Master Article 310 - Conductors for General Wiring

Question 1

A 240V electric vehicle charging station rated at 40A continuous load is installed in a residential garage. What is the minimum ampacity required for the branch circuit conductors per NEC 625.41?

1. 40A
2. 50A
3. 60A
4. 80A

Correct Answer: 50A

Why: Per NEC 625.41, continuous loads must be calculated at 125% of the rated load. 40A × 1.25 = 50A minimum ampacity required.

Question 2

According to NEC 210.8(A)(7), GFCI protection is required for all 125V through 250V receptacles installed in which location?

1. Attached garages only
2. All garages including detached
3. Carports only
4. Both garages and carports

Correct Answer: All garages including detached

Why: NEC 210.8(A)(7) requires GFCI protection for all receptacles in garages, including detached garages.

Question 3

A dwelling unit has a floor area of 2,400 sq ft. What is the minimum general lighting load calculation per NEC 220.12?

1. 7,200 VA
2. 8,400 VA
3. 9,600 VA
4. 12,000 VA

Correct Answer: 7,200 VA

Why: Per NEC 220.12, dwelling units require 3 VA per square foot for general lighting. 2,400 sq ft × 3 VA/sq ft = 7,200 VA.

Question 4

An industrial facility installs three 480V, 3-phase motors: 25 HP, 30 HP, and 40 HP. Using NEC Table 430.250, what is the full-load current for the 40 HP motor?

1. 52A
2. 65A
3. 77A
4. 104A

Correct Answer: 52A

Why: Per NEC Table 430.250, a 40 HP, 480V, 3-phase motor has a full-load current rating of 52 amperes.

Question 5

A commercial building requires EV charging infrastructure per NEC 625.9. For a building with 75 parking spaces, what is the minimum number of EV-ready parking spaces required?

1. 8
2. 15
3. 19
4. 25

Correct Answer: 19

Why: Per NEC 625.9, commercial buildings require 25% of parking spaces to be EV-ready when having 50 or more spaces. 75 × 0.25 = 18.75, rounded up to 19.