NEC Load Calculation Applications Questions and Answers

Question 1

An electrician is performing a standard load calculation for a 2,200 sq. ft. single-family dwelling.
What is the calculated load for the general lighting, small-appliance, and laundry circuits before any demand factors are applied?

Accepted Answer

11,100 VA

Answer

6,600 VA

Answer

4,500 VA

Answer

10,500 VA

Question 2

When calculating the feeder load for a group of continuous-duty motors, which of the following methods is required by NEC 430.24?

Accepted Answer

125% of the FLC of the largest motor, plus the sum of the FLCs of all other motors.

Answer

125% of the full-load current (FLC) of all motors combined.

Answer

100% of the FLC of all motors plus 25% of the largest motor's FLC.

Answer

100% of the FLC of all motors on the feeder.

Question 3

A feeder in a multi-family dwelling supplies ten 12 kW household electric ranges. Using the standard method and Column C of NEC Table 220.55, what is the calculated demand load for these ranges?

Accepted Answer

25 kW

Answer

120 kW

Answer

30 kW

Answer

40 kW

Question 4

For which of the following occupancies does NEC Table 220.42 allow a demand factor of 100% for the first 12,500 VA of general lighting load and 50% for the remainder?

Accepted Answer

Warehouse

Answer

Dwelling Unit

Answer

Hospital

Answer

Office Building

Question 5

An electrician is using the optional method (NEC 220.82) to calculate the service load for a single-family dwelling. After summing the general loads and all fastened-in-place appliances, the total connected load is 34,000 VA (excluding HVAC). What is the demand load for this portion of the calculation?

Accepted Answer

19,600 VA

Answer

13,600 VA

Answer

34,000 VA

Answer

24,000 VA

Question 6

When performing a standard load calculation for a dwelling unit, what is the minimum load in VA that must be used for a single household electric clothes dryer, unless the nameplate rating is larger?

Accepted Answer

5,000 VA

Answer

1,500 VA

Answer

4,500 VA

Answer

The nameplate rating only

An electrician is performing a standard load calculation for a 2,200 sq. ft. single-family dwelling.What is the calculated load for the general lighting, small-appliance, and laundry circuits before any demand factors are applied?

An electrician is performing a standard load calculation for a 2,200 sq. ft. single-family dwelling.
What is the calculated load for the general lighting, small-appliance, and laundry circuits before any demand factors are applied?