IEC - Independent Electrical Contractors Wiring Methods and Materials Questions and Answers

Question 1

According to NEC Article 300, which of the following is an unacceptable method for supporting raceways in a commercial building with a suspended ceiling?

Accepted Answer

Attaching raceway supports directly to the suspended-ceiling grid.

Answer

Using independent support wires secured to the building structure.

Answer

Fastening raceway hangers to structural framing members above the ceiling.

Answer

Using a trapeze hanger supported by threaded rods anchored to the overhead structure.

Question 2

An electrician is installing Electrical Nonmetallic Tubing (ENT) in the walls of a new wood-frame residential construction. What is the maximum spacing interval required for securing and supporting the ENT?

Accepted Answer

3 feet

Answer

4.5 feet

Answer

5 feet

Answer

6 feet

Question 3

Which of the following wiring methods is permitted for use in a Class I, Division 1 hazardous location?

Accepted Answer

Threaded Intermediate Metal Conduit (IMC)

Answer

Electrical Metallic Tubing (EMT)

Answer

Electrical Nonmetallic Tubing (ENT)

Answer

Type NM Cable (Romex)

Question 4

When installing insulated equipment grounding conductors of size 6 AWG or smaller, what color(s) must the conductor's continuous outer finish be?

Accepted Answer

Green or green with one or more yellow stripes

Answer

White or Gray

Answer

Any color except white, gray, or green

Answer

Black or Red

Question 5

In a commercial installation, a metallic cable tray is used to support various power and control cables. To comply with NEC Article 392, the cable tray must be:

Accepted Answer

Bonded and connected to an effective equipment grounding conductor.

Answer

Filled to a maximum of 75% of its cross-sectional area.

Answer

Isolated from the building's structural steel.

Answer

Used exclusively for low-voltage cabling.

Question 6

Under which of the following conditions is a raceway permitted to be used as a means of support for a Class 2 thermostat cable?

Accepted Answer

The raceway contains the power supply conductors for the same equipment the thermostat controls.

Answer

The raceway is EMT smaller than 1 inch trade size.

Answer

The Class 2 cable is for a different system in the same room.

Answer

The raceway is nonmetallic and the cable is attached with plastic tie wraps.