NJATC Load Calculations 1 — Questions and Answers
Question 1: According to NEC Table 220.12, what is the general lighting load in volt-amperes per square foot for a dwelling unit?
- 1 VA/sq ft
- 2 VA/sq ft
- 3 VA/sq ft (Correct answer)
- 4 VA/sq ft
Correct answer: 3 VA/sq ft
NEC Table 220.12 specifies 3 VA per square foot as the general lighting load for dwelling units.
Question 2: How many 20-ampere small appliance branch circuits are required by the NEC in the kitchen, pantry, breakfast room, and dining room of a dwelling unit?
- One
- Two (Correct answer)
- Three
- Four
Correct answer: Two
NEC 210.11(C)(1) requires at least two 20-ampere small appliance branch circuits for these areas of a dwelling.
Question 3: What demand factor is applied to the first 3,000 VA of general lighting load in a dwelling unit per NEC Table 220.42?
- 100% (Correct answer)
- 75%
- 50%
- 35%
Correct answer: 100%
NEC Table 220.42 specifies a 100% demand factor for the first 3,000 VA of general lighting and receptacle loads in a dwelling unit.
Question 4: Per NEC Table 220.55 Column C, what is the permitted demand load for a single household electric range rated at 12 kW or less?
- 6 kW
- 8 kW (Correct answer)
- 10 kW
- 12 kW
Correct answer: 8 kW
NEC Table 220.55 Column C permits an 8 kW demand load for a single household range rated at 12 kW or less.
Question 5: What minimum load in volt-amperes must be included per NEC 220.52(A) for each laundry branch circuit in a dwelling unit?
- 1,000 VA
- 1,500 VA (Correct answer)
- 2,000 VA
- 2,500 VA
Correct answer: 1,500 VA
NEC 220.52(A) requires a minimum 1,500 VA load for each laundry branch circuit included in a dwelling unit calculation.
Question 6: Per NEC 220.60, when can the smaller of two non-coincident loads (such as heating and cooling) be omitted from a dwelling service calculation?
- When the heating load exceeds 5 kW
- When both systems will not operate simultaneously (Correct answer)
- When the AC load is greater than heating
- When heating exceeds AC load by more than 50%
Correct answer: When both systems will not operate simultaneously
NEC 220.60 permits omitting the smaller non-coincident load when it is unlikely the two systems will operate at the same time.
Question 7: For a 240-volt, single-phase circuit supplying a 30-ampere load, what is the calculated apparent power?
- 3,600 VA
- 4,800 VA
- 6,000 VA
- 7,200 VA (Correct answer)
Correct answer: 7,200 VA
Apparent power = Voltage × Current = 240V × 30A = 7,200 VA for a single-phase circuit.
NJATC Load Calculations 1
According to NEC Table 220.12, what is the general lighting load in volt-amperes per square foot for a dwelling unit?