LADWP Electric Station Operator (Circuit
Breakers, Disconnects,Transformers) (Latest
2026/2027 Update) 100% Verified Actual Exam
Questions & Answers | Grade A
This LADWP Electric Station Operator Practice Exam is a targeted, 100+ question
study guide designed to help candidates pass the rigorous Los Angeles Department of Water
and Power (LADWP) selection process. It focuses on high-voltage substation operations, circuit
breaker control, transformer management, and electrical switching safety.
Key Features for Exam Prep
• 100+ Verified Q&As: Covers real-world exam topics with accurate Answers
• Substation Focus: Tests core knowledge of circuit breakers, disconnects, and
transformer operations.
• Safety & Switching: Emphasizes high-voltage safety protocols, switching sequences,
and visual isolation procedures.
• Career Ready: Aligns with the knowledge required for the LADWP Electric Station
Operator (Code 5224) role.
Q1. Which devices are not designed to interrupt current flow or to open and
close circuits under load? [Multiple Choice]
A) Automatic reclosers
B) Transformers
C) Circuit breakers
D) Disconnects
Answer: Disconnects
Explanation: Disconnects are intended for visible isolation of circuits and short conductor
sections but are not rated to interrupt load currents or be used to open/close live circuits. Circuit
breakers and automatic reclosers are specifically designed to interrupt load current; transformers
are power equipment and not safety isolation devices but are not the answer here.
1
,Q2. What kind of operation of electrical switches can pose a serious hazard to
personnel and cause destruction of equipment and service interruption? [Multiple
Choice]
A) routine
B) automatic
C) emergency
D) improper
Answer: improper
Explanation: Improper operation—meaning incorrect or unsafe use—can create hazards,
damage equipment, or interrupt service because it may leave circuits energized or create arcs.
Routine, automatic, and emergency are types of switching operations described in the text; while
they carry risks if done poorly, the specific danger called out is from improper operation, not from
those named categories themselves.
Q3. During abnormal conditions, current often exceeds the normal limitation of
these devices by about how many times their normal rating? [Multiple Choice]
A) 50 to 100 times
B) 10 to 20 times
C) 0.2 seconds
D) 120 times per second
Answer: 10 to 20 times
Explanation: The text notes that during abnormal conditions currents can reach roughly 10 to 20
times a device's normal rating, which explains why interrupting devices must be robust. '50 to
100' refers elsewhere to the number of switch contacts current may cross, not a multiplier of
device ratings; '0.2 seconds' describes a breaker operating time, not a current multiple; '120
times per second' describes AC zero crossings in a 60 Hz system, not an overcurrent multiplier.
Q4. Electrical current may flow across the contacts of approximately how many
electrical switches before reaching the consumer? [Multiple Choice]
A) 0.2 seconds
B) 50 to 100
C) 10 to 20
D) 120 times per second
2
, Answer: 50 to 100
Explanation: The text states that current can cross many switch contacts on its path to the
consumer; the cited range is 50 to 100 contacts. '10 to 20' is mentioned elsewhere in the text as a
multiple of normal ratings during abnormal conditions, not as the number of switches; '0.2
seconds' refers to operating time of some breakers, not a count of switches; '120 times per
second' describes how often AC crosses zero in a 60 Hz system, not how many switches the
current crosses.
Q5. Operators use electrical switches to perform routine and automatic
switching and which other type of switching? [Multiple Choice]
A) maintenance
B) emergency
C) construction
D) testing
Answer: emergency
Explanation: The text lists three broad categories of switching performed by operators: routine,
automatic, and emergency. Maintenance, construction, and testing are examples of routine
switching activities, so they are not the third main category; the correct category that stands
alongside routine and automatic is emergency switching.
Q6. Explain how the dielectric medium between open circuit-breaker contacts
prevents current from flowing when the breaker is open and why its dielectric
strength matters. [Short Answer]
Answer: The dielectric medium occupies the space between the open contacts and,
because it has dielectric strength, it resists the passage of electrical current so the circuit
remains interrupted while the contacts are open. If the voltage across the contacts stays
below the medium’s dielectric strength, no current will flow.
Explanation: A complete answer identifies the dielectric medium as the insulating mechanism
that fills the gap between open contacts and explains the role of dielectric strength: it is the
substance’s ability to prevent current flow. The learner should show that as long as the applied
voltage does not exceed that strength, the medium prevents conduction and the breaker
successfully interrupts the circuit.
Q7. Why is alternating current (AC) easier to interrupt than direct current (DC)
according to the text? [Multiple Choice]
A) Because the current value becomes very high
3
, B) Because the current value becomes negative
C) Because the current value periodically becomes zero
D) Because the current value remains steady
Answer: Because the current value periodically becomes zero
Explanation: AC alternates and crosses zero periodically (for example 120 times per second in a
60 Hz system). When the current reaches zero, an arc is easier to extinguish and interruption is
simpler. Saying the current becomes negative is true for half the cycle but that does not aid
interruption; becoming very high would make interruption harder, not easier; remaining steady is
a characteristic of DC and makes interruption more difficult because there is no natural zero-
crossing.
Q8. Which electrical switches are used to manipulate relatively high values of
current and voltage in circuits that are carrying current or will carry current
following the operation? [Multiple Choice]
A) Circuit breakers
B) Control circuits
C) Transformers
D) Disconnects
Answer: Circuit breakers
Explanation: Circuit breakers are specifically designed to handle large currents and voltages and
to interrupt or make circuits that are carrying current. Disconnects are intended for visual
isolation of sections and not for interrupting heavy load currents; transformers change voltage
levels but are not switching devices for interrupting load current; control circuits are auxiliary
systems that direct breaker action, not devices that themselves manipulate high power currents.
Q9. What devices are provided as a method of visually confirming that a circuit
has been disconnected from specified sources of electrical energy? [Multiple Choice]
A) Disconnects
B) Transformers
C) Semaphores
D) Circuit breakers
Answer: Disconnects
4
Breakers, Disconnects,Transformers) (Latest
2026/2027 Update) 100% Verified Actual Exam
Questions & Answers | Grade A
This LADWP Electric Station Operator Practice Exam is a targeted, 100+ question
study guide designed to help candidates pass the rigorous Los Angeles Department of Water
and Power (LADWP) selection process. It focuses on high-voltage substation operations, circuit
breaker control, transformer management, and electrical switching safety.
Key Features for Exam Prep
• 100+ Verified Q&As: Covers real-world exam topics with accurate Answers
• Substation Focus: Tests core knowledge of circuit breakers, disconnects, and
transformer operations.
• Safety & Switching: Emphasizes high-voltage safety protocols, switching sequences,
and visual isolation procedures.
• Career Ready: Aligns with the knowledge required for the LADWP Electric Station
Operator (Code 5224) role.
Q1. Which devices are not designed to interrupt current flow or to open and
close circuits under load? [Multiple Choice]
A) Automatic reclosers
B) Transformers
C) Circuit breakers
D) Disconnects
Answer: Disconnects
Explanation: Disconnects are intended for visible isolation of circuits and short conductor
sections but are not rated to interrupt load currents or be used to open/close live circuits. Circuit
breakers and automatic reclosers are specifically designed to interrupt load current; transformers
are power equipment and not safety isolation devices but are not the answer here.
1
,Q2. What kind of operation of electrical switches can pose a serious hazard to
personnel and cause destruction of equipment and service interruption? [Multiple
Choice]
A) routine
B) automatic
C) emergency
D) improper
Answer: improper
Explanation: Improper operation—meaning incorrect or unsafe use—can create hazards,
damage equipment, or interrupt service because it may leave circuits energized or create arcs.
Routine, automatic, and emergency are types of switching operations described in the text; while
they carry risks if done poorly, the specific danger called out is from improper operation, not from
those named categories themselves.
Q3. During abnormal conditions, current often exceeds the normal limitation of
these devices by about how many times their normal rating? [Multiple Choice]
A) 50 to 100 times
B) 10 to 20 times
C) 0.2 seconds
D) 120 times per second
Answer: 10 to 20 times
Explanation: The text notes that during abnormal conditions currents can reach roughly 10 to 20
times a device's normal rating, which explains why interrupting devices must be robust. '50 to
100' refers elsewhere to the number of switch contacts current may cross, not a multiplier of
device ratings; '0.2 seconds' describes a breaker operating time, not a current multiple; '120
times per second' describes AC zero crossings in a 60 Hz system, not an overcurrent multiplier.
Q4. Electrical current may flow across the contacts of approximately how many
electrical switches before reaching the consumer? [Multiple Choice]
A) 0.2 seconds
B) 50 to 100
C) 10 to 20
D) 120 times per second
2
, Answer: 50 to 100
Explanation: The text states that current can cross many switch contacts on its path to the
consumer; the cited range is 50 to 100 contacts. '10 to 20' is mentioned elsewhere in the text as a
multiple of normal ratings during abnormal conditions, not as the number of switches; '0.2
seconds' refers to operating time of some breakers, not a count of switches; '120 times per
second' describes how often AC crosses zero in a 60 Hz system, not how many switches the
current crosses.
Q5. Operators use electrical switches to perform routine and automatic
switching and which other type of switching? [Multiple Choice]
A) maintenance
B) emergency
C) construction
D) testing
Answer: emergency
Explanation: The text lists three broad categories of switching performed by operators: routine,
automatic, and emergency. Maintenance, construction, and testing are examples of routine
switching activities, so they are not the third main category; the correct category that stands
alongside routine and automatic is emergency switching.
Q6. Explain how the dielectric medium between open circuit-breaker contacts
prevents current from flowing when the breaker is open and why its dielectric
strength matters. [Short Answer]
Answer: The dielectric medium occupies the space between the open contacts and,
because it has dielectric strength, it resists the passage of electrical current so the circuit
remains interrupted while the contacts are open. If the voltage across the contacts stays
below the medium’s dielectric strength, no current will flow.
Explanation: A complete answer identifies the dielectric medium as the insulating mechanism
that fills the gap between open contacts and explains the role of dielectric strength: it is the
substance’s ability to prevent current flow. The learner should show that as long as the applied
voltage does not exceed that strength, the medium prevents conduction and the breaker
successfully interrupts the circuit.
Q7. Why is alternating current (AC) easier to interrupt than direct current (DC)
according to the text? [Multiple Choice]
A) Because the current value becomes very high
3
, B) Because the current value becomes negative
C) Because the current value periodically becomes zero
D) Because the current value remains steady
Answer: Because the current value periodically becomes zero
Explanation: AC alternates and crosses zero periodically (for example 120 times per second in a
60 Hz system). When the current reaches zero, an arc is easier to extinguish and interruption is
simpler. Saying the current becomes negative is true for half the cycle but that does not aid
interruption; becoming very high would make interruption harder, not easier; remaining steady is
a characteristic of DC and makes interruption more difficult because there is no natural zero-
crossing.
Q8. Which electrical switches are used to manipulate relatively high values of
current and voltage in circuits that are carrying current or will carry current
following the operation? [Multiple Choice]
A) Circuit breakers
B) Control circuits
C) Transformers
D) Disconnects
Answer: Circuit breakers
Explanation: Circuit breakers are specifically designed to handle large currents and voltages and
to interrupt or make circuits that are carrying current. Disconnects are intended for visual
isolation of sections and not for interrupting heavy load currents; transformers change voltage
levels but are not switching devices for interrupting load current; control circuits are auxiliary
systems that direct breaker action, not devices that themselves manipulate high power currents.
Q9. What devices are provided as a method of visually confirming that a circuit
has been disconnected from specified sources of electrical energy? [Multiple Choice]
A) Disconnects
B) Transformers
C) Semaphores
D) Circuit breakers
Answer: Disconnects
4
