Journeyman Electrician’s Exam Journeyman Electrician's Raceway Systems 2 — Questions and Answers
Question 1: According to NEC Chapter 9, Table 1, what is the maximum conduit fill percentage when only ONE conductor is installed in a raceway?
- 31%
- 40%
- 53% (Correct answer)
- 60%
Correct answer: 53%
NEC Chapter 9, Table 1 permits a single conductor to fill up to 53% of the conduit's total cross-sectional area, allowing room for pulling and heat dissipation.
Question 2: What is the maximum conduit fill percentage when exactly TWO conductors are installed in a raceway, per NEC Chapter 9, Table 1?
- 31% (Correct answer)
- 40%
- 53%
- 60%
Correct answer: 31%
Two conductors in a conduit are limited to 31% fill per NEC Chapter 9, Table 1, because two round conductors side-by-side leave large voids and resist pulling.
Question 3: When three or more conductors are installed in a conduit, what is the maximum fill percentage per NEC Chapter 9, Table 1?
- 31%
- 40% (Correct answer)
- 53%
- 60%
Correct answer: 40%
Three or more conductors in a conduit are limited to 40% fill per NEC Chapter 9, Table 1, providing adequate space for pulling and preventing overheating.
Question 4: Conduit nipples that do not exceed 24 inches in length may be filled to what maximum percentage per NEC Chapter 9, Table 1 Note 4?
- 40%
- 53%
- 60% (Correct answer)
- 75%
Correct answer: 60%
Short conduit nipples (24 inches or less) may be filled to 60% of cross-sectional area because conductors only need to be pushed through a very short distance rather than pulled through a long run.
Question 5: Where are the cross-sectional areas of insulated conductors for conduit fill calculations found in the NEC?
- Chapter 9, Table 1
- Chapter 9, Table 4
- Chapter 9, Table 5 (Correct answer)
- Annex C
Correct answer: Chapter 9, Table 5
NEC Chapter 9, Table 5 lists the dimensions and cross-sectional areas of insulated conductors and fixture wires used to calculate conduit fill.
Question 6: Where in the NEC are the cross-sectional areas and dimensions of conduit and tubing found for fill calculations?
- Chapter 9, Table 1
- Chapter 9, Table 4 (Correct answer)
- Chapter 9, Table 5
- Annex B
Correct answer: Chapter 9, Table 4
NEC Chapter 9, Table 4 provides the dimensions and usable cross-sectional areas (total, 40%, 53%, and 60%) for all types of conduit and tubing.
Question 7: When performing a conduit fill calculation for conductors of different insulation types, what determines each conductor's contribution to the total fill area?
- The conductor AWG size only
- The outer diameter including insulation (Correct answer)
- The bare conductor cross-section only
- The voltage rating of the insulation
Correct answer: The outer diameter including insulation
Conduit fill is based on the total cross-sectional area of each conductor including its insulation as listed in NEC Chapter 9, Table 5, organized by insulation type and wire size.
