CEA Wiring Methods and Materials Questions and Answers

Question 1

According to the NEC, what is the required color code for the insulation of a grounded conductor (neutral) in a 120/240V system for conductors size 6 AWG or smaller?

Accepted Answer

White or gray.

Answer

NEC Section 200.6(A) specifies that an insulated grounded conductor of 6 AWG or smaller shall be identified by a continuous white or gray outer finish. Green is reserved for equipment grounding conductors, while other colors like black, red, and blue are typically used for ungrounded (hot) conductors.

Question 2

An apprentice is installing a run of 1/2-inch Electrical Metallic Tubing (EMT) on a long, straight wall. According to the NEC, what is the maximum distance allowed between supports for this EMT run?

Accepted Answer

10 feet

Answer

NEC Section 358.30(A) requires that EMT be securely fastened in place at least every 10 feet. Additionally, it must be supported within 3 feet of each outlet box, junction box, device box, cabinet, or other tubing termination.

Question 3

An apprentice needs to select a cable for a residential branch circuit that will be run concealed within a dry, interior wall. Which of the following cable types is most commonly used and permitted for this application?

Accepted Answer

Type NM (Nonmetallic-Sheathed Cable)

Answer

NEC Article 334 permits the use of Type NM cable for both exposed and concealed work in normally dry locations, which makes it the standard for interior residential wiring. Type UF is for underground/direct burial, Type SE is primarily for service-entrance conductors, and Type TC is restricted to use in cable trays.

Question 4

An apprentice is laying out receptacle outlets for the living room of a new single-family dwelling. According to the NEC general provisions for receptacle placement along walls, no point measured horizontally along the floor line in any wall space should be more than how far from a receptacle outlet?

Accepted Answer

6 feet

Answer

NEC Section 210.52(A)(1) states that receptacles shall be installed so that no point measured horizontally along the floor line in any wall space is more than 6 feet from a receptacle outlet. This rule ensures that a standard 6-foot appliance cord can reach an outlet from any point along the wall, effectively placing receptacles a maximum of 12 feet apart.

Question 5

What is the primary purpose of the main bonding jumper in a service panel?

Accepted Answer

To provide a connection between the grounded service conductor (neutral) and the equipment grounding conductor(s).

Answer

The main bonding jumper provides the critical low-impedance path between the grounded conductor (neutral) and the equipment grounding conductor system at the service disconnect. This connection is essential for creating an effective ground-fault current path, which allows the overcurrent device (breaker or fuse) to operate quickly during a ground-fault.

(CEA) Certified Electrical Apprentice Practice Test

(CEA) Certified Electrical Apprentice Practice Test

CEA Wiring Methods and Materials Questions and Answers