CEA Wiring Methods & Installation Practices 4 — Questions and Answers
Question 1: When installing conduit through fire-rated walls or floors, what is required?
- No special treatment is needed for metal conduit
- Fire-stop material approved for the application must seal the penetration (Correct answer)
- Conduit must be wrapped with fire tape for 6 inches on each side
- Conduit must be removed and rerouted around fire barriers
Correct answer: Fire-stop material approved for the application must seal the penetration
All conduit penetrations through fire-rated assemblies must be sealed with approved fire-stop materials to maintain the fire rating of the assembly.
Question 2: What is the maximum allowable voltage for conductors installed in the same raceway using NM cable?
- 120V
- 240V
- 300V
- 600V (Correct answer)
Correct answer: 600V
Type NM cable conductors are rated at 600V, which is the standard voltage rating for most branch circuit wiring methods in residential construction.
Question 3: When must a conduit body (LB, LL, LR) be sized to accommodate the conductors inside it?
- Always, regardless of conductor size
- Only when used as a pull point with conductors larger than 6 AWG (Correct answer)
- Only when more than three conductors are present
- Conduit bodies have no fill restrictions
Correct answer: Only when used as a pull point with conductors larger than 6 AWG
Conduit bodies used with conductors larger than 6 AWG must have a cross-sectional area of at least twice the cross-section of the largest conduit connected to it.
Question 4: Flexible metal conduit (FMC) is permitted to serve as the equipment grounding conductor if it meets which condition?
- FMC can never serve as an EGC
- FMC up to 6 feet long in circuits not exceeding 20A at 250V or less (Correct answer)
- FMC of any length for circuits up to 30A
- FMC can always serve as an EGC with a bonding jumper
Correct answer: FMC up to 6 feet long in circuits not exceeding 20A at 250V or less
FMC can serve as the EGC when the total length does not exceed 6 feet, the circuit does not exceed 20 amperes, and the circuit voltage is 250V or less.
Question 5: What is the minimum insulation rating required for conductors installed in a raceway exposed to direct sunlight on a rooftop?
- 60°C (140°F)
- 75°C (167°F)
- 90°C (194°F) (Correct answer)
- 110°C (230°F)
Correct answer: 90°C (194°F)
Conductors in raceways exposed to direct sunlight on rooftops must have a 90°C insulation rating and may require ampacity correction for elevated ambient temperatures.
Question 6: When NM cable runs parallel to framing members, what is the minimum clearance required from the edge of the framing?
- 1 inch
- 1.25 inches (Correct answer)
- 1.5 inches
- 2 inches
Correct answer: 1.25 inches
NM cable must be kept at least 1.25 inches from the edge of framing members to protect it from nails or screws.
Question 7: Liquidtight flexible nonmetallic conduit (LFNC) is permitted for use in which application?
- As a substitute for RMC in all outdoor locations
- In lengths up to 6 feet for direct burial without raceway
- For connections to motors and equipment requiring flexibility in wet or oily locations (Correct answer)
- In lengths exceeding 6 feet for all exterior applications
Correct answer: For connections to motors and equipment requiring flexibility in wet or oily locations
LFNC is approved for use in wet and oily locations where flexibility is needed, such as motor connections, in lengths not exceeding 6 feet.
CEA Wiring Methods & Installation Practices 4
When installing conduit through fire-rated walls or floors, what is required?