Licensed Electrical Contractor Wiring Methods and Materials 3

Question 1

When using liquidtight flexible nonmetallic conduit (LFNC), what is the maximum length permitted for a single run used as a fixed raceway?

Accepted Answer

6 feet

Answer

NEC 356.60 limits LFNC used as a fixed raceway to 6 feet in length except where used for lighting fixtures or where flexibility is necessary.

Question 2

Which insulation type is rated for use in both wet and dry locations at 75°C?

Accepted Answer

THW

Answer

Type THW is rated 75°C in both wet and dry locations, making it suitable for outdoor or damp environment wiring.

Question 3

Intermediate metal conduit (IMC) has a wall thickness that is:

Accepted Answer

Thinner than RMC but thicker than EMT

Answer

IMC has a wall thickness between the heavy-wall RMC and the thin-wall EMT, offering a balance of strength and weight savings.

Question 4

What is the maximum ambient temperature rating for Type THHN conductors?

Accepted Answer

90°C

Answer

Type THHN conductors are rated for 90°C in dry locations, though ampacity is typically derated to 75°C at terminations per NEC 110.14(C).

Question 5

When Type NM cable passes through a metal framing member, which protection is required?

Accepted Answer

A steel nail plate at least 1/16 inch thick

Answer

NEC 300.4(B)(1) requires a steel nail plate at least 1/16-inch thick to protect NM cable passing through metal framing members less than 1-1/4 inches from the edge.

Licensed Electrical Contractor Practice Test

Licensed Electrical Contractor Practice Test

Licensed Electrical Contractor Wiring Methods and Materials 3