PC Load Calculations and Service Entrance 1 — Questions and Answers
Question 1: Which NEC article covers service conductors and equipment for electrical services?
- Article 220
- Article 225
- Article 230 (Correct answer)
- Article 240
Correct answer: Article 230
NEC Article 230 covers service conductors and service entrance equipment including disconnecting means and overcurrent protection.
Question 2: Per NEC Table 220.12, what is the general lighting load volt-ampere value per square foot for commercial office buildings?
- 1 VA per sq ft
- 2 VA per sq ft
- 3.5 VA per sq ft (Correct answer)
- 5 VA per sq ft
Correct answer: 3.5 VA per sq ft
NEC Table 220.12 assigns a general lighting load of 3.5 VA per square foot for office buildings used in branch circuit and feeder calculations.
Question 3: What is the minimum number of 20-ampere small appliance branch circuits required in a residential kitchen per NEC 210.11(C)(1)?
- One 20A circuit
- Two 20A circuits (Correct answer)
- Three 20A circuits
- Four 20A circuits
Correct answer: Two 20A circuits
NEC 210.11(C)(1) mandates a minimum of two 20-ampere small appliance branch circuits to serve receptacle outlets in kitchen areas.
Question 4: Per NEC Table 220.42, what demand factor applies to the first 3,000 VA of residential lighting load?
- 50%
- 75%
- 100% (Correct answer)
- 125%
Correct answer: 100%
NEC Table 220.42 specifies a 100% demand factor for the first 3,000 VA of residential lighting load; demand factors drop for additional load.
Question 5: What is the minimum ampere rating for service entrance equipment in a new single-family dwelling per NEC 230.79(C)?
- 60 amperes
- 100 amperes (Correct answer)
- 150 amperes
- 200 amperes
Correct answer: 100 amperes
NEC 230.79(C) requires that the service disconnecting means for a single-family dwelling be rated at not less than 100 amperes.
Question 6: When sizing a feeder supplying multiple motors, how is the largest motor's FLA factored into the load calculation per NEC 430.24?
- Added at 100% of its FLA
- Added at 115% of its FLA
- Added at 125% of its FLA (Correct answer)
- Added at 150% of its FLA
Correct answer: Added at 125% of its FLA
NEC 430.24 requires that the largest motor's FLA be included at 125% when calculating the total feeder load for a group of motors.
PC Load Calculations and Service Entrance 1
Which NEC article covers service conductors and equipment for electrical services?