LADWP ELECTRIC STATION OPERATOR
(CIRCUIT BREAKERS, DISCONNECTS,
TRANSFORMERS) EXAM WITH ACTUAL
CORRECT QUESTIONS AND VERIFIED
DETAILED ANSWERS| CURRENTLY TESTING
VERSION | ALREADY GRADED A+|EXPERT
VERIFIED FOR GUARANTEED PASS 2026
Severe contamination of a dielectric medium can cause CBs to __________ by allowing an
arc to be sustained between the open contacts or the contacts and the grounded tank(s) or
housing of the CB.
explode
__________ are usually made of insulating porcelain.
Bushings
Portions of the mechanical linkages connected to movable contacts must be constructed of
__________ materials to prevent the electrical components of the contacts and conductors
from energizing the components of the CB such as the tank, controls, etc.
Nonconductive
The operating time, from fully open to fully closed, in many large CBs, is often less than
__________ seconds.
0.2
Failure of the mechanical __________ (sometimes referred to as the actuating arm or lever)
can cause serious damage to the circuit breaker or may cause normally non-energized
portions of the CB to become energized.
linkage
__________ circuits use auxiliary devices that direct the operation of the CB.
1|Page
, Control
The mechanical indicator used at the CB to indicate the status of the breaker is called the
___________.
Semaphore
__________ must never be used to interrupt current flow in circuit.
Disconnects
__________ are usually operated manually by the use of levers, cranks, and "hook-sticks
poles."
Disconnects
The size of an electric arc and destruction it can cause are directly proportional to the
amount of ___________ being interrupted.
current
The current that continues to flow across the opening contacts of a switch (or across any
opening in a circuit) is known as an __________.
Arc
Dry, clean air normally has a __________ strength of about 10,000 volts per inch. This
means that you would have to apply a voltage greater than 10,000 volts across conductors
separated by one inch of air to establish current flow across the separated conductors.
dielectric
Air has a high __________ value so this current flow creates heat.
resistance
Using multiple contacts and rapid opening times helps __________ the arc by reducing the
cross sectional area of the arc or by lengthening it.
cool
2|Page
(CIRCUIT BREAKERS, DISCONNECTS,
TRANSFORMERS) EXAM WITH ACTUAL
CORRECT QUESTIONS AND VERIFIED
DETAILED ANSWERS| CURRENTLY TESTING
VERSION | ALREADY GRADED A+|EXPERT
VERIFIED FOR GUARANTEED PASS 2026
Severe contamination of a dielectric medium can cause CBs to __________ by allowing an
arc to be sustained between the open contacts or the contacts and the grounded tank(s) or
housing of the CB.
explode
__________ are usually made of insulating porcelain.
Bushings
Portions of the mechanical linkages connected to movable contacts must be constructed of
__________ materials to prevent the electrical components of the contacts and conductors
from energizing the components of the CB such as the tank, controls, etc.
Nonconductive
The operating time, from fully open to fully closed, in many large CBs, is often less than
__________ seconds.
0.2
Failure of the mechanical __________ (sometimes referred to as the actuating arm or lever)
can cause serious damage to the circuit breaker or may cause normally non-energized
portions of the CB to become energized.
linkage
__________ circuits use auxiliary devices that direct the operation of the CB.
1|Page
, Control
The mechanical indicator used at the CB to indicate the status of the breaker is called the
___________.
Semaphore
__________ must never be used to interrupt current flow in circuit.
Disconnects
__________ are usually operated manually by the use of levers, cranks, and "hook-sticks
poles."
Disconnects
The size of an electric arc and destruction it can cause are directly proportional to the
amount of ___________ being interrupted.
current
The current that continues to flow across the opening contacts of a switch (or across any
opening in a circuit) is known as an __________.
Arc
Dry, clean air normally has a __________ strength of about 10,000 volts per inch. This
means that you would have to apply a voltage greater than 10,000 volts across conductors
separated by one inch of air to establish current flow across the separated conductors.
dielectric
Air has a high __________ value so this current flow creates heat.
resistance
Using multiple contacts and rapid opening times helps __________ the arc by reducing the
cross sectional area of the arc or by lengthening it.
cool
2|Page
