NEC Electrical Assessment 2 — Questions and Answers
Question 1: Per NEC, what is the standard color used to identify the grounded (neutral) conductor in a 120/240V system?
- White or gray (Correct answer)
- Green
- Black
- Red
Correct answer: White or gray
The NEC requires grounded conductors to be identified by white or gray insulation or three white stripes.
Question 2: What is the minimum required headroom for working space about electrical equipment rated 600V or less?
- 6 ft 6 in (Correct answer)
- 5 ft
- 8 ft
- 7 ft
Correct answer: 6 ft 6 in
NEC 110.26(A)(3) requires a minimum headroom of 6 ft 6 in for working spaces about electrical equipment.
Question 3: A continuous load is defined in the NEC as a load where the maximum current is expected to continue for at least how long?
- 3 hours (Correct answer)
- 1 hour
- 30 minutes
- 6 hours
Correct answer: 3 hours
The NEC defines a continuous load as one whose maximum current continues for 3 hours or more.
Question 4: When sizing conductors and overcurrent protection for a continuous load, the load is multiplied by what factor?
- 125% (Correct answer)
- 100%
- 150%
- 80%
Correct answer: 125%
NEC requires the rating to be not less than 125% of the continuous load.
Question 5: What is the maximum number of current-carrying conductors allowed in a raceway before ampacity adjustment factors must be applied?
- 3 (Correct answer)
- 4
- 6
- 2
Correct answer: 3
Adjustment factors per NEC 310.15(C)(1) apply when more than 3 current-carrying conductors are in a raceway.
Question 6: Which conductor is NOT counted as a current-carrying conductor for ampacity adjustment in a normally balanced circuit?
- The neutral of a balanced 3-wire system (Correct answer)
- The ungrounded phase conductor
- An equipment grounding conductor that carries fault current
- A conductor feeding a single-phase load
Correct answer: The neutral of a balanced 3-wire system
A neutral carrying only the unbalanced current of a balanced multiwire circuit is not counted as current-carrying.
Question 7: What is the general ampacity of a 12 AWG copper conductor with 75°C insulation per NEC Table 310.16?
- 25 A (Correct answer)
- 20 A
- 30 A
- 15 A
Correct answer: 25 A
Table 310.16 lists 25 A for 12 AWG copper at 75°C, though the small-conductor rule may limit overcurrent protection.
NEC Electrical Assessment 2
Per NEC, what is the standard color used to identify the grounded (neutral) conductor in a 120/240V system?