Journeyman Electrician’s Exam Journeyman Electrician's Service and Feeder Calculations 5

Question 1

For a 3,600 sq ft single-family dwelling using the standard method, how many 20A small appliance branch circuits are required, and what is their total VA load in the service calculation?

Accepted Answer

2 circuits, 3,000 VA

Answer

NEC 210.11(C)(1) requires at least two 20A small appliance circuits, each at 1,500 VA = 3,000 VA total per NEC 220.52.

Question 2

A service panel is supplied by a 500 kcmil aluminum feeder. What is the ampacity of this conductor using the 75°C column of NEC Table 310.15(B)(16)?

Accepted Answer

310 A

Answer

Per NEC Table 310.15(B)(16), 500 kcmil aluminum at 75°C has an ampacity of 310A.

Question 3

What additional load must be included in a service calculation for a dwelling that has a dedicated 20A laundry circuit per NEC 220.52(B)?

Accepted Answer

1,500 VA

Answer

NEC 220.52(B) requires 1,500 VA for each required laundry circuit in the service load calculation.

Question 4

When four current-carrying conductors are in a conduit, the ampacity adjustment factor per NEC 310.15(C)(1) is:

Accepted Answer

80%

Answer

NEC Table 310.15(C)(1) requires an 80% adjustment factor when 4–6 current-carrying conductors share a raceway.

Question 5

A service calculation for a 3,000 sq ft home includes general lighting, two small appliance circuits, one laundry circuit, a 12 kW range, and a 5 kW dryer. Using standard demand factors, what is the demand on the first 3,000W of the general lighting load?

Accepted Answer

100%

Answer

Per NEC Table 220.42, the first 3,000 VA of residential lighting load is taken at 100% demand.

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Journeyman Electrician’s Exam Journeyman Electrician's Service and Feeder Calculations 5