PC Wiring Methods and Protection 2

Question 1

What is the minimum cover requirement for direct-buried conductors rated 0–600V in a residential driveway under a concrete slab?

Accepted Answer

6 inches

Answer

12 inches

Answer

18 inches

Answer

24 inches

Question 2

Which wiring method is specifically listed for use in ducts, plenums, or other air-handling spaces without restriction?

Accepted Answer

EMT with THHN conductors

Answer

Type MC cable

Answer

Type AC cable

Answer

Electrical nonmetallic tubing (ENT)

Question 3

Per NEC 300.14, at least how much free conductor length must be left at each outlet, junction, or switch point?

Accepted Answer

6 inches

Answer

4 inches

Answer

8 inches

Answer

12 inches

Question 4

Flexible metal conduit (FMC) used as a grounding path must not exceed what maximum length?

Accepted Answer

6 feet

Answer

3 feet

Answer

8 feet

Answer

10 feet

Question 5

What is the maximum size of rigid metallic conduit (RMC) recognized by the NEC?

Accepted Answer

6 inches

Answer

3 inches

Answer

4 inches

Answer

5 inches

Question 6

When installing conductors in a raceway exposed to different temperatures, what NEC rule applies to prevent moisture condensation?

Accepted Answer

Seal the raceway at the point of temperature transition

Answer

Install vapor barriers at both ends

Answer

Use only dry-location rated conductors throughout

Answer

Install drain fittings at the lowest point

Question 7

Type NM cable is NOT permitted in which of the following applications?

Accepted Answer

Exposed industrial occupancies

Answer

Single-family dwellings

Answer

Multifamily dwellings not exceeding 3 floors above grade

Answer

Exposed in a residential garage