LADWP Electrical Craft Helper Exam
Questions And Correct Answers
(Verified Answers) Plus Rationales
2026 Q&A | Instant Download Pdf
1. What is the primary purpose of a circuit breaker in an electrical
circuit?
A. To increase circuit voltage
B. To provide additional resistance
C. To store electrical energy
D. To interrupt current when an unsafe condition occurs
Answer: D. To interrupt current when an unsafe condition occurs
Rationale: A circuit breaker is designed to open a circuit automatically
when current exceeds a safe value, such as during an overload or
short circuit. This interruption helps protect conductors, equipment,
and people from electrical hazards. A breaker does not increase
voltage or store energy. Its protective function is based on interrupting
excessive current before damage becomes more severe.
2. Which unit is used to measure electrical current?
A. Ampere
B. Ohm
C. Volt
D. Watt
Answer: A. Ampere
,Rationale: Electrical current is measured in amperes, commonly
abbreviated as amps or A. Voltage is measured in volts, resistance is
measured in ohms, and power is measured in watts. Understanding
these fundamental units is essential for an electrical craft helper
because electrical drawings, meters, equipment nameplates, and work
instructions frequently use them.
3. What does electrical resistance describe?
A. The amount of electrical power consumed
B. The force pushing electrons through a circuit
C. The opposition to the flow of electric current
D. The total amount of stored electrical charge
Answer: C. The opposition to the flow of electric current
Rationale: Resistance is the opposition that a material or component
presents to current flow. It is measured in ohms. According to Ohm's
law, current is related to voltage and resistance. Increasing resistance
while maintaining the same voltage generally decreases current.
Conductors such as copper have relatively low resistance, while
insulating materials have very high resistance.
4. Which instrument is commonly used to measure voltage?
A. Megohmmeter
B. Voltmeter
C. Ammeter only
D. Tachometer
Answer: B. Voltmeter
Rationale: A voltmeter measures electrical potential difference between
two points. Modern digital multimeters commonly provide voltage-
measuring functions along with resistance and current measurements.
,When measuring voltage, the worker must select the proper function
and range and use appropriately rated test leads. Incorrect meter use
can create an arc-flash or shock hazard.
5. What is the main reason an electrical worker should de-energize
equipment before performing maintenance?
A. To make the equipment operate faster
B. To reduce equipment weight
C. To improve circuit efficiency
D. To eliminate or reduce the risk of electrical shock and unexpected
energization
Answer: D. To eliminate or reduce the risk of electrical shock and
unexpected energization
Rationale: De-energizing equipment is a fundamental electrical-safety
practice. Before work begins, the circuit should be isolated from its
energy source and appropriate lockout/tagout procedures followed.
Simply switching a device off is not necessarily sufficient because
another source, stored energy, or inadvertent re-energization may still
exist.
6. Which color is commonly associated with the equipment
grounding conductor in typical wiring systems?
A. Green or bare
B. Orange only
C. Blue only
D. White only
Answer: A. Green or bare
Rationale: Equipment grounding conductors are commonly identified
by green insulation or by being bare. Their purpose is to provide a low-
, impedance path for fault current so protective devices can operate.
White or gray conductors are generally associated with grounded
conductors, while ungrounded conductors are typically identified by
other colors. Always follow the applicable electrical code and site
requirements.
7. What does Ohm's law express?
A. Power equals current divided by voltage
B. Resistance equals power multiplied by current
C. Voltage equals current multiplied by resistance
D. Current equals voltage multiplied by resistance
Answer: C. Voltage equals current multiplied by resistance
Rationale: Ohm's law is expressed as V = I × R, where V is voltage, I is
current, and R is resistance. The relationship can also be rearranged
to find current or resistance. This basic formula is frequently used
when analyzing simple electrical circuits and understanding how
changes in resistance or voltage affect current.
8. Which tool is most appropriate for tightening a screw terminal to a
specified torque?
A. Pipe wrench
B. Torque screwdriver or torque wrench
C. Cold chisel
D. Slip-joint pliers
Answer: B. Torque screwdriver or torque wrench
Rationale: Electrical terminals often require a manufacturer-specified
tightening torque. A torque screwdriver or torque wrench allows the
worker to achieve the required value accurately. Under-tightening can
cause high-resistance connections and overheating, while over-
Questions And Correct Answers
(Verified Answers) Plus Rationales
2026 Q&A | Instant Download Pdf
1. What is the primary purpose of a circuit breaker in an electrical
circuit?
A. To increase circuit voltage
B. To provide additional resistance
C. To store electrical energy
D. To interrupt current when an unsafe condition occurs
Answer: D. To interrupt current when an unsafe condition occurs
Rationale: A circuit breaker is designed to open a circuit automatically
when current exceeds a safe value, such as during an overload or
short circuit. This interruption helps protect conductors, equipment,
and people from electrical hazards. A breaker does not increase
voltage or store energy. Its protective function is based on interrupting
excessive current before damage becomes more severe.
2. Which unit is used to measure electrical current?
A. Ampere
B. Ohm
C. Volt
D. Watt
Answer: A. Ampere
,Rationale: Electrical current is measured in amperes, commonly
abbreviated as amps or A. Voltage is measured in volts, resistance is
measured in ohms, and power is measured in watts. Understanding
these fundamental units is essential for an electrical craft helper
because electrical drawings, meters, equipment nameplates, and work
instructions frequently use them.
3. What does electrical resistance describe?
A. The amount of electrical power consumed
B. The force pushing electrons through a circuit
C. The opposition to the flow of electric current
D. The total amount of stored electrical charge
Answer: C. The opposition to the flow of electric current
Rationale: Resistance is the opposition that a material or component
presents to current flow. It is measured in ohms. According to Ohm's
law, current is related to voltage and resistance. Increasing resistance
while maintaining the same voltage generally decreases current.
Conductors such as copper have relatively low resistance, while
insulating materials have very high resistance.
4. Which instrument is commonly used to measure voltage?
A. Megohmmeter
B. Voltmeter
C. Ammeter only
D. Tachometer
Answer: B. Voltmeter
Rationale: A voltmeter measures electrical potential difference between
two points. Modern digital multimeters commonly provide voltage-
measuring functions along with resistance and current measurements.
,When measuring voltage, the worker must select the proper function
and range and use appropriately rated test leads. Incorrect meter use
can create an arc-flash or shock hazard.
5. What is the main reason an electrical worker should de-energize
equipment before performing maintenance?
A. To make the equipment operate faster
B. To reduce equipment weight
C. To improve circuit efficiency
D. To eliminate or reduce the risk of electrical shock and unexpected
energization
Answer: D. To eliminate or reduce the risk of electrical shock and
unexpected energization
Rationale: De-energizing equipment is a fundamental electrical-safety
practice. Before work begins, the circuit should be isolated from its
energy source and appropriate lockout/tagout procedures followed.
Simply switching a device off is not necessarily sufficient because
another source, stored energy, or inadvertent re-energization may still
exist.
6. Which color is commonly associated with the equipment
grounding conductor in typical wiring systems?
A. Green or bare
B. Orange only
C. Blue only
D. White only
Answer: A. Green or bare
Rationale: Equipment grounding conductors are commonly identified
by green insulation or by being bare. Their purpose is to provide a low-
, impedance path for fault current so protective devices can operate.
White or gray conductors are generally associated with grounded
conductors, while ungrounded conductors are typically identified by
other colors. Always follow the applicable electrical code and site
requirements.
7. What does Ohm's law express?
A. Power equals current divided by voltage
B. Resistance equals power multiplied by current
C. Voltage equals current multiplied by resistance
D. Current equals voltage multiplied by resistance
Answer: C. Voltage equals current multiplied by resistance
Rationale: Ohm's law is expressed as V = I × R, where V is voltage, I is
current, and R is resistance. The relationship can also be rearranged
to find current or resistance. This basic formula is frequently used
when analyzing simple electrical circuits and understanding how
changes in resistance or voltage affect current.
8. Which tool is most appropriate for tightening a screw terminal to a
specified torque?
A. Pipe wrench
B. Torque screwdriver or torque wrench
C. Cold chisel
D. Slip-joint pliers
Answer: B. Torque screwdriver or torque wrench
Rationale: Electrical terminals often require a manufacturer-specified
tightening torque. A torque screwdriver or torque wrench allows the
worker to achieve the required value accurately. Under-tightening can
cause high-resistance connections and overheating, while over-
