LADWP Electrical Craft Helper Exam 2026/2027 – ACTUAL-Style Practice
Questions & Answers, Los Angeles Department of Water and Power Civil
Service Test 3799 Prep, Electrical Fundamentals, Basic Mathematics,
Mechanical Aptitude, Judgment and Decision Making, Reading
Comprehension, Work Instructions and Street Maps, Hand and Power
Tools, Electrical Cables and Wire Measurement, Common Knots, Test
Equipment, Workplace Safety, Tool Handling & Detailed Explanations
Question 1: What is the primary function of an electrical circuit?
A. To increase wire temperature
B. To provide a complete path for current flow
C. To prevent all voltage from reaching a load
D. To eliminate resistance
CORRECT ANSWER: B. To provide a complete path for current flow
Rationale: An electrical circuit must provide a continuous path from the
source through the load and back to the source. If the path is interrupted,
current cannot flow through the complete circuit .
Question 2: Which unit is used to measure electrical current?
A. Volt
B. Ohm
C. Ampere
D. Watt
CORRECT ANSWER: C. Ampere
Rationale: Electrical current is measured in amperes, commonly
abbreviated as amps or A. Voltage is measured in volts, resistance in ohms,
and power in watts .
Question 3: Which instrument is normally used to measure voltage?
A. Ammeter
B. Voltmeter
C. Ohmmeter
D. Watt-hour meter
CORRECT ANSWER: B. Voltmeter
,Rationale: A voltmeter measures electrical potential difference between
two points. When measuring voltage with a typical multimeter, the meter is
connected across the points being tested rather than placed in series with
the circuit .
Question 4: According to Ohm's law, which formula represents the
relationship between voltage, current, and resistance?
A. V = I × R
B. V = I ÷ R
C. V = R ÷ I
D. V = I + R
CORRECT ANSWER: A. V = I × R
Rationale: Ohm's law states that voltage equals current multiplied by
resistance. The relationship can also be rearranged to determine current or
resistance .
Question 5: If a 120-volt load has a resistance of 20 ohms,
approximately how much current flows through it?
A. 2 A
B. 4 A
C. 6 A
D. 12 A
CORRECT ANSWER: C. 6 A
Rationale: Using Ohm's law, I = V / R. Dividing 120 volts by 20 ohms gives 6
amperes. This calculation illustrates how current depends on both applied
voltage and circuit resistance .
Question 6: What happens to current in a circuit if resistance increases
while voltage remains constant?
A. Current increases
B. Current decreases
C. Current remains exactly the same
D. Current becomes alternating current
CORRECT ANSWER: B. Current decreases
,Rationale: According to Ohm's law, current equals voltage divided by
resistance. Therefore, when voltage remains constant, increasing
resistance causes current to decrease .
Question 7: What is the main function of a circuit breaker?
A. To increase circuit voltage
B. To store electrical energy
C. To interrupt a circuit when excessive current occurs
D. To improve wire conductivity
CORRECT ANSWER: C. To interrupt a circuit when excessive current
occurs
Rationale: A circuit breaker is an overcurrent protective device. It opens the
circuit when current exceeds its designed operating limits, helping protect
conductors and equipment from overheating and potential damage .
Question 8: What is the purpose of an equipment grounding conductor?
A. To normally carry load current
B. To provide a low-impedance path for fault current
C. To increase circuit resistance
D. To replace the circuit neutral in every application
CORRECT ANSWER: B. To provide a low-impedance path for fault
current
Rationale: The equipment grounding conductor provides a conductive path
for fault current back toward the source so that protective devices can
operate promptly. It is not intended to carry normal load current .
Question 9: Which color is commonly associated with the grounded
conductor in many U.S. electrical systems?
A. Green
B. White or gray
C. Red
D. Black
CORRECT ANSWER: B. White or gray
, Rationale: In U.S. electrical systems, the grounded conductor (neutral) is
typically identified by white or gray insulation, while green is used for
equipment grounding conductors .
Question 10: What is the standard frequency of alternating current in
North America?
A. 25 Hz
B. 50 Hz
C. 60 Hz
D. 100 Hz
CORRECT ANSWER: C. 60 Hz
Rationale: The standard AC frequency in North America is 60 cycles per
second (60 Hz). U.S. utility grids operate at this frequency, whereas many
other countries use 50 Hz .
Question 11: Direct current (DC) flows in which manner?
A. Periodically back and forth
B. In one direction only
C. Only through transformers
D. Randomly
CORRECT ANSWER: B. In one direction only
Rationale: Direct current flows in one direction only. Examples include
battery-powered circuits and solar panels. Alternating current periodically
reverses direction .
Question 12: What is the unit of electrical resistance?
A. Volt
B. Ampere
C. Ohm
D. Watt
CORRECT ANSWER: C. Ohm
Rationale: Resistance is measured in ohms (Ω), as defined by Ohm's Law. A
volt measures electrical pressure, an ampere measures current flow, and a
watt measures power .
Questions & Answers, Los Angeles Department of Water and Power Civil
Service Test 3799 Prep, Electrical Fundamentals, Basic Mathematics,
Mechanical Aptitude, Judgment and Decision Making, Reading
Comprehension, Work Instructions and Street Maps, Hand and Power
Tools, Electrical Cables and Wire Measurement, Common Knots, Test
Equipment, Workplace Safety, Tool Handling & Detailed Explanations
Question 1: What is the primary function of an electrical circuit?
A. To increase wire temperature
B. To provide a complete path for current flow
C. To prevent all voltage from reaching a load
D. To eliminate resistance
CORRECT ANSWER: B. To provide a complete path for current flow
Rationale: An electrical circuit must provide a continuous path from the
source through the load and back to the source. If the path is interrupted,
current cannot flow through the complete circuit .
Question 2: Which unit is used to measure electrical current?
A. Volt
B. Ohm
C. Ampere
D. Watt
CORRECT ANSWER: C. Ampere
Rationale: Electrical current is measured in amperes, commonly
abbreviated as amps or A. Voltage is measured in volts, resistance in ohms,
and power in watts .
Question 3: Which instrument is normally used to measure voltage?
A. Ammeter
B. Voltmeter
C. Ohmmeter
D. Watt-hour meter
CORRECT ANSWER: B. Voltmeter
,Rationale: A voltmeter measures electrical potential difference between
two points. When measuring voltage with a typical multimeter, the meter is
connected across the points being tested rather than placed in series with
the circuit .
Question 4: According to Ohm's law, which formula represents the
relationship between voltage, current, and resistance?
A. V = I × R
B. V = I ÷ R
C. V = R ÷ I
D. V = I + R
CORRECT ANSWER: A. V = I × R
Rationale: Ohm's law states that voltage equals current multiplied by
resistance. The relationship can also be rearranged to determine current or
resistance .
Question 5: If a 120-volt load has a resistance of 20 ohms,
approximately how much current flows through it?
A. 2 A
B. 4 A
C. 6 A
D. 12 A
CORRECT ANSWER: C. 6 A
Rationale: Using Ohm's law, I = V / R. Dividing 120 volts by 20 ohms gives 6
amperes. This calculation illustrates how current depends on both applied
voltage and circuit resistance .
Question 6: What happens to current in a circuit if resistance increases
while voltage remains constant?
A. Current increases
B. Current decreases
C. Current remains exactly the same
D. Current becomes alternating current
CORRECT ANSWER: B. Current decreases
,Rationale: According to Ohm's law, current equals voltage divided by
resistance. Therefore, when voltage remains constant, increasing
resistance causes current to decrease .
Question 7: What is the main function of a circuit breaker?
A. To increase circuit voltage
B. To store electrical energy
C. To interrupt a circuit when excessive current occurs
D. To improve wire conductivity
CORRECT ANSWER: C. To interrupt a circuit when excessive current
occurs
Rationale: A circuit breaker is an overcurrent protective device. It opens the
circuit when current exceeds its designed operating limits, helping protect
conductors and equipment from overheating and potential damage .
Question 8: What is the purpose of an equipment grounding conductor?
A. To normally carry load current
B. To provide a low-impedance path for fault current
C. To increase circuit resistance
D. To replace the circuit neutral in every application
CORRECT ANSWER: B. To provide a low-impedance path for fault
current
Rationale: The equipment grounding conductor provides a conductive path
for fault current back toward the source so that protective devices can
operate promptly. It is not intended to carry normal load current .
Question 9: Which color is commonly associated with the grounded
conductor in many U.S. electrical systems?
A. Green
B. White or gray
C. Red
D. Black
CORRECT ANSWER: B. White or gray
, Rationale: In U.S. electrical systems, the grounded conductor (neutral) is
typically identified by white or gray insulation, while green is used for
equipment grounding conductors .
Question 10: What is the standard frequency of alternating current in
North America?
A. 25 Hz
B. 50 Hz
C. 60 Hz
D. 100 Hz
CORRECT ANSWER: C. 60 Hz
Rationale: The standard AC frequency in North America is 60 cycles per
second (60 Hz). U.S. utility grids operate at this frequency, whereas many
other countries use 50 Hz .
Question 11: Direct current (DC) flows in which manner?
A. Periodically back and forth
B. In one direction only
C. Only through transformers
D. Randomly
CORRECT ANSWER: B. In one direction only
Rationale: Direct current flows in one direction only. Examples include
battery-powered circuits and solar panels. Alternating current periodically
reverses direction .
Question 12: What is the unit of electrical resistance?
A. Volt
B. Ampere
C. Ohm
D. Watt
CORRECT ANSWER: C. Ohm
Rationale: Resistance is measured in ohms (Ω), as defined by Ohm's Law. A
volt measures electrical pressure, an ampere measures current flow, and a
watt measures power .
