1. Conductors and Cables 2017 NEC
© Ted “Smitty” Smith
E Light Electric Services, Inc.

2. Click the slides to advance to the next slide as you are ready.
You will reach a slide which says “START”. This is the beginning of the timed portion of the drill. Click that slide and the question slides will start running. Each slide will remain in place for 2 minutes. A sound will go off letting you know that it has moved to the next slide. Attempt to answer the question. If you finish before the timer goes off, click the slide and it will go to the next question. If you do not finish, simply stop working that problem and start on the next. When you reach the end of the timed portion you will see a slide that says “STOP”. Click on that slide and each of the questions will reappear and this time you can click them to move to the next slide, which will have the answer.
Please call me if you have any issues or questions and I will be happy to arrange a time for us to review.
Directions

3. Where are these rules found?
Most of the rules for conductors and cables are found in Chapter 3
Article 300 contains the general installation rules such as underground, installed in wood studs, installed under metal roofs, wet location installations and the like
Article 310 contains ampacity and parallel installation rules
Article 312 contains wire bending space rules
Article 314 contains box fill rules
Articles contain specific rules for specific cables
Key Tables
(B2A) (B3A) and )(B16 ) Ampacity Determination
(A) Conductor Applications
Chapter 9 Tables 4 and 5 Raceway Fill Calculations
Chapter 9 Table 8 Conductor Properties
312.6 Wire Bending Space

4. Key Points to Remember Rules for parallel installation of conductors
All conductors under 1000V are considered low voltage. Therefore 24V, 120V and 480V conductors CAN all be in the same raceway, box, etc.
300.3(C)(1)
NOTE: It is not good practice but it is allowed.
Rules for parallel installation of conductors
1. Must be at least 1/0 AWG
2. Must be the same length
3. Must be the same material
4. Must be the same insulation
5. Must be terminated the same way
310.10(H)
Rules for underground wiring
How deep they have to be installed in 300.5
If exposed to different temperatures, for example going from the inside of a building to the outside the raceway must be 300.7
All underground or below ground installations are considered wet locations

5. Armored Cable (AC) and Metal Clad Cable (MC) are not the same thing.
Armored Cable, Article 320
Must be supported every 4 ½ feet
Not permitted in damp or wet locations
Not permitted where subject to physical damage
Not permitted to be embedded in plaster or masonry
Metal Clad Cable, Article 330
Must be supported every 6 feet
Permitted in damp and wet locations
May be installed indoors and outdoors
May be embedded in plater and masonry

6. Click here to start the timed portion of the Drill

7. What is the ampacity of a three wire, 6 AWG SO cord?

8. B. 45 A
T 400.5(A)(1) Column A

9. 2. What is the ampacity of 18 AWG PFF wire? A. 6 B. 8 C. 17 D. 23

10. A. 6
T 402.5
PFF is a type of fixture wire. It is listed in T 402.3

11. 3. What is the minimum sized flexible metal conduit required if the conduit will be 6 feet in length and it will contain the following conductors: (11) THHN 12 AWG conductors and (3) THHN 10 AWG conductors?
A. ½”
B. ¾”
C. 1”
D. 1 ¼”

12. B. ¾”
Tables 4 and 5 Chapter 9

13. Copyright 2005 Ted "Smitty" Smith
4. Which of the following is NOT a condition in which MC cable is permitted to be installed unsupported and unsecured?
A. When fished between access points though concealed spaces in finished buildings
B. Is type MC of interlocked armor type in lengths not exceeding 1100 mm from the last point where it is securely fastened when used to connect equipment where flexibility is needed to minimize the effects of vibration
C. Is not more than 1.8 m in length from the last cable support to the point of connection to luminaires or other electrical equipment
D. Is type MC of interlocked armor type in lengths not exceeding 900 mm from the last point where it is securely fastened when used to connect equipment where flexibility is needed to minimize the effects of vibration
Copyright 2005 Ted "Smitty" Smith

14. B.
330.30(D)

15. Copyright 2005 Ted "Smitty" Smith
5. Where NM cable is installed in wood framing members the holes through which the cable will travel shall be drilled so that the edge of the hole is at least ________ inches from the nearest edge of the wood member. A. ¾” B. 1” C. 1 ¼” D. 2”
Copyright 2005 Ted "Smitty" Smith

16. C. 1 ¼”
300.4(A)

17. 6. Two separate NM cables will be installed through wood framing members in a dwelling unit. The cables will each be a 14/2 NM cable. There will be only one hole drilled in each stud, which both cables will pass through. The cables will each feed a 15 ampere rated load. Is this an acceptable installation? A. Yes B. No

18. Yes
334.80
T310.15(B16)
The 90C column can be used for derating which is 25 A
We do have to derate because we are not maintaining spacing. 80% which is 20 A.
Then we have to make sure that the load does not exceed the ampacity in the 60C column which is 15 A. So we are good.

19. 7. Mounting screws which pass through the interior of an outlet box shall pass through the interior within ______ inches of the back or ends of the enclosure. A. 1” B. ½” C. ¼” D. 1/8”

20. C. ¼” (B)(1)

21. Copyright 2008 Ted "Smitty" Smith
8. What is the minimum wire bending space required for three parallel runs of 250 kCMIL conductors which will be terminated on non-lay in lugs in a panel. The conductors will enter the panel on the wall that is not opposite to the lugs. A. 6 B. 8 C. 10 D. 12
Copyright 2008 Ted "Smitty" Smith

22. B. 8 inches 312.6(B)(1)

23. Copyright 2008 Ted "Smitty" Smith
9. Type TC (Power and Control Tray Cable) is permitted to be used in single family dwellings for both power and control conductors if it is ________________________. A. labeled for pulling through structural members B. identified for pulling through structural members C. part of a bundled wiring assembly listed for pulling through structural members D. approved in writing by the AHJ.
Copyright 2008 Ted "Smitty" Smith

24. B. Identified for pulling through structural members 336.10(9)

25. Copyright 2008 Ted "Smitty" Smith
Three conductor SE cable with size 10 AWG ungrounded conductors is installed as branch circuit conductors. Which conductor temperature rating shall be used to determine the conductor’s ampacity?
50 degrees C
60 degrees C
75 degrees C
90 degrees C
Copyright 2008 Ted "Smitty" Smith

26. B. 60 degrees C (B)(4)

27. CLICK HERE TO PROCEED WITHOUT THE TIMER AND REVIEW THE QUESTIONS AND ANSWERS

28. What is the ampacity of a three wire, 6 AWG SO cord?

29. B. 45 A
T 400.5(A)(1) Column A

30. 2. What is the ampacity of 18 AWG PFF wire? A. 6 B. 8 C. 17 D. 23

31. A. 6
T 402.5
PFF is a type of fixture wire. It is listed in T 402.3

32. 3. What is the minimum sized flexible metal conduit required if the conduit will be 6 feet in length and it will contain the following conductors: (11) THHN 12 AWG conductors and (3) THHN 10 AWG conductors?
A. ½”
B. ¾”
C. 1”
D. 1 ¼”

33. B. ¾”
Tables 4 and 5 Chapter 9

34. Copyright 2005 Ted "Smitty" Smith
4. Which of the following is NOT a condition in which MC cable is permitted to be installed unsupported and unsecured?
A. When fished between access points though concealed spaces in finished buildings
B. Is type MC of interlocked armor type in lengths not exceeding 1100 mm from the last point where it is securely fastened when used to connect equipment where flexibility is needed to minimize the effects of vibration
C. Is not more than 1.8 m in length from the last cable support to the point of connection to luminaires or other electrical equipment
D. Is type MC of interlocked armor type in lengths not exceeding 900 mm from the last point where it is securely fastened when used to connect equipment where flexibility is needed to minimize the effects of vibration
Copyright 2005 Ted "Smitty" Smith

35. B.
330.30(D)

36. Copyright 2005 Ted "Smitty" Smith
5. Where NM cable is installed in wood framing members the holes through which the cable will travel shall be drilled so that the edge of the hole is at least ________ inches from the nearest edge of the wood member. A. ¾” B. 1” C. 1 ¼” D. 2”
Copyright 2005 Ted "Smitty" Smith

37. C. 1 ¼”
300.4(A)

38. 6. Two separate NM cables will be installed through wood framing members in a dwelling unit. The cables will each be a 14/2 NM cable. There will be only one hole drilled in each stud, which both cables will pass through. The cables will each feed a 15 ampere rated load. Is this an acceptable installation? A. Yes B. No

39. Yes
334.80
T310.15(B16)
The 90C column can be used for derating which is 25 A
We do have to derate because we are not maintaining spacing. 80% which is 20 A.
Then we have to make sure that the load does not exceed the ampacity in the 60C column which is 15 A. So we are good.

40. 7. Mounting screws which pass through the interior of an outlet box shall pass through the interior within ______ inches of the back or ends of the enclosure. A. 1” B. ½” C. ¼” D. 1/8”

41. C. ¼” (B)(1)

42. Copyright 2008 Ted "Smitty" Smith
8. What is the minimum wire bending space required for three parallel runs of 250 kCMIL conductors which will be terminated on non-lay in lugs in a panel. The conductors will enter the panel on the wall that is not opposite to the lugs. A. 6 B. 8 C. 10 D. 12
Copyright 2008 Ted "Smitty" Smith

43. B. 8 inches 312.6(B)(1)

44. Copyright 2008 Ted "Smitty" Smith
9. Type TC (Power and Control Tray Cable) is permitted to be used in single family dwellings for both power and control conductors if it is ________________________. A. labeled for pulling through structural members B. identified for pulling through structural members C. part of a bundled wiring assembly listed for pulling through structural members D. approved in writing by the AHJ.
Copyright 2008 Ted "Smitty" Smith

45. B. Identified for pulling through structural members 336.10(9)

46. Copyright 2008 Ted "Smitty" Smith
Three conductor SE cable with size 10 AWG ungrounded conductors is installed as branch circuit conductors. Which conductor temperature rating shall be used to determine the conductor’s ampacity?
50 degrees C
60 degrees C
75 degrees C
90 degrees C
Copyright 2008 Ted "Smitty" Smith

47. B. 60 degrees C (B)(4)