TL;DR
Master electrical load calculations including demand factors and service sizing. Accurate load calculations are essential for safe electrical design and a major exam topic.
Free Commercial Load Calculations Practice Questions
Master Electrician License Exam · Advanced Calculations
This module covers Commercial Load Calculations as part of the Advanced Calculations section, testing your understanding of core concepts and their practical application.
| Exam | Master Electrician License Exam |
| Pass Rate | 45% |
| Duration | 300 minutes |
| Module | Commercial Load Calculations |
Why Commercial Load Calculations matters
Commercial Load Calculations is one of the most tested areas because medication errors are among the most preventable causes of patient harm.
Sample Practice Questions (5)
1. A 20,000 sq ft office building has 100 general-purpose receptacles and 40 linear feet of show window. After applying NEC demand factors (Table 220.42 for lighting, Table 220.44 for receptacles), what is the demand load for the combined lighting and receptacle loads? (Lighting: first 10 kVA at 100%, remainder at 50%; Receptacles: first 10 kVA at 100%, remainder at 50%)
- 62,500 VA
- 78,000 VA
- 55,000 VA
- 96,000 VA
2. A restaurant kitchen has 6 pieces of commercial cooking equipment with a total nameplate rating of 80 kVA. Per NEC Table 220.56, what is the calculated demand load for this kitchen equipment?
- 52,000 VA
- 80,000 VA
- 44,000 VA
- 40,000 VA
3. A 15,000 sq ft office building is served by a 208Y/120V, 3-phase service. The total demand load (after all demand factors) is calculated as 95,000 VA. What is the minimum ampere rating of the service entrance conductors?
- 264 amperes
- 457 amperes
- 396 amperes
- 792 amperes
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Start practicing free →4. A 10,000 sq ft office building has general lighting, 30 receptacle outlets, and 20 linear feet of show window. What is the total calculated lighting and receptacle load before demand factors? (Use 180 VA per receptacle)
- 44,400 VA
- 35,000 VA
- 40,400 VA
- 39,000 VA
5. A retail store measures 5,000 sq ft. Per NEC Table 220.12, what VA per square foot applies to a retail store (other than listed exceptions)?
- 1.5 VA per square foot
- 3.5 VA per square foot
- 2.0 VA per square foot
- 4.0 VA per square foot
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