Electrical Level 3 Module
1 Load Calculations and
Branch Feeder Circuits
1. What is the purpose of load calculations in electrical installations?
A. To estimate the cost of electrical equipment
B. To determine the size of conductors and overcurrent protection devices
C. To ensure compliance with aesthetic standards
D. To prevent overvoltage in the circuit
Answer: B
,2. What is the maximum allowable voltage drop for branch circuits under NEC
recommendations?
A. 3%
B. 5%
C. 10%
D. 15%
Answer: A
3. Which of the following is considered a continuous load?
A. Refrigerator
B. Lighting in a retail store
C. Kitchen outlets
D. Bathroom fan
Answer: B
4. When sizing branch circuit conductors for a continuous load, the load must be
multiplied by:
A. 80%
B. 100%
C. 125%
D. 150%
Answer: C
5. Which of the following formulas is used to calculate the total load in a branch
circuit?
A. Load (W) = Voltage (V) × Current (A)
B. Load (A) = Resistance (Ω) ÷ Voltage (V)
C. Load (A) = Power Factor × Voltage (V)
D. Load (V) = Current (A) × Power Factor
,Answer: A
6. A single-family dwelling has a calculated general lighting load of 3,000 watts.
According to the NEC, what is the standard voltage used for the calculation?
A. 120V
B. 208V
C. 240V
D. 277V
Answer: A
7. Which NEC table is commonly used to determine ampacities of conductors?
A. Table 310.16
B. Table 250.66
C. Table 430.52
D. Table 220.12
Answer: A
8. A branch circuit is feeding a motor with a full-load current of 20A. What is the
minimum conductor ampacity required for this circuit?
A. 20A
B. 24A
C. 25A
D. 30A
Answer: C (125% of 20A = 25A for motors)
9. What is the main function of a feeder circuit in an electrical system?
A. To supply power to appliances only
B. To deliver power from the service equipment to branch circuits
, C. To connect grounding electrodes to the service panel
D. To manage short circuits within the branch circuit
Answer: B
10. When calculating demand load for a range in a residential dwelling, which NEC
table should be referenced?
A. Table 310.15(B)(16)
B. Table 220.55
C. Table 250.122
D. Table 430.248
Answer: B
11. What is the minimum branch circuit size for a 1,500-watt, 120-volt space heater?
A. 10A
B. 15A
C. 20A
D. 30A
Answer: C
(1,500W ÷ 120V = 12.5A, and the next standard circuit size is 20A.)
12. When calculating the load for small appliance branch circuits in a dwelling unit,
how many watts per circuit are typically used?
A. 1,000W
B. 1,500W
C. 2,000W
D. 3,000W
Answer: C
1 Load Calculations and
Branch Feeder Circuits
1. What is the purpose of load calculations in electrical installations?
A. To estimate the cost of electrical equipment
B. To determine the size of conductors and overcurrent protection devices
C. To ensure compliance with aesthetic standards
D. To prevent overvoltage in the circuit
Answer: B
,2. What is the maximum allowable voltage drop for branch circuits under NEC
recommendations?
A. 3%
B. 5%
C. 10%
D. 15%
Answer: A
3. Which of the following is considered a continuous load?
A. Refrigerator
B. Lighting in a retail store
C. Kitchen outlets
D. Bathroom fan
Answer: B
4. When sizing branch circuit conductors for a continuous load, the load must be
multiplied by:
A. 80%
B. 100%
C. 125%
D. 150%
Answer: C
5. Which of the following formulas is used to calculate the total load in a branch
circuit?
A. Load (W) = Voltage (V) × Current (A)
B. Load (A) = Resistance (Ω) ÷ Voltage (V)
C. Load (A) = Power Factor × Voltage (V)
D. Load (V) = Current (A) × Power Factor
,Answer: A
6. A single-family dwelling has a calculated general lighting load of 3,000 watts.
According to the NEC, what is the standard voltage used for the calculation?
A. 120V
B. 208V
C. 240V
D. 277V
Answer: A
7. Which NEC table is commonly used to determine ampacities of conductors?
A. Table 310.16
B. Table 250.66
C. Table 430.52
D. Table 220.12
Answer: A
8. A branch circuit is feeding a motor with a full-load current of 20A. What is the
minimum conductor ampacity required for this circuit?
A. 20A
B. 24A
C. 25A
D. 30A
Answer: C (125% of 20A = 25A for motors)
9. What is the main function of a feeder circuit in an electrical system?
A. To supply power to appliances only
B. To deliver power from the service equipment to branch circuits
, C. To connect grounding electrodes to the service panel
D. To manage short circuits within the branch circuit
Answer: B
10. When calculating demand load for a range in a residential dwelling, which NEC
table should be referenced?
A. Table 310.15(B)(16)
B. Table 220.55
C. Table 250.122
D. Table 430.248
Answer: B
11. What is the minimum branch circuit size for a 1,500-watt, 120-volt space heater?
A. 10A
B. 15A
C. 20A
D. 30A
Answer: C
(1,500W ÷ 120V = 12.5A, and the next standard circuit size is 20A.)
12. When calculating the load for small appliance branch circuits in a dwelling unit,
how many watts per circuit are typically used?
A. 1,000W
B. 1,500W
C. 2,000W
D. 3,000W
Answer: C
