LADWP Electrical Craft Helper Exam -
Class Code 3799Exam Practice
Questions and Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
Questions 1–25
Question 1 — Basic Arithmetic
A crew has 8 rolls of cable, with 75 feet on each roll. How many feet of cable are
available?
A. 525 feet
B. 600 feet
C. 650 feet
D. 675 feet
Answer: B. 600 feet
Rationale: Multiply the number of rolls by the length of each roll: 8 × 75 = 600 feet.
Question 2 — Fractions
A cable is 48 feet long. A worker uses 3/8 of it. How many feet are used?
A. 12 feet
B. 15 feet
C. 18 feet
D. 24 feet
Answer: C. 18 feet
,Rationale: Calculate 48 × 3/8. Since 48 ÷ 8 = 6, and 6 × 3 = 18 feet.
Question 3 — Measuring Cable
A cable run requires 125 feet. An additional 10 feet is needed for termination
allowances. How much cable should be prepared?
A. 115 feet
B. 125 feet
C. 135 feet
D. 150 feet
Answer: C. 135 feet
Rationale: The required run is 125 feet, and 10 additional feet are needed for the
specified allowance. Therefore, 125 + 10 = 135 feet.
Question 4 — Ohm's Law
A 120-volt circuit has a resistance of 30 ohms. What current flows through the
circuit?
A. 2 A
B. 4 A
C. 30 A
D. 150 A
Answer: B. 4 A
Rationale: Ohm's law states I = V/R. Therefore, 120 ÷ 30 = 4 amperes.
Question 5 — Electrical Power
A 120-volt device draws 5 amperes. What is its electrical power?
A. 24 W
B. 125 W
C. 600 W
D. 625 W
Answer: C. 600 W
Rationale: Power is calculated as P = V × I. Thus, 120 × 5 = 600 watts.
,Question 6 — Conductors
Which material is commonly used as an electrical conductor because of its high
electrical conductivity?
A. Rubber
B. Glass
C. Copper
D. Porcelain
Answer: C. Copper
Rationale: Copper has high electrical conductivity and is widely used for electrical
conductors. Rubber, glass, and porcelain are generally used as insulating
materials.
Question 7 — Insulating Materials
Which material is primarily used as an electrical insulator?
A. Copper
B. Aluminum
C. Steel
D. Rubber
Answer: D. Rubber
Rationale: Rubber has high electrical resistance and is commonly used for
insulation and protective coverings. Conductive metals such as copper and
aluminum readily carry current.
Question 8 — Electrical Resistance
If resistance in a circuit increases while voltage remains constant, current will:
A. Increase
B. Decrease
C. Remain exactly twice as high
D. Become alternating current
Answer: B. Decrease
, Rationale: According to Ohm's law, I = V/R. With voltage held constant, increasing
resistance reduces current.
Question 9 — Series Circuit
In a simple series circuit, the current:
A. Is different through each component
B. Is zero at the source
C. Has the same value through each component
D. Exists only across the first component
Answer: C. Has the same value through each component
Rationale: A series circuit has one continuous current path, so the same current
flows through each component.
Question 10 — Parallel Circuit
In a basic parallel circuit, each branch connected across the same source has:
A. Different source voltages by definition
B. The same voltage across its terminals
C. Zero current
D. No electrical potential
Answer: B. The same voltage across its terminals
Rationale: Parallel branches connected between the same two nodes have the
same potential difference.
Question 11 — Voltmeter
A voltmeter is normally connected:
A. In series with the load
B. Across the points being measured
C. In place of the circuit fuse
D. Directly across a short circuit
Answer: B. Across the points being measured
Class Code 3799Exam Practice
Questions and Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
Questions 1–25
Question 1 — Basic Arithmetic
A crew has 8 rolls of cable, with 75 feet on each roll. How many feet of cable are
available?
A. 525 feet
B. 600 feet
C. 650 feet
D. 675 feet
Answer: B. 600 feet
Rationale: Multiply the number of rolls by the length of each roll: 8 × 75 = 600 feet.
Question 2 — Fractions
A cable is 48 feet long. A worker uses 3/8 of it. How many feet are used?
A. 12 feet
B. 15 feet
C. 18 feet
D. 24 feet
Answer: C. 18 feet
,Rationale: Calculate 48 × 3/8. Since 48 ÷ 8 = 6, and 6 × 3 = 18 feet.
Question 3 — Measuring Cable
A cable run requires 125 feet. An additional 10 feet is needed for termination
allowances. How much cable should be prepared?
A. 115 feet
B. 125 feet
C. 135 feet
D. 150 feet
Answer: C. 135 feet
Rationale: The required run is 125 feet, and 10 additional feet are needed for the
specified allowance. Therefore, 125 + 10 = 135 feet.
Question 4 — Ohm's Law
A 120-volt circuit has a resistance of 30 ohms. What current flows through the
circuit?
A. 2 A
B. 4 A
C. 30 A
D. 150 A
Answer: B. 4 A
Rationale: Ohm's law states I = V/R. Therefore, 120 ÷ 30 = 4 amperes.
Question 5 — Electrical Power
A 120-volt device draws 5 amperes. What is its electrical power?
A. 24 W
B. 125 W
C. 600 W
D. 625 W
Answer: C. 600 W
Rationale: Power is calculated as P = V × I. Thus, 120 × 5 = 600 watts.
,Question 6 — Conductors
Which material is commonly used as an electrical conductor because of its high
electrical conductivity?
A. Rubber
B. Glass
C. Copper
D. Porcelain
Answer: C. Copper
Rationale: Copper has high electrical conductivity and is widely used for electrical
conductors. Rubber, glass, and porcelain are generally used as insulating
materials.
Question 7 — Insulating Materials
Which material is primarily used as an electrical insulator?
A. Copper
B. Aluminum
C. Steel
D. Rubber
Answer: D. Rubber
Rationale: Rubber has high electrical resistance and is commonly used for
insulation and protective coverings. Conductive metals such as copper and
aluminum readily carry current.
Question 8 — Electrical Resistance
If resistance in a circuit increases while voltage remains constant, current will:
A. Increase
B. Decrease
C. Remain exactly twice as high
D. Become alternating current
Answer: B. Decrease
, Rationale: According to Ohm's law, I = V/R. With voltage held constant, increasing
resistance reduces current.
Question 9 — Series Circuit
In a simple series circuit, the current:
A. Is different through each component
B. Is zero at the source
C. Has the same value through each component
D. Exists only across the first component
Answer: C. Has the same value through each component
Rationale: A series circuit has one continuous current path, so the same current
flows through each component.
Question 10 — Parallel Circuit
In a basic parallel circuit, each branch connected across the same source has:
A. Different source voltages by definition
B. The same voltage across its terminals
C. Zero current
D. No electrical potential
Answer: B. The same voltage across its terminals
Rationale: Parallel branches connected between the same two nodes have the
same potential difference.
Question 11 — Voltmeter
A voltmeter is normally connected:
A. In series with the load
B. Across the points being measured
C. In place of the circuit fuse
D. Directly across a short circuit
Answer: B. Across the points being measured
