LADWP Electrical Craft Helper Exam
2026/2027 Study Guide | LADWP Electrical
Craft Helper Practice Questions & Answers,
Detailed Rationales, Civil Service Exam Prep,
Electrical Trade Knowledge & Job Test Review
Question 1: What is the primary purpose of Lockout/Tagout (LOTO)
procedures when servicing electrical equipment?
A. To increase equipment operating efficiency
B. To prevent unexpected energization during maintenance
C. To reduce overall electricity consumption costs
D. To test the calibration of circuit breakers
CORRECT ANSWER: B. To prevent unexpected energization during
maintenance
Rationale: Lockout/Tagout procedures isolate energy sources and prevent
equipment from being unexpectedly energized while workers perform
maintenance or repairs, protecting personnel from electrical hazards.
Question 2: What is the unit of measurement for electrical resistance?
A. Volt
B. Ampere
C. Ohm
D. Watt
CORRECT ANSWER: C. Ohm
Rationale: Resistance is measured in ohms (Ω), representing opposition to
current flow. Voltage is measured in volts, current in amperes, and power in
watts.
Question 3: According to Ohm's Law, if a circuit has 120 volts and 20
ohms of resistance, what is the current?
A. 2 amperes
B. 4 amperes
C. 6 amperes
D. 20 amperes
CORRECT ANSWER: C. 6 amperes
,Rationale: Ohm's Law states I = V/R. Therefore, 120 volts ÷ 20 ohms = 6
amperes.
Question 4: Which material is considered the best conductor of
electricity among common wiring materials?
A. Aluminum
B. Copper
C. Steel
D. PVC
CORRECT ANSWER: B. Copper
Rationale: Copper has the highest electrical conductivity among common
wiring materials, exceeding aluminum and far surpassing non-conductors
like steel and PVC.
Question 5: What does an ammeter measure in an electrical circuit?
A. Voltage
B. Resistance
C. Current
D. Power
CORRECT ANSWER: C. Current
Rationale: An ammeter measures electrical current in amperes. It must be
connected in series with the circuit so all current flows through it.
Question 6: What is the total resistance of two 10-ohm resistors
connected in series?
A. 5 ohms
B. 10 ohms
C. 20 ohms
D. 100 ohms
CORRECT ANSWER: C. 20 ohms
Rationale: In a series circuit, total resistance is the sum of individual
resistances: 10 ohms + 10 ohms = 20 ohms.
Question 7: What is the total resistance of two 10-ohm resistors
connected in parallel?
,A. 5 ohms
B. 10 ohms
C. 20 ohms
D. 100 ohms
CORRECT ANSWER: A. 5 ohms
Rationale: In a parallel circuit, total resistance is less than the smallest
individual resistor. For two equal resistors, R_total = R/2 = 10/2 = 5 ohms.
Question 8: What is the standard frequency of alternating current (AC)
power in the United States?
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). Most other regions use 50 Hz.
Question 9: What is the primary purpose of electrical insulation on a
conductor?
A. To increase current flow
B. To prevent unintended electrical contact
C. To increase conductor temperature
D. To reduce conductor size
CORRECT ANSWER: B. To prevent unintended electrical contact
Rationale: Insulation electrically separates conductors from people,
equipment, and other conductive surfaces, preventing shocks and short
circuits.
Question 10: Which instrument is used to measure electrical
resistance?
A. Voltmeter
B. Ammeter
C. Ohmmeter
D. Tachometer
, CORRECT ANSWER: C. Ohmmeter
Rationale: An ohmmeter measures resistance in ohms. Before measuring
resistance, the circuit should generally be de-energized and isolated.
Question 11: What is the primary purpose of grounding an electrical
system?
A. To increase voltage output
B. To provide a path for fault current and protect people
C. To reduce wire size requirements
D. To improve power factor
CORRECT ANSWER: B. To provide a path for fault current and protect
people
Rationale: Grounding provides a low-resistance path for fault current,
enabling protective devices to operate and reducing shock hazards.
Question 12: What does the term "continuity" mean in an electrical
circuit?
A. The circuit is broken
B. There is a complete path for current flow
C. Voltage is zero
D. Resistance is infinite
CORRECT ANSWER: B. There is a complete path for current flow
Rationale: Continuity means an unbroken path for current exists between
test points. A broken circuit lacks continuity and shows infinite resistance.
Question 13: A 100-watt light bulb operates at 120 volts. What is the
approximate current draw?
A. 0.42 amperes
B. 0.83 amperes
C. 1.2 amperes
D. 2.0 amperes
CORRECT ANSWER: B. 0.83 amperes
Rationale: Using the power formula I = P/V: 100 watts ÷ 120 volts = 0.833
amperes.
2026/2027 Study Guide | LADWP Electrical
Craft Helper Practice Questions & Answers,
Detailed Rationales, Civil Service Exam Prep,
Electrical Trade Knowledge & Job Test Review
Question 1: What is the primary purpose of Lockout/Tagout (LOTO)
procedures when servicing electrical equipment?
A. To increase equipment operating efficiency
B. To prevent unexpected energization during maintenance
C. To reduce overall electricity consumption costs
D. To test the calibration of circuit breakers
CORRECT ANSWER: B. To prevent unexpected energization during
maintenance
Rationale: Lockout/Tagout procedures isolate energy sources and prevent
equipment from being unexpectedly energized while workers perform
maintenance or repairs, protecting personnel from electrical hazards.
Question 2: What is the unit of measurement for electrical resistance?
A. Volt
B. Ampere
C. Ohm
D. Watt
CORRECT ANSWER: C. Ohm
Rationale: Resistance is measured in ohms (Ω), representing opposition to
current flow. Voltage is measured in volts, current in amperes, and power in
watts.
Question 3: According to Ohm's Law, if a circuit has 120 volts and 20
ohms of resistance, what is the current?
A. 2 amperes
B. 4 amperes
C. 6 amperes
D. 20 amperes
CORRECT ANSWER: C. 6 amperes
,Rationale: Ohm's Law states I = V/R. Therefore, 120 volts ÷ 20 ohms = 6
amperes.
Question 4: Which material is considered the best conductor of
electricity among common wiring materials?
A. Aluminum
B. Copper
C. Steel
D. PVC
CORRECT ANSWER: B. Copper
Rationale: Copper has the highest electrical conductivity among common
wiring materials, exceeding aluminum and far surpassing non-conductors
like steel and PVC.
Question 5: What does an ammeter measure in an electrical circuit?
A. Voltage
B. Resistance
C. Current
D. Power
CORRECT ANSWER: C. Current
Rationale: An ammeter measures electrical current in amperes. It must be
connected in series with the circuit so all current flows through it.
Question 6: What is the total resistance of two 10-ohm resistors
connected in series?
A. 5 ohms
B. 10 ohms
C. 20 ohms
D. 100 ohms
CORRECT ANSWER: C. 20 ohms
Rationale: In a series circuit, total resistance is the sum of individual
resistances: 10 ohms + 10 ohms = 20 ohms.
Question 7: What is the total resistance of two 10-ohm resistors
connected in parallel?
,A. 5 ohms
B. 10 ohms
C. 20 ohms
D. 100 ohms
CORRECT ANSWER: A. 5 ohms
Rationale: In a parallel circuit, total resistance is less than the smallest
individual resistor. For two equal resistors, R_total = R/2 = 10/2 = 5 ohms.
Question 8: What is the standard frequency of alternating current (AC)
power in the United States?
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). Most other regions use 50 Hz.
Question 9: What is the primary purpose of electrical insulation on a
conductor?
A. To increase current flow
B. To prevent unintended electrical contact
C. To increase conductor temperature
D. To reduce conductor size
CORRECT ANSWER: B. To prevent unintended electrical contact
Rationale: Insulation electrically separates conductors from people,
equipment, and other conductive surfaces, preventing shocks and short
circuits.
Question 10: Which instrument is used to measure electrical
resistance?
A. Voltmeter
B. Ammeter
C. Ohmmeter
D. Tachometer
, CORRECT ANSWER: C. Ohmmeter
Rationale: An ohmmeter measures resistance in ohms. Before measuring
resistance, the circuit should generally be de-energized and isolated.
Question 11: What is the primary purpose of grounding an electrical
system?
A. To increase voltage output
B. To provide a path for fault current and protect people
C. To reduce wire size requirements
D. To improve power factor
CORRECT ANSWER: B. To provide a path for fault current and protect
people
Rationale: Grounding provides a low-resistance path for fault current,
enabling protective devices to operate and reducing shock hazards.
Question 12: What does the term "continuity" mean in an electrical
circuit?
A. The circuit is broken
B. There is a complete path for current flow
C. Voltage is zero
D. Resistance is infinite
CORRECT ANSWER: B. There is a complete path for current flow
Rationale: Continuity means an unbroken path for current exists between
test points. A broken circuit lacks continuity and shows infinite resistance.
Question 13: A 100-watt light bulb operates at 120 volts. What is the
approximate current draw?
A. 0.42 amperes
B. 0.83 amperes
C. 1.2 amperes
D. 2.0 amperes
CORRECT ANSWER: B. 0.83 amperes
Rationale: Using the power formula I = P/V: 100 watts ÷ 120 volts = 0.833
amperes.
