NEC Electrical 3 — Questions and Answers
Question 1: What is the maximum spacing between countertop receptacles along a dwelling kitchen counter?
- 24 inches
- 36 inches
- 48 inches (Correct answer)
- 72 inches
Correct answer: 48 inches
NEC 210.52(C) requires receptacles so no point along the counter is more than 24 inches from one, yielding 48-inch maximum spacing.
Question 2: What ampacity does an 8 AWG copper THHN conductor have at 75°C?
- 40 amps
- 50 amps (Correct answer)
- 55 amps
- 65 amps
Correct answer: 50 amps
Per NEC Table 310.16, 8 AWG copper at the 75°C column is rated 50 amps.
Question 3: Which NEC article covers wiring methods for hazardous (classified) locations?
- Article 100
- Article 250
- Article 500 (Correct answer)
- Article 700
Correct answer: Article 500
NEC Article 500 governs classification and wiring of hazardous (classified) locations.
Question 4: What is the minimum burial depth for a residential 120-volt circuit using direct-buried UF cable with GFCI protection at 20 amps or less?
- 6 inches
- 12 inches (Correct answer)
- 18 inches
- 24 inches
Correct answer: 12 inches
NEC Table 300.5 permits 12 inches of cover for GFCI-protected residential branch circuits of 20 amps or less.
Question 5: A continuous load must be calculated at what percentage of its value for conductor and overcurrent sizing?
- 80%
- 100%
- 125% (Correct answer)
- 150%
Correct answer: 125%
NEC 210.20(A) requires sizing at 125% of a continuous load.
Question 6: What device disconnects a circuit automatically when it detects an arcing fault?
- GFCI
- AFCI (Correct answer)
- Surge arrester
- Thermal relay
Correct answer: AFCI
An AFCI (Arc-Fault Circuit Interrupter) detects dangerous arcing and opens the circuit per NEC 210.12.
Question 7: What is the minimum working space depth in front of 120/240-volt equipment likely to be examined while energized (Condition 1)?
- 2 feet
- 3 feet (Correct answer)
- 3.5 feet
- 4 feet
Correct answer: 3 feet
NEC Table 110.26(A)(1) requires a minimum 3-foot working clearance for 0–150V Condition 1.
NEC Electrical 3
What is the maximum spacing between countertop receptacles along a dwelling kitchen counter?