An electrical schedule shows a panel with a 200-amp main breaker and lists 40 circuits. If each circuit breaker is rated at 20 amps, what is the demand factor being applied?
Correct Answer
A) 25%
Total circuit capacity = 40 circuits × 20 amps = 800 amps. Panel capacity = 200 amps. Demand factor = 200/800 = 0.25 or 25%.
Why This Is the Correct Answer
The demand factor is calculated by dividing the actual panel capacity by the total connected load capacity. With 40 circuits at 20 amps each, the total connected load is 800 amps, but the panel only has a 200-amp main breaker capacity. This gives us 200 ÷ 800 = 0.25 or 25%, which reflects the realistic expectation that not all circuits will operate at full capacity simultaneously.
Why the Other Options Are Wrong
Option C: 50%
100% would mean no demand factor is applied, requiring the panel capacity to equal the total circuit capacity (800 amps), which clearly doesn't match the 200-amp main breaker shown.
Option D: 75%
50% would result from incorrectly calculating the demand factor, possibly by confusing the relationship between panel capacity and circuit capacity or using wrong values in the calculation.
Memory Technique
Think 'Demand = Delivered ÷ Designed' - the actual delivered capacity (panel) divided by the designed total capacity (all circuits)
Reference Hint
NEC Article 220 - Branch-Circuit, Feeder, and Service Load Calculations, specifically sections on demand factors and load calculations
More Project Mgmt Questions
What is the minimum R-value required for wall insulation in Florida Climate Zone 2?
A subcontractor brings a new chemical product to your jobsite. Under the Globally Harmonized System (GHS), what information must be immediately available to workers?
A construction site has a trench that is 8 feet deep in Type B soil. What is the maximum allowable slope ratio for the trench walls without protective systems?
What is the maximum recommended spacing between drywall screws when attaching to wood studs?
Your crew discovers suspected asbestos-containing materials during a renovation project. What is the first action you should take?
A scaffold platform is 12 feet long and 5 feet wide. If the maximum load capacity is 25 pounds per square foot, what is the total weight capacity of this platform?
Which CSI MasterFormat Division would contain specifications for fire-stopping and firesafing materials?
In tilt-up concrete construction, what is the primary advantage of this method over conventional cast-in-place construction?
Which OSHA standard specifically addresses construction industry safety and health regulations?
A structural drawing shows a beam labeled 'W12x26'. What does the '26' represent?
People Also Study
Business & Financial Management
120 questions · 70% to pass
Contract Administration
60 questions · 70% to pass
Related Study Resources
Previous Question
Calculate the volume of concrete needed for a rectangular foundation wall that is 100 feet long, 8 inches thick, and 8 feet high.
Next Question
You discover a trench cave-in has occurred with a worker trapped. The trench is 12 feet deep in unstable soil. What is your immediate priority?