LADWP ELECTRICAL MECHANIC AND
TEST TECHNICIAN EXAM 2026 THE
ULTIMATE STUDY GUIDE AND 200 PLUS
VERIFIED PRACTICE QUESTIONS
LADWP Electrical Mechanic–Test Technician Practice
1. A technician is measuring the insulation resistance of a
high-voltage transformer using a megohmmeter. Which of the
following conditions would most likely result in a lower-than-
normal resistance reading?
A. The conductor temperature is significantly below 20°C.
B. The transformer bushings have just been cleaned with an approved
solvent.
C. There is a high level of moisture or surface contamination
on the windings.
D. The test leads are properly shielded and separated from the ground.
Rationale: Moisture and surface contaminants create conductive paths
that allow current leakage, thereby decreasing the measured insulation
resistance (Megohms).
2. When calculating the total power dissipated in a parallel
circuit containing three resistors of varying values, which
statement accurately describes the relationship between
individual power and total power?
A. Total power is equal to the average power of the three individual
resistors.
B. Total power is determined solely by the resistor with the lowest
resistance.
C. Total power is the sum of the power dissipated by each
individual resistor regardless of the circuit configuration.
D. Total power is found by multiplying the total current by the value of
the largest resistor.
Rationale: According to the Law of Conservation of Energy, the total
power consumed in any DC circuit (series or parallel) is always the sum
of the individual power values.
,3. During a routine maintenance check, a Test Technician
identifies a "hot spot" on a busbar connection using an
infrared thermography camera. What is the most likely cause
of this thermal anomaly?
A. The circuit is operating at exactly 80% of its rated capacity.
B. The busbar material has a high thermal conductivity rating.
C. Increased contact resistance due to a loose bolt or oxidation
at the joint.
D. The cooling fans in the substation are rotating in the correct direction.
Rationale: High resistance at a connection point (caused by looseness
or corrosion) creates localized heat when current flows (
), leading to thermal failure if not addressed.
4. A step-down transformer has a primary-to-secondary turns
ratio of 10:1. If the primary voltage is 4,800V and the
secondary load pulls 200A, what is the approximate current
flowing through the primary winding, assuming an ideal
transformer?
A. 20 Amps
B. 2,000 Amps
C. 480 Amps
D. 200 Amps
Rationale: In an ideal transformer, the current ratio is the inverse of
the voltage/turns ratio (
). If voltage drops by a factor of 10, current increases by a factor of 10
on the secondary; therefore, the primary current is
,.
5. According to standard LADWP safety protocols, what is the
primary purpose of applying a "Personal Ground" after a line
has been de-energized and tested for dead?
A. To prevent the equipment from being energized by the utility's
automated SCADA system.
B. To provide a path for the normal operating current to return to the
substation.
C. To protect the worker from accidental re-energization or
induced voltage from adjacent lines.
D. To ensure that the multimeter displays a zero-voltage reading during
the final check.
Rationale: Personal grounds create a low-impedance path to earth,
ensuring that if a line becomes accidentally "hot," the current is
diverted away from the worker and triggers protective relaying.
8. Which of the following electrical components is specifically
designed to store energy in a magnetic field when current
flows through it?
A. Resistor
B. Capacitor
C. Inductor
D. Diode
Rationale: An inductor (or coil) opposes changes in current by storing
energy in a magnetic field, whereas a capacitor stores energy in an
electric field.
9. When using a Megger to test a 480V motor, a reading of 0.5
Megohms is obtained. Based on general industry "rule of
thumb" standards, how should this motor be categorized?
A. The insulation is likely degraded or wet and requires
investigation before service.
B. The insulation is in excellent condition for a 480V system.
C. The motor is perfectly safe as long as the frame is grounded.
D. The reading indicates a direct short to ground.
Rationale: A standard baseline is 1 Megohm per kV of operating
voltage plus 1. A reading of 0.5 Megohms is below the safe threshold for
480V equipment.
10. What happens to the total resistance in a DC parallel
circuit if an additional resistor is added in parallel to the
, existing branches?
A. The total resistance increases.
B. The total resistance decreases.
C. The total resistance remains the same.
D. The total resistance becomes the average of all resistors.
Rationale: Adding parallel paths provides more avenues for current to
flow, which mathematically reduces the equivalent total resistance of
the circuit.
11. A technician needs to measure the current in a conductor
without breaking the circuit. Which tool is most appropriate
for this task?
A. Ohmmeter
B. Galvanometer
C. Clamp-on Ammeter
D. Wheatstone Bridge
Rationale: A clamp-on ammeter uses the principle of electromagnetic
induction to sense the magnetic field around a wire and convert it to a
current reading.
12. Which statement best describes the function of a "Shunt"
used in conjunction with a DC ammeter?
A. It provides a low-resistance path to bypass the majority of
the current around the meter movement.
B. It increases the voltage drop across the meter to improve sensitivity.
C. It acts as a fuse to protect the meter from overvoltage.
D. It converts AC current into DC current for the meter to read.
Rationale: Ammeter movements are delicate; a shunt allows the bulk of
high current to pass through a calibrated resistor while the meter
measures a small, proportional fraction.
13. In a series RL circuit, the voltage across the resistor is 30V
and the voltage across the inductor is 40V. What is the total
source voltage?
A. 70V
B. 10V
C. 50V
D. 1,200V
Rationale: In AC circuits, voltages are added vectorially.
TEST TECHNICIAN EXAM 2026 THE
ULTIMATE STUDY GUIDE AND 200 PLUS
VERIFIED PRACTICE QUESTIONS
LADWP Electrical Mechanic–Test Technician Practice
1. A technician is measuring the insulation resistance of a
high-voltage transformer using a megohmmeter. Which of the
following conditions would most likely result in a lower-than-
normal resistance reading?
A. The conductor temperature is significantly below 20°C.
B. The transformer bushings have just been cleaned with an approved
solvent.
C. There is a high level of moisture or surface contamination
on the windings.
D. The test leads are properly shielded and separated from the ground.
Rationale: Moisture and surface contaminants create conductive paths
that allow current leakage, thereby decreasing the measured insulation
resistance (Megohms).
2. When calculating the total power dissipated in a parallel
circuit containing three resistors of varying values, which
statement accurately describes the relationship between
individual power and total power?
A. Total power is equal to the average power of the three individual
resistors.
B. Total power is determined solely by the resistor with the lowest
resistance.
C. Total power is the sum of the power dissipated by each
individual resistor regardless of the circuit configuration.
D. Total power is found by multiplying the total current by the value of
the largest resistor.
Rationale: According to the Law of Conservation of Energy, the total
power consumed in any DC circuit (series or parallel) is always the sum
of the individual power values.
,3. During a routine maintenance check, a Test Technician
identifies a "hot spot" on a busbar connection using an
infrared thermography camera. What is the most likely cause
of this thermal anomaly?
A. The circuit is operating at exactly 80% of its rated capacity.
B. The busbar material has a high thermal conductivity rating.
C. Increased contact resistance due to a loose bolt or oxidation
at the joint.
D. The cooling fans in the substation are rotating in the correct direction.
Rationale: High resistance at a connection point (caused by looseness
or corrosion) creates localized heat when current flows (
), leading to thermal failure if not addressed.
4. A step-down transformer has a primary-to-secondary turns
ratio of 10:1. If the primary voltage is 4,800V and the
secondary load pulls 200A, what is the approximate current
flowing through the primary winding, assuming an ideal
transformer?
A. 20 Amps
B. 2,000 Amps
C. 480 Amps
D. 200 Amps
Rationale: In an ideal transformer, the current ratio is the inverse of
the voltage/turns ratio (
). If voltage drops by a factor of 10, current increases by a factor of 10
on the secondary; therefore, the primary current is
,.
5. According to standard LADWP safety protocols, what is the
primary purpose of applying a "Personal Ground" after a line
has been de-energized and tested for dead?
A. To prevent the equipment from being energized by the utility's
automated SCADA system.
B. To provide a path for the normal operating current to return to the
substation.
C. To protect the worker from accidental re-energization or
induced voltage from adjacent lines.
D. To ensure that the multimeter displays a zero-voltage reading during
the final check.
Rationale: Personal grounds create a low-impedance path to earth,
ensuring that if a line becomes accidentally "hot," the current is
diverted away from the worker and triggers protective relaying.
8. Which of the following electrical components is specifically
designed to store energy in a magnetic field when current
flows through it?
A. Resistor
B. Capacitor
C. Inductor
D. Diode
Rationale: An inductor (or coil) opposes changes in current by storing
energy in a magnetic field, whereas a capacitor stores energy in an
electric field.
9. When using a Megger to test a 480V motor, a reading of 0.5
Megohms is obtained. Based on general industry "rule of
thumb" standards, how should this motor be categorized?
A. The insulation is likely degraded or wet and requires
investigation before service.
B. The insulation is in excellent condition for a 480V system.
C. The motor is perfectly safe as long as the frame is grounded.
D. The reading indicates a direct short to ground.
Rationale: A standard baseline is 1 Megohm per kV of operating
voltage plus 1. A reading of 0.5 Megohms is below the safe threshold for
480V equipment.
10. What happens to the total resistance in a DC parallel
circuit if an additional resistor is added in parallel to the
, existing branches?
A. The total resistance increases.
B. The total resistance decreases.
C. The total resistance remains the same.
D. The total resistance becomes the average of all resistors.
Rationale: Adding parallel paths provides more avenues for current to
flow, which mathematically reduces the equivalent total resistance of
the circuit.
11. A technician needs to measure the current in a conductor
without breaking the circuit. Which tool is most appropriate
for this task?
A. Ohmmeter
B. Galvanometer
C. Clamp-on Ammeter
D. Wheatstone Bridge
Rationale: A clamp-on ammeter uses the principle of electromagnetic
induction to sense the magnetic field around a wire and convert it to a
current reading.
12. Which statement best describes the function of a "Shunt"
used in conjunction with a DC ammeter?
A. It provides a low-resistance path to bypass the majority of
the current around the meter movement.
B. It increases the voltage drop across the meter to improve sensitivity.
C. It acts as a fuse to protect the meter from overvoltage.
D. It converts AC current into DC current for the meter to read.
Rationale: Ammeter movements are delicate; a shunt allows the bulk of
high current to pass through a calibrated resistor while the meter
measures a small, proportional fraction.
13. In a series RL circuit, the voltage across the resistor is 30V
and the voltage across the inductor is 40V. What is the total
source voltage?
A. 70V
B. 10V
C. 50V
D. 1,200V
Rationale: In AC circuits, voltages are added vectorially.
