LADWP ELECTRICAL HELPER EXAM NEWEST
MAIN EXAM PRACTICE QUESTIONS 2025 -
2026| 170 ORIGINAL QUESTIONS &
ANSWERS FROM ACTUAL PAST PAPERS |
DETAILED RATIONALES | COMPLETE EXAM
PREP GRADED A+
1. A 120 V circuit has a resistance of 20 Ω. If the resistance remains constant,
what current will flow through the circuit?
A. 2 A
B. 4 A
C. 6 A
D. 8 A
Answer: B. 6 A
Using Ohm’s law, I = V/R = 120/20 = 6 A.
2. A 240 V load draws 15 A. Approximately how much power does the load
consume?
A. 1,600 W
B. 2,400 W
C. 3,600 W
D. 4,800 W
Answer: C. 3,600 W
Power is P = VI, so 240 × 15 = 3,600 W.
3. A technician measures 120 V from line to neutral and 0 V from neutral to
ground. What does this most directly indicate?
,A. The neutral is approximately at ground potential
B. The circuit has a shorted hot conductor
C. The neutral is disconnected
D. The line conductor is grounded
Answer: A. The neutral is approximately at ground potential
Under normal conditions, the grounded neutral conductor is maintained near
ground potential.
4. A 10 Ω resistor and a 20 Ω resistor are connected in series across a 120 V
source. What current flows through the circuit?
A. 2 A
B. 4 A
C. 6 A
D. 12 A
Answer: B. 4 A
The total resistance is 30 Ω. Therefore, I = 120/30 = 4 A.
5. Two 20 Ω resistors are connected in parallel. What is their equivalent
resistance?
A. 5 Ω
B. 10 Ω
C. 20 Ω
D. 40 Ω
Answer: B. 10 Ω
Equal resistors in parallel have an equivalent resistance equal to one-half of
either resistor.
6. A 120 V, 1,800 W heating element is energized. Approximately how much
current does it draw?
A. 7.5 A
B. 10 A
,C. 15 A
D. 20 A
Answer: C. 15 A
I = P/V = 1,800/120 = 15 A.
7. An electrical helper is instructed to work on a circuit that has been switched
off. Before touching the conductors, which action is most appropriate?
A. Assume the disconnect has isolated the circuit
B. Test for absence of voltage using an appropriate meter
C. Touch the conductor briefly with an insulated screwdriver
D. Remove the grounding conductor first
Answer: B. Test for absence of voltage using an appropriate meter
De-energization must be verified; opening a switch or disconnect alone does not
prove that conductors are electrically safe.
8. A circuit breaker repeatedly trips immediately after a motor is connected.
The first concern should be:
A. Excessive lighting load
B. An overcurrent condition or fault
C. Low ambient temperature
D. Excessive conductor length only
Answer: B. An overcurrent condition or fault
Repeated immediate tripping indicates that the protective device is detecting
excessive current or a fault condition.
9. A conductor has a resistance of 5 Ω and carries 4 A. What voltage drop
occurs across the conductor?
A. 0.8 V
B. 5 V
C. 20 V
D. 40 V
, Answer: C. 20 V
Voltage drop is V = IR = 4 × 5 = 20 V.
10.Which instrument is primarily used to measure electrical resistance?
A. Ammeter
B. Voltmeter
C. Ohmmeter
D. Frequency meter
Answer: C. Ohmmeter
An ohmmeter measures resistance in ohms and is normally used on a de-
energized circuit.
11.Before using an ohmmeter to check resistance in a circuit, what should
normally be done?
A. Increase the circuit voltage
B. Energize the circuit
C. De-energize and isolate the circuit
D. Connect the meter across a live source
Answer: C. De-energize and isolate the circuit
Resistance measurements should not normally be performed on an energized
circuit because the external voltage can damage the meter and create a shock
hazard.
12.A 120 V circuit contains a 60 W lamp. Approximately what current does the
lamp draw?
A. 0.25 A
B. 0.50 A
C. 1.0 A
D. 2.0 A
Answer: B. 0.50 A
MAIN EXAM PRACTICE QUESTIONS 2025 -
2026| 170 ORIGINAL QUESTIONS &
ANSWERS FROM ACTUAL PAST PAPERS |
DETAILED RATIONALES | COMPLETE EXAM
PREP GRADED A+
1. A 120 V circuit has a resistance of 20 Ω. If the resistance remains constant,
what current will flow through the circuit?
A. 2 A
B. 4 A
C. 6 A
D. 8 A
Answer: B. 6 A
Using Ohm’s law, I = V/R = 120/20 = 6 A.
2. A 240 V load draws 15 A. Approximately how much power does the load
consume?
A. 1,600 W
B. 2,400 W
C. 3,600 W
D. 4,800 W
Answer: C. 3,600 W
Power is P = VI, so 240 × 15 = 3,600 W.
3. A technician measures 120 V from line to neutral and 0 V from neutral to
ground. What does this most directly indicate?
,A. The neutral is approximately at ground potential
B. The circuit has a shorted hot conductor
C. The neutral is disconnected
D. The line conductor is grounded
Answer: A. The neutral is approximately at ground potential
Under normal conditions, the grounded neutral conductor is maintained near
ground potential.
4. A 10 Ω resistor and a 20 Ω resistor are connected in series across a 120 V
source. What current flows through the circuit?
A. 2 A
B. 4 A
C. 6 A
D. 12 A
Answer: B. 4 A
The total resistance is 30 Ω. Therefore, I = 120/30 = 4 A.
5. Two 20 Ω resistors are connected in parallel. What is their equivalent
resistance?
A. 5 Ω
B. 10 Ω
C. 20 Ω
D. 40 Ω
Answer: B. 10 Ω
Equal resistors in parallel have an equivalent resistance equal to one-half of
either resistor.
6. A 120 V, 1,800 W heating element is energized. Approximately how much
current does it draw?
A. 7.5 A
B. 10 A
,C. 15 A
D. 20 A
Answer: C. 15 A
I = P/V = 1,800/120 = 15 A.
7. An electrical helper is instructed to work on a circuit that has been switched
off. Before touching the conductors, which action is most appropriate?
A. Assume the disconnect has isolated the circuit
B. Test for absence of voltage using an appropriate meter
C. Touch the conductor briefly with an insulated screwdriver
D. Remove the grounding conductor first
Answer: B. Test for absence of voltage using an appropriate meter
De-energization must be verified; opening a switch or disconnect alone does not
prove that conductors are electrically safe.
8. A circuit breaker repeatedly trips immediately after a motor is connected.
The first concern should be:
A. Excessive lighting load
B. An overcurrent condition or fault
C. Low ambient temperature
D. Excessive conductor length only
Answer: B. An overcurrent condition or fault
Repeated immediate tripping indicates that the protective device is detecting
excessive current or a fault condition.
9. A conductor has a resistance of 5 Ω and carries 4 A. What voltage drop
occurs across the conductor?
A. 0.8 V
B. 5 V
C. 20 V
D. 40 V
, Answer: C. 20 V
Voltage drop is V = IR = 4 × 5 = 20 V.
10.Which instrument is primarily used to measure electrical resistance?
A. Ammeter
B. Voltmeter
C. Ohmmeter
D. Frequency meter
Answer: C. Ohmmeter
An ohmmeter measures resistance in ohms and is normally used on a de-
energized circuit.
11.Before using an ohmmeter to check resistance in a circuit, what should
normally be done?
A. Increase the circuit voltage
B. Energize the circuit
C. De-energize and isolate the circuit
D. Connect the meter across a live source
Answer: C. De-energize and isolate the circuit
Resistance measurements should not normally be performed on an energized
circuit because the external voltage can damage the meter and create a shock
hazard.
12.A 120 V circuit contains a 60 W lamp. Approximately what current does the
lamp draw?
A. 0.25 A
B. 0.50 A
C. 1.0 A
D. 2.0 A
Answer: B. 0.50 A
