LADWP ELECTRICAL REPAIRER PRACTICE
EXAM WITH ACTUAL QUESTIONS AND
VERIFIED ANSWERS, PLUS EXPLAINED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED 100% PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
1.
A 120-volt resistive load draws 10 amperes of current. Assuming the
load is operating normally, what is its electrical resistance?
A. 6 Ω
B. 12 Ω
C. 120 Ω
D. 1,200 Ω
Answer: B. 12 Ω
Rationale: Ohm's law states that R = V ÷ I. Therefore, R = 120 V ÷ 10
A = 12 Ω. A repairer should be comfortable rearranging the basic
relationships among voltage, current, and resistance because these
calculations are fundamental to troubleshooting electrical equipment.
2.
An electrical repairer is troubleshooting a motor that has unexpectedly
stopped operating. Before removing covers or beginning internal
inspection, which action is the most appropriate first step?
A. Immediately measure resistance across the motor terminals
B. Replace the motor starter
C. Establish the equipment's electrical condition and follow the required
1
,isolation/lockout procedure
D. Apply a temporary jumper across the overload relay
Answer: C. Establish the equipment's electrical condition and follow
the required isolation/lockout procedure
Rationale: Safety and control of hazardous energy take priority over
troubleshooting speed. The repairer must establish what energy
sources are present, isolate them according to the applicable
procedure, and verify the condition before performing work. Jumping
protective devices or opening equipment without proper isolation can
create severe shock, arc-flash, or mechanical hazards.
3.
Three resistors of 10 Ω, 20 Ω, and 30 Ω are connected in series. What is
the total resistance?
A. 60 Ω
B. 15 Ω
C. 0.0167 Ω
D. 600 Ω
Answer: A. 60 Ω
Rationale: Series resistances add directly: Rₜ = 10 + 20 + 30 = 60 Ω. In
a series circuit, the same current flows through every component while
the source voltage is divided among the components according to their
resistance.
4.
Two 20-Ω resistors are connected in parallel across a voltage source.
What is their equivalent resistance?
2
,A. 40 Ω
B. 20 Ω
C. 10 Ω
D. 5 Ω
Answer: C. 10 Ω
Rationale: For two equal resistors in parallel, the equivalent resistance
is one-half the resistance of either resistor: 20 ÷ 2 = 10 Ω. Parallel
circuits provide multiple current paths, so their equivalent resistance is
less than the smallest individual branch resistance.
5.
A technician measures 480 V across a three-phase motor. One phase-to-
phase measurement is substantially lower than the other two. What
should this observation primarily suggest?
A. The motor must have excessive lubrication
B. A possible supply, connection, or winding problem exists
C. The motor is necessarily operating at its correct voltage
D. The motor bearings are definitely defective
Answer: B. A possible supply, connection, or winding problem exists
Rationale: Significant phase-voltage imbalance can result from supply
problems, loose or damaged connections, defective switching
equipment, or winding faults. A repairer should not immediately
condemn the motor; systematic testing is required to determine
whether the problem originates upstream or inside the motor.
6.
Which instrument is specifically designed to measure electrical
resistance?
3
, A. Ammeter
B. Voltmeter
C. Ohmmeter
D. Frequency meter
Answer: C. Ohmmeter
Rationale: An ohmmeter measures resistance in ohms. Resistance
measurements are generally made on a de-energized circuit because
the meter supplies its own small test voltage. Applying an ohmmeter to
an energized circuit can damage the instrument and produce unsafe
conditions.
7.
A motor nameplate indicates a full-load current of 18 A. During
operation, the motor repeatedly draws substantially more current while
mechanical load appears normal. Which condition should be
investigated first?
A. Possible mechanical overload, voltage problems, phase imbalance, or
winding abnormalities
B. Whether the enclosure needs painting
C. Whether the motor terminal box should be enlarged
D. Whether the shaft should be shortened
Answer: A. Possible mechanical overload, voltage problems, phase
imbalance, or winding abnormalities
Rationale: Excessive motor current can have several causes.
Mechanical overload, low or unbalanced voltage, phase loss, incorrect
connections, bearing problems, or damaged windings can all
contribute. Good troubleshooting isolates variables rather than
replacing the motor immediately.
4
EXAM WITH ACTUAL QUESTIONS AND
VERIFIED ANSWERS, PLUS EXPLAINED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED 100% PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
1.
A 120-volt resistive load draws 10 amperes of current. Assuming the
load is operating normally, what is its electrical resistance?
A. 6 Ω
B. 12 Ω
C. 120 Ω
D. 1,200 Ω
Answer: B. 12 Ω
Rationale: Ohm's law states that R = V ÷ I. Therefore, R = 120 V ÷ 10
A = 12 Ω. A repairer should be comfortable rearranging the basic
relationships among voltage, current, and resistance because these
calculations are fundamental to troubleshooting electrical equipment.
2.
An electrical repairer is troubleshooting a motor that has unexpectedly
stopped operating. Before removing covers or beginning internal
inspection, which action is the most appropriate first step?
A. Immediately measure resistance across the motor terminals
B. Replace the motor starter
C. Establish the equipment's electrical condition and follow the required
1
,isolation/lockout procedure
D. Apply a temporary jumper across the overload relay
Answer: C. Establish the equipment's electrical condition and follow
the required isolation/lockout procedure
Rationale: Safety and control of hazardous energy take priority over
troubleshooting speed. The repairer must establish what energy
sources are present, isolate them according to the applicable
procedure, and verify the condition before performing work. Jumping
protective devices or opening equipment without proper isolation can
create severe shock, arc-flash, or mechanical hazards.
3.
Three resistors of 10 Ω, 20 Ω, and 30 Ω are connected in series. What is
the total resistance?
A. 60 Ω
B. 15 Ω
C. 0.0167 Ω
D. 600 Ω
Answer: A. 60 Ω
Rationale: Series resistances add directly: Rₜ = 10 + 20 + 30 = 60 Ω. In
a series circuit, the same current flows through every component while
the source voltage is divided among the components according to their
resistance.
4.
Two 20-Ω resistors are connected in parallel across a voltage source.
What is their equivalent resistance?
2
,A. 40 Ω
B. 20 Ω
C. 10 Ω
D. 5 Ω
Answer: C. 10 Ω
Rationale: For two equal resistors in parallel, the equivalent resistance
is one-half the resistance of either resistor: 20 ÷ 2 = 10 Ω. Parallel
circuits provide multiple current paths, so their equivalent resistance is
less than the smallest individual branch resistance.
5.
A technician measures 480 V across a three-phase motor. One phase-to-
phase measurement is substantially lower than the other two. What
should this observation primarily suggest?
A. The motor must have excessive lubrication
B. A possible supply, connection, or winding problem exists
C. The motor is necessarily operating at its correct voltage
D. The motor bearings are definitely defective
Answer: B. A possible supply, connection, or winding problem exists
Rationale: Significant phase-voltage imbalance can result from supply
problems, loose or damaged connections, defective switching
equipment, or winding faults. A repairer should not immediately
condemn the motor; systematic testing is required to determine
whether the problem originates upstream or inside the motor.
6.
Which instrument is specifically designed to measure electrical
resistance?
3
, A. Ammeter
B. Voltmeter
C. Ohmmeter
D. Frequency meter
Answer: C. Ohmmeter
Rationale: An ohmmeter measures resistance in ohms. Resistance
measurements are generally made on a de-energized circuit because
the meter supplies its own small test voltage. Applying an ohmmeter to
an energized circuit can damage the instrument and produce unsafe
conditions.
7.
A motor nameplate indicates a full-load current of 18 A. During
operation, the motor repeatedly draws substantially more current while
mechanical load appears normal. Which condition should be
investigated first?
A. Possible mechanical overload, voltage problems, phase imbalance, or
winding abnormalities
B. Whether the enclosure needs painting
C. Whether the motor terminal box should be enlarged
D. Whether the shaft should be shortened
Answer: A. Possible mechanical overload, voltage problems, phase
imbalance, or winding abnormalities
Rationale: Excessive motor current can have several causes.
Mechanical overload, low or unbalanced voltage, phase loss, incorrect
connections, bearing problems, or damaged windings can all
contribute. Good troubleshooting isolates variables rather than
replacing the motor immediately.
4
