EETC Conduit & Raceway Systems 1 — Questions and Answers
Question 1: According to NEC Chapter 9, Table 1, what is the maximum percentage of conduit cross-sectional area that conductors may occupy when three or more conductors are installed?
- 31%
- 40% (Correct answer)
- 53%
- 60%
Correct answer: 40%
NEC Chapter 9, Table 1 limits conduit fill to 40% of the cross-sectional area when three or more conductors are installed to allow for heat dissipation and future wire pulling.
Question 2: Which conduit type has the thinnest wall and is NOT suitable for direct burial in soil without additional protection?
- Rigid Metal Conduit (RMC)
- Intermediate Metal Conduit (IMC)
- Electrical Metallic Tubing (EMT) (Correct answer)
- Rigid PVC Schedule 80
Correct answer: Electrical Metallic Tubing (EMT)
EMT has the thinnest wall of the metallic conduit types and is not listed for direct burial in soil; it is intended for surface or concealed installations in protected locations.
Question 3: What is the maximum total degrees of bends permitted in a single conduit run between pull points according to the NEC?
- 180°
- 270°
- 360° (Correct answer)
- 450°
Correct answer: 360°
The NEC limits the total bends between pull points to 360° (equivalent to four 90° bends) to ensure conductors can be pulled without excessive damage.
Question 4: Liquidtight Flexible Metal Conduit (LFMC) is most commonly specified for:
- Long straight runs in industrial facilities
- Underground service entrance conductors
- Final connections to motors and other vibrating equipment (Correct answer)
- Surface wiring in finished commercial spaces
Correct answer: Final connections to motors and other vibrating equipment
LFMC is designed to provide a flexible, liquidtight connection ideal for motor terminations and equipment subject to vibration, movement, or exposure to liquids.
Question 5: Which type of conduit is specifically listed and approved for direct burial in soil and concrete encasement?
- Electrical Metallic Tubing (EMT)
- Flexible Metal Conduit (FMC)
- Rigid PVC Conduit (Schedule 40) (Correct answer)
- Surface Metal Raceway
Correct answer: Rigid PVC Conduit (Schedule 40)
Rigid PVC conduit (Schedule 40 and Schedule 80) is listed for direct burial in soil and concrete encasement, making it a common choice for underground runs.
Question 6: Per NEC Chapter 9, Table 1, when a conduit contains only one conductor, the maximum permitted fill is:
- 31%
- 40%
- 53% (Correct answer)
- 60%
Correct answer: 53%
The NEC allows a single conductor to occupy up to 53% of the conduit's cross-sectional area because heat dissipation is less of a concern with only one conductor.
Question 7: Surface Metal Raceway (such as Wiremold) differs from standard conduit primarily because it:
- Must be installed underground
- Has a removable cover allowing easy access to installed conductors (Correct answer)
- Can only carry low-voltage wiring
- Requires a separate grounding conductor at all times
Correct answer: Has a removable cover allowing easy access to installed conductors
Surface metal raceway features a snap-on or screwed cover that can be removed at any point, making it ideal for retrofit installations where access to conductors is needed without conduit pulls.
EETC Conduit & Raceway Systems 1
According to NEC Chapter 9, Table 1, what is the maximum percentage of conduit cross-sectional area that conductors may occupy when three or more conductors are installed?