FREE Journeyman Electrician's Branch Circuits Questions and Answers

Question 1

If the computation for branch-circuits yields a value of 3.1, how many branch-circuits should be installed?

Accepted Answer

4

Answer

When calculating the number of branch circuits required, any fractional result must always be rounded up to the next whole number. This ensures that there is sufficient capacity to safely handle the calculated load, preventing overloading and ensuring compliance with electrical codes. Therefore, 3.1 branch circuits would necessitate installing 4 circuits.

Question 2

What exactly is a single branch circuit?

Accepted Answer

A branch circuit supplying only one utilization equipment

Answer

A single branch circuit, as defined by electrical codes like the National Electrical Code (NEC), is a circuit designed to supply power to only one piece of utilization equipment. This dedicated circuit ensures that the specific equipment receives adequate power without being affected by or affecting other loads, which is crucial for safety and proper operation of high-demand appliances.

Question 3

For twenty (20) baseboard heaters, each rated at 2,250 watts at 220-volts, single-phase, how many branch circuits of 40 amps, at 220-volts, are necessary?

Accepted Answer

7

Answer

First, calculate the total wattage: 20 heaters * 2,250 W/heater = 45,000 W. Next, determine the maximum continuous load for a 40-amp, 220-volt circuit, which is 40 A * 220 V * 0.80 (for continuous load) = 7,040 W. Finally, divide the total wattage by the circuit capacity: 45,000 W / 7,040 W/circuit = 6.39 circuits. Always round up for safety, so 7 branch circuits are necessary.

Question 4

Find the total area of a five-story building with 125 feet by 100 feet of outside space.

Accepted Answer

62,500 sq. ft.

Answer

To find the total area of a multi-story building, first calculate the area of a single floor: 125 feet * 100 feet = 12,500 square feet. Then, multiply this single-floor area by the number of stories: 12,500 square feet/floor * 5 stories = 62,500 square feet. This calculation provides the total floor area for lighting load calculations.

Question 5

Outside measurements of a swelling unit are 60 feet by 45 feet. How many 120-volt, 15-ampere general lighting brand circuits are need for the house?

Accepted Answer

5

Answer

First, calculate the total area: 60 ft * 45 ft = 2,700 sq ft. For general lighting in dwelling units, the NEC typically requires 3 VA per square foot, so the total lighting load is 2,700 sq ft * 3 VA/sq ft = 8,100 VA. A 120-volt, 15-ampere circuit can supply 120 V * 15 A = 1,800 VA. To find the number of circuits, divide the total load by the circuit capacity: 8,100 VA / 1,800 VA/circuit = 4.5 circuits. Always round up, so 5 general lighting branch circuits are needed.

Journeyman Electrician’s Exam Practice Test

Journeyman Electrician’s Exam Practice Test

FREE Journeyman Electrician's Branch Circuits Questions and Answers