six conductors requires .80 derating. 40X.80= 32
also states that the adjusted ampacity can not exceed the value found in the 60 C column of
60 C column is 30 amperes for #10 AWG copper.

7. What is the minimum sized equipment grounding conductor required for a circuit that is supplied by a 400A inverse time, overcurrent protective device?

8. Table
#3 Copper or #1 Aluminum

9. A disconnecting means for an emergency system or fire pump shall be installed __________________ from the one to six service disconnecting means for normal service.
Copyright 2005 Ted "Smitty" Smith

10. Remote, away from
230.72

11. IMC conduit shall be installed so that it is supported in intervals not exceeding ___________ feet?
Copyright 2005 Ted "Smitty" Smith

12. 10 feet
342.30(B)

13. Motor Calculation
What is the maximum branch circuit- short circuit protection allowed for a 208V, three phase, squirrel cage motor with the following nameplate ratings:
20 hp, 51.6 A FLC, 1.15 Service Factor, and Design B
The short circuit protection will be done with an inverse time circuit breaker.

14. Motor Calculation
150 ampere inverse time breaker.

15. Raceway Fill
What is the minimum trade name size conduit that can be used for a 310 foot conduit run that will contain nine 10 AWG TW conductors, five 2 AWG RHW conductors with outer covering, and two 6 AWG RHH conductors that do not have an outer covering? The wires will be installed in an intermediate metal conduit.

16. Raceway Fill
The total area of the conductors is and a 2” IMC at 31% fill will allow 2”

17. 1. Standard trade size 2-inch rigid polyvinyl chloride conduit (PVC), shall be supported at least every _____.
3 feet
5 feet
6 feet
8 feet
Ted "Smitty" Smith
4/22/2017

18. 1. b Tbl
Ted "Smitty" Smith
4/22/2017

19. inverse-time circuit breakers Non-time-delay fuses
2. 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 _____.
inverse-time circuit breakers
Non-time-delay fuses
Instantaneous trip circuit breakers
Adjustable trip circuit breakers
Ted "Smitty" Smith
4/22/2017

20. 2. b Tbl ,Note 1
Ted "Smitty" Smith
4/22/2017

21. 3. Where sizes 1/0 AWG single conductor cables are installed in ladder type cable tray, the MAXIMUM allowable rung spacing for the ladder cable tray shall be _____.
6 inches
9 inches
12 inches
15 inches
Ted "Smitty" Smith
4/22/2017

22. 3. b 392.3(B)(1)(a)
Ted "Smitty" Smith
4/22/2017

23. 4. The NEC® requires the MAXIMUM length permitted for a flexible cord supplying a 208-volt, single-phase, room air-conditioner to be ____.
4 feet
6 feet
8 feet
10 feet
Ted "Smitty" Smith
4/22/2017

24. 4. b
Ted "Smitty" Smith
4/22/2017

25. All 125-volt, single phase, 15- and 20-ampere rated receptacles.
5. In general, which of the following receptacle outlets in a commercial kitchen are required by the NEC® to be GFCI protected?
All 125-volt, single phase, 15- and 20-ampere rated receptacles.
All 125-volt, 15- or 20-ampere rated receptacles in wet locations only.
All receptacle outlets.
All 125-volt countertop receptacle outlets only.
Ted "Smitty" Smith
4/22/2017

26. 5. a 210.8(B)(2)
Ted "Smitty" Smith
4/22/2017

27. 6. All wiring installed in or under an aircraft hanger floor shall comply with the requirements for ______ locations.
Class I, Division 1
Class I, Division 2
Class II, Division 1
Class II, Division 2
Ted "Smitty" Smith
4/22/2017

28. 6. a 513.8(A)
Ted "Smitty" Smith
4/22/2017

29. 7. In general, branch-circuit conductors supplying more than one motor shall have an ampacity of a at least _____ percent of the FLC of the largest motor, and 100 percent of the FLC of the other motor(s) in the group. 25 80
100
125
Ted "Smitty" Smith
4/22/2017

30. 7. d
Ted "Smitty" Smith
4/22/2017

31. 8. What is the MINIMUM size equipment grounding conductor required for a 5 HP, three-phase, 208-volt motor having 20-ampere rated overload protection and short-circuit overcurrent protection rated at 30 amperes?
10 AWG
14 AWG
12 AWG
8 AWG
Ted "Smitty" Smith
4/22/2017

32. 8. a Tbl
Ted "Smitty" Smith
4/22/2017

33. The motor to be less than 2 HP.
9. If a circuit breaker serves as the controller for a motor, and the motor is not in sight of the breaker, the NEC® requires which of the following?
The motor to be less than 2 HP.
The breaker be able to be locked in the open position.
The motor to be Code letter “E”.
The breaker to be rated 25,000 AIC.
Ted "Smitty" Smith
4/22/2017

34. 9. b (B)(2), Ex.
Ted "Smitty" Smith
4/22/2017

35. 10. In Class II, Division 1, hazardous locations, an approved method of connection of conduit to boxes is _____.
Compression fittings
Threaded bosses
Welding
All of these
Ted "Smitty" Smith
4/22/2017

36. 10. b (A)(4)
Ted "Smitty" Smith
4/22/2017

37. 11. Given: an AC service is supplied with four parallel kcmil aluminum conductors. What is the MINIMUM size copper grounding electrode required, when connected to the concrete-encased building steel used as the grounding electrode system?
3/0 AWG
4/0 AWG
250 kcmil
2/0 AWG
Ted "Smitty" Smith
4/22/2017

38. 500 kcmil X 4 conductors = 2000 kcmil total
11. a Tbl
500 kcmil X 4 conductors = 2000 kcmil total
*NOTE: Aluminum service-entrance conductors over kcmil require a size 3/0 AWG copper grounding electrode conductor.
Ted "Smitty" Smith
4/22/2017

39. 12. Given: an AC transformer arc welder has a 50- ampere rated primary current and a 60 percent duty-cycle. Determine the MINIMUM size copper 60°C rated conductors the NEC® requires to supply this welder.
6 AWG
8 AWG
10 AWG
4 AWG
Ted "Smitty" Smith
4/22/2017

40. .78 (duty cycle) X 50 amperes (primary current) = 39 amperes
12. b Tbl (A)
Tbl
.78 (duty cycle) X 50 amperes (primary current) = 39 amperes
Tbl requires a size 8 AWG conductor.
Ted "Smitty" Smith
4/22/2017

41. 13. When installing wiring for sensitive electronic equipment, the MAXIMUM voltage to ground is required to be ____ volts. 30 60
120
300
Ted "Smitty" Smith
4/22/2017

42. 13. b 647.1
Ted "Smitty" Smith
4/22/2017

43. Stop This is the end of the presentation.
You can now review the slides and answers without the timer.
Click the slide to advance to the next slide

44. Calculation Speed Drill # 3 2008 NEC
©Ted “Smitty” Smith 2008

45. Instructions
This speed drill focuses on calculations that will be required for the journeyman and masters examination.
The question slide will still transition in 3 ½ minutes and will be followed by the correct answer which will stay on the screen for only 10 seconds.
Do not worry about writing down the correct answer during the transition. At the end of the questions, a stop slide will appear and then that will be followed by the questions and answers without the timer so you can review them.
You must click on the screen icon in the lower right hand or left corner of the tool bar to start the slide show in order for the timer to operate.

46. How many watts is used by a 10 hp motor?

47. 7460 Watts
746 x 10= 7460

48. What is the ampacity of NM cables installed in a bored hole if the cables are 10-2 with ground and there are a total of three cables installed in the bored hole?

49. 30 amperes
Must derate based on 90 C column and conductors in a raceway or cable table. There are six current carrying conductors. 10 AWG is 40 amperes and six conductors requires .80 derating. 40X.80= 32
also states that the adjusted ampacity can not exceed the value found in the 60 C column of
60 C column is 30 amperes for #10 AWG copper.

50. What is the minimum sized equipment grounding conductor required for a circuit that is supplied by a 400A inverse time, overcurrent protective device?

51. Table
#3 Copper or #1 Aluminum

52. A disconnecting means for an emergency system or fire pump shall be installed __________________ from the one to six service disconnecting means for normal service.
Copyright 2005 Ted "Smitty" Smith

53. Remote, away from
230.72

54. IMC conduit shall be installed so that it is supported in intervals not exceeding ___________ feet?
Copyright 2005 Ted "Smitty" Smith

55. 10 feet
342.30(B)

56. Motor Calculation
What is the maximum branch circuit- short circuit protection allowed for a 208V, three phase, squirrel cage motor with the following nameplate ratings:
20 hp, 51.6 A FLC, 1.15 Service Factor, and Design B
The short circuit protection will be done with an inverse time circuit breaker.

57. Motor Calculation
150 ampere inverse time breaker.

58. Raceway Fill
What is the minimum trade name size conduit that can be used for a 310 foot conduit run that will contain nine 10 AWG TW conductors, five 2 AWG RHW conductors with outer covering, and two 6 AWG RHH conductors that do not have an outer covering? The wires will be installed in an intermediate metal conduit.

59. Raceway Fill
The total area of the conductors is and a 2” IMC at 31% fill will allow 2”

60. 1. Standard trade size 2-inch rigid polyvinyl chloride conduit (PVC), shall be supported at least every _____.
3 feet
5 feet
6 feet
8 feet
Ted "Smitty" Smith
4/22/2017

61. 1. b Tbl
Ted "Smitty" Smith
4/22/2017

62. inverse-time circuit breakers Non-time-delay fuses
2. 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 _____.
inverse-time circuit breakers
Non-time-delay fuses
Instantaneous trip circuit breakers
Adjustable trip circuit breakers
Ted "Smitty" Smith
4/22/2017

63. 2. b Tbl ,Note 1
Ted "Smitty" Smith
4/22/2017

64. 3. Where sizes 1/0 AWG single conductor cables are installed in ladder type cable tray, the MAXIMUM allowable rung spacing for the ladder cable tray shall be _____.
6 inches
9 inches
12 inches
15 inches
Ted "Smitty" Smith
4/22/2017

65. 3. b 392.3(B)(1)(a)
Ted "Smitty" Smith
4/22/2017

66. 4. The NEC® requires the MAXIMUM length permitted for a flexible cord supplying a 208-volt, single-phase, room air-conditioner to be ____.
4 feet
6 feet
8 feet
10 feet
Ted "Smitty" Smith
4/22/2017

67. 4. b
Ted "Smitty" Smith
4/22/2017

68. All 125-volt, single phase, 15- and 20-ampere rated receptacles.
5. In general, which of the following receptacle outlets in a commercial kitchen are required by the NEC® to be GFCI protected?
All 125-volt, single phase, 15- and 20-ampere rated receptacles.
All 125-volt, 15- or 20-ampere rated receptacles in wet locations only.
All receptacle outlets.
All 125-volt countertop receptacle outlets only.
Ted "Smitty" Smith
4/22/2017

69. 5. a 210.8(B)(2)
Ted "Smitty" Smith
4/22/2017

70. 6. All wiring installed in or under an aircraft hanger floor shall comply with the requirements for ______ locations.
Class I, Division 1
Class I, Division 2
Class II, Division 1
Class II, Division 2
Ted "Smitty" Smith
4/22/2017

71. 6. a 513.8(A)
Ted "Smitty" Smith
4/22/2017

72. 7. In general, branch-circuit conductors supplying more than one motor shall have an ampacity of a at least _____ percent of the FLC of the largest motor, and 100 percent of the FLC of the other motor(s) in the group. 25 80
100
125
Ted "Smitty" Smith
4/22/2017

73. 7. d
Ted "Smitty" Smith
4/22/2017

74. 8. What is the MINIMUM size equipment grounding conductor required for a 5 HP, three-phase, 208-volt motor having 20-ampere rated overload protection and short-circuit overcurrent protection rated at 30 amperes?
10 AWG
14 AWG
12 AWG
8 AWG
Ted "Smitty" Smith
4/22/2017

75. 8. a Tbl
Ted "Smitty" Smith
4/22/2017

76. The motor to be less than 2 HP.
9. If a circuit breaker serves as the controller for a motor, and the motor is not in sight of the breaker, the NEC® requires which of the following?
The motor to be less than 2 HP.
The breaker be able to be locked in the open position.
The motor to be Code letter “E”.
The breaker to be rated 25,000 AIC.
Ted "Smitty" Smith
4/22/2017

77. 9. b (B)(2), Ex.
Ted "Smitty" Smith
4/22/2017

78. 10. In Class II, Division 1, hazardous locations, an approved method of connection of conduit to boxes is _____.
Compression fittings
Threaded bosses
Welding
All of these
Ted "Smitty" Smith
4/22/2017

79. 10. b (A)(4)
Ted "Smitty" Smith
4/22/2017

80. 11. Given: an AC service is supplied with four parallel kcmil aluminum conductors. What is the MINIMUM size copper grounding electrode required, when connected to the concrete-encased building steel used as the grounding electrode system?
3/0 AWG
4/0 AWG
250 kcmil
2/0 AWG
Ted "Smitty" Smith
4/22/2017

81. 500 kcmil X 4 conductors = 2000 kcmil total
11. a Tbl
500 kcmil X 4 conductors = 2000 kcmil total
*NOTE: Aluminum service-entrance conductors over kcmil require a size 3/0 AWG copper grounding electrode conductor.
Ted "Smitty" Smith
4/22/2017

82. 12. Given: an AC transformer arc welder has a 50- ampere rated primary current and a 60 percent duty-cycle. Determine the MINIMUM size copper 60°C rated conductors the NEC® requires to supply this welder.
6 AWG
8 AWG
10 AWG
4 AWG
Ted "Smitty" Smith
4/22/2017

83. .78 (duty cycle) X 50 amperes (primary current) = 39 amperes
12. b Tbl (A)
Tbl
.78 (duty cycle) X 50 amperes (primary current) = 39 amperes
Tbl requires a size 8 AWG conductor.
Ted "Smitty" Smith
4/22/2017

84. 13. When installing wiring for sensitive electronic equipment, the MAXIMUM voltage to ground is required to be ____ volts. 30 60
120
300
Ted "Smitty" Smith
4/22/2017

85. 13. b 647.1
Ted "Smitty" Smith
4/22/2017

86. Stop This is the end of the presentation.
You can now review the slides and answers without the timer.
Click the slide to advance to the next slide