LADWP ELECTRICAL HELPER 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 incandescent lamp draws 2 amperes of current when
operating normally. What is the approximate resistance of the lamp
while operating?
A. 30 Ω
B. 60 Ω
C. 120 Ω
D. 240 Ω
Answer: B. 60 Ω
Rationale: Ohm’s law states that R = V ÷ I. Therefore, 120 V ÷ 2 A =
60 Ω. The resistance of an incandescent lamp changes with
temperature, so this represents its approximate operating resistance
rather than necessarily its cold resistance.
2. An electrical helper is instructed to work on a circuit that has been
de-energized. Which procedure provides the most appropriate
protection against accidental energization?
A. Turn the switch off and begin working immediately.
B. Remove the circuit's fuse and place it in a pocket.
C. Lockout/tagout the energy source and verify absence of voltage with
an appropriate tester.
D. Ask another employee whether the circuit is energized.
1
,Answer: C. Lockout/tagout the energy source and verify absence of
voltage with an appropriate tester.
Rationale: Lockout/tagout prevents unexpected energization while
work is being performed. Testing for absence of voltage is also
essential because a switch in the OFF position alone does not prove
that the conductors are electrically safe.
3. Which instrument is specifically designed to measure electrical
potential difference between two points?
A. Voltmeter
B. Ammeter
C. Ohmmeter
D. Megohmmeter only
Answer: A. Voltmeter
Rationale: A voltmeter measures voltage, or electrical potential
difference, between two points. It is normally connected in parallel
with the portion of the circuit being measured. An ammeter measures
current, while an ohmmeter measures resistance.
4. Why is an ammeter normally connected in series with a circuit
when measuring current?
A. It creates a high-resistance path that prevents current flow.
B. It allows the entire circuit current to pass through the meter.
C. It measures the voltage drop across the circuit.
D. It eliminates the need for circuit protection.
Answer: B. It allows the entire circuit current to pass through the
meter.
2
,Rationale: An ammeter is designed with very low internal resistance
and is inserted in series so the current being measured flows through
it. Connecting an ordinary ammeter directly across a voltage source
can create a near-short circuit and can damage the meter or create a
hazardous condition.
5. A circuit contains a 20-ohm load connected to a 120-volt source.
Approximately how much current flows through the load?
A. 0.17 A
B. 2 A
C. 6 A
D. 24 A
Answer: C. 6 A
Rationale: Using Ohm’s law, I = V ÷ R. Thus, 120 V ÷ 20 Ω = 6 A.
This calculation assumes the load behaves approximately as a resistive
load under the stated conditions.
6. Which electrical quantity is measured in amperes?
A. Resistance
B. Power
C. Current
D. Voltage
Answer: C. Current
Rationale: The ampere, or amp, is the SI unit of electric current.
Voltage is measured in volts, resistance in ohms, and electrical power
in watts.
3
, 7. An electrical worker finds that the insulation on a conductor has
been cut deeply enough to expose the metal conductor. What is the
safest action?
A. Wrap it with ordinary adhesive tape and continue working.
B. Bend the damaged section away from other conductors.
C. Report the damage and have the conductor properly repaired or
replaced before use.
D. Spray the conductor with insulating lubricant.
Answer: C. Report the damage and have the conductor properly
repaired or replaced before use.
Rationale: Damaged insulation can expose workers to shock and can
cause short circuits, arcing, ground faults, or fires. Temporary
improvised repairs should not substitute for an approved repair
method.
8. What is the primary purpose of a circuit breaker?
A. Increase circuit voltage
B. Automatically interrupt excessive current
C. Increase motor speed
D. Convert AC to DC
Answer: B. Automatically interrupt excessive current
Rationale: A circuit breaker is an overcurrent protective device. When
current exceeds its designed operating limits, the breaker opens the
circuit to help protect conductors and equipment from damage and
reduce fire hazards.
9. Which condition represents a short circuit?
4
ACTUAL QUESTIONS AND VERIFIED
ANSWERS, PLUS EXPLAINED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED 100% PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
1. A 120-volt incandescent lamp draws 2 amperes of current when
operating normally. What is the approximate resistance of the lamp
while operating?
A. 30 Ω
B. 60 Ω
C. 120 Ω
D. 240 Ω
Answer: B. 60 Ω
Rationale: Ohm’s law states that R = V ÷ I. Therefore, 120 V ÷ 2 A =
60 Ω. The resistance of an incandescent lamp changes with
temperature, so this represents its approximate operating resistance
rather than necessarily its cold resistance.
2. An electrical helper is instructed to work on a circuit that has been
de-energized. Which procedure provides the most appropriate
protection against accidental energization?
A. Turn the switch off and begin working immediately.
B. Remove the circuit's fuse and place it in a pocket.
C. Lockout/tagout the energy source and verify absence of voltage with
an appropriate tester.
D. Ask another employee whether the circuit is energized.
1
,Answer: C. Lockout/tagout the energy source and verify absence of
voltage with an appropriate tester.
Rationale: Lockout/tagout prevents unexpected energization while
work is being performed. Testing for absence of voltage is also
essential because a switch in the OFF position alone does not prove
that the conductors are electrically safe.
3. Which instrument is specifically designed to measure electrical
potential difference between two points?
A. Voltmeter
B. Ammeter
C. Ohmmeter
D. Megohmmeter only
Answer: A. Voltmeter
Rationale: A voltmeter measures voltage, or electrical potential
difference, between two points. It is normally connected in parallel
with the portion of the circuit being measured. An ammeter measures
current, while an ohmmeter measures resistance.
4. Why is an ammeter normally connected in series with a circuit
when measuring current?
A. It creates a high-resistance path that prevents current flow.
B. It allows the entire circuit current to pass through the meter.
C. It measures the voltage drop across the circuit.
D. It eliminates the need for circuit protection.
Answer: B. It allows the entire circuit current to pass through the
meter.
2
,Rationale: An ammeter is designed with very low internal resistance
and is inserted in series so the current being measured flows through
it. Connecting an ordinary ammeter directly across a voltage source
can create a near-short circuit and can damage the meter or create a
hazardous condition.
5. A circuit contains a 20-ohm load connected to a 120-volt source.
Approximately how much current flows through the load?
A. 0.17 A
B. 2 A
C. 6 A
D. 24 A
Answer: C. 6 A
Rationale: Using Ohm’s law, I = V ÷ R. Thus, 120 V ÷ 20 Ω = 6 A.
This calculation assumes the load behaves approximately as a resistive
load under the stated conditions.
6. Which electrical quantity is measured in amperes?
A. Resistance
B. Power
C. Current
D. Voltage
Answer: C. Current
Rationale: The ampere, or amp, is the SI unit of electric current.
Voltage is measured in volts, resistance in ohms, and electrical power
in watts.
3
, 7. An electrical worker finds that the insulation on a conductor has
been cut deeply enough to expose the metal conductor. What is the
safest action?
A. Wrap it with ordinary adhesive tape and continue working.
B. Bend the damaged section away from other conductors.
C. Report the damage and have the conductor properly repaired or
replaced before use.
D. Spray the conductor with insulating lubricant.
Answer: C. Report the damage and have the conductor properly
repaired or replaced before use.
Rationale: Damaged insulation can expose workers to shock and can
cause short circuits, arcing, ground faults, or fires. Temporary
improvised repairs should not substitute for an approved repair
method.
8. What is the primary purpose of a circuit breaker?
A. Increase circuit voltage
B. Automatically interrupt excessive current
C. Increase motor speed
D. Convert AC to DC
Answer: B. Automatically interrupt excessive current
Rationale: A circuit breaker is an overcurrent protective device. When
current exceeds its designed operating limits, the breaker opens the
circuit to help protect conductors and equipment from damage and
reduce fire hazards.
9. Which condition represents a short circuit?
4
