E2 Commercial Service Load Calculations 2 — Questions and Answers
Question 1: What is the unit lighting load per square foot for office occupancies per NEC Table 220.12?
- 1.0 VA/sq ft
- 3.5 VA/sq ft (Correct answer)
- 2.0 VA/sq ft
- 5.0 VA/sq ft
Correct answer: 3.5 VA/sq ft
NEC Table 220.12 specifies 3.5 VA per square foot as the unit lighting load for office occupancies.
Question 2: Per NEC 220.44, what demand factor applies to the portion of non-dwelling receptacle load that exceeds 10 kVA?
- 100%
- 75%
- 50% (Correct answer)
- 25%
Correct answer: 50%
NEC 220.44 permits a 50% demand factor on non-dwelling receptacle loads exceeding the first 10 kVA.
Question 3: What is the unit lighting load per square foot for a mercantile (retail store) occupancy per NEC Table 220.12?
- 1.5 VA/sq ft
- 2.0 VA/sq ft
- 3.0 VA/sq ft (Correct answer)
- 3.5 VA/sq ft
Correct answer: 3.0 VA/sq ft
NEC Table 220.12 lists 3 VA per square foot as the unit lighting load for mercantile occupancies.
Question 4: How many volt-amperes is assigned to each duplex receptacle outlet in a non-dwelling commercial occupancy per NEC 220.14(I)?
- 90 VA
- 120 VA
- 180 VA (Correct answer)
- 360 VA
Correct answer: 180 VA
NEC 220.14(I) assigns 180 VA to each single or multiple receptacle on one yoke in non-dwelling occupancies.
Question 5: For 'all other' commercial occupancies per NEC Table 220.42, what demand factor applies to lighting loads exceeding 50,000 VA?
- 100%
- 75%
- 50% (Correct answer)
- 35%
Correct answer: 50%
NEC Table 220.42 allows a 50% demand factor on lighting loads over 50,000 VA for most commercial occupancies.
Question 6: Which NEC article primarily governs branch circuit, feeder, and service load calculations for commercial buildings?
- Article 210
- Article 215
- Article 220 (Correct answer)
- Article 230
Correct answer: Article 220
NEC Article 220 specifically covers load calculation methods for branch circuits, feeders, and services.
Question 7: A 25,000 sq ft office building is being permitted. What is the minimum general lighting load before applying any demand factors?
- 50,000 VA
- 75,000 VA
- 87,500 VA (Correct answer)
- 125,000 VA
Correct answer: 87,500 VA
Office occupancies use 3.5 VA/sq ft per NEC Table 220.12, so 25,000 × 3.5 = 87,500 VA.
E2 Commercial Service Load Calculations 2
What is the unit lighting load per square foot for office occupancies per NEC Table 220.12?