LADWP STREET LIGHTING ELECTRICIAN
EXAM WITH ACTUAL QUESTIONS AND
VERIFIED ANSWERS, PLUS EXPLAINED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED 100% PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
1. A street-lighting electrician is troubleshooting a section of
multiple-circuit street lighting in which several luminaires are
completely dark, while luminaires on another circuit remain
illuminated. What should be the electrician's FIRST diagnostic
priority?
A. Replace every lamp in the affected section
B. Determine whether the affected circuit has lost its source, protective
device, or continuity
C. Replace all photocells on the poles
D. Increase the circuit voltage to compensate for the outage
Answer: B. Determine whether the affected circuit has lost its
source, protective device, or continuity
Rationale: A complete outage affecting multiple luminaires on one
circuit strongly suggests a common upstream problem rather than
simultaneous individual lamp failures. The electrician should
systematically determine whether the supply, overcurrent protection,
switching equipment, conductors, connections, or circuit continuity is
responsible. Increasing voltage or replacing components without
diagnosis is unsafe and can create additional failures.
1
,2. A 120-volt luminaire draws 5 amperes under normal operating
conditions. Assuming an ideal power factor of 1.0, approximately
how much real power does the luminaire consume?
A. 24 W
B. 125 W
C. 600 W
D. 1,200 W
Answer: C. 600 W
Rationale: Electrical power in a simple single-phase resistive
approximation is P = V × I. Therefore, 120 V × 5 A = 600 W.
Understanding the relationship among voltage, current, resistance,
and power is fundamental when diagnosing street-lighting loads and
circuit capacity.
3. During inspection of an underground street-lighting circuit, an
electrician finds a conductor with damaged insulation exposing
copper. What is the most appropriate response?
A. Wrap the exposed section with ordinary household tape and energize
it
B. Ignore it if the conductor still carries current
C. Repair or replace the conductor using an approved method and verify
the circuit before energization
D. Increase the overcurrent protection so the conductor will not trip
Answer: C. Repair or replace the conductor using an approved
method and verify the circuit before energization
Rationale: Damaged insulation can permit leakage, short circuits,
faults, or shock hazards. An approved repair or replacement method
must restore the conductor's electrical and mechanical integrity.
Household tape is not an acceptable substitute for an engineered
2
,electrical repair, and increasing overcurrent protection can make a
dangerous condition substantially worse.
4. Why is a photocontrol commonly used in an automatic street-
lighting system?
A. To increase conductor ampacity
B. To automatically control lighting based on ambient light conditions
C. To convert AC into DC
D. To eliminate the need for overcurrent protection
Answer: B. To automatically control lighting based on ambient light
conditions
Rationale: A photocontrol senses ambient illumination and operates a
switching mechanism so street lights can turn on when it becomes
sufficiently dark and turn off when adequate daylight returns. It does
not increase conductor capacity, convert AC to DC, or replace
required protective devices.
5. An electrician measures continuity through a conductor that is
disconnected from all sources, but the conductor has not yet been
tested for insulation resistance to ground. What conclusion is
justified?
A. The conductor is automatically safe to energize
B. The conductor definitely has no insulation defects
C. The conductor has continuity, but additional testing may be necessary
D. The circuit is guaranteed to have the correct polarity
Answer: C. The conductor has continuity, but additional testing
may be necessary
3
, Rationale: A continuity test establishes that an electrical path exists
between the test points. It does not necessarily establish that insulation
is intact, that the conductor is correctly identified, that polarity is
correct, or that there is no leakage to ground. Diagnostic testing must
match the suspected failure mode.
6. A 20-ohm load is connected across a 120-volt source.
Approximately how much current flows through the load?
A. 0.167 A
B. 6 A
C. 20 A
D. 140 A
Answer: B. 6 A
Rationale: Ohm's law gives I = V/R. Thus I = 120/20 = 6 amperes.
Being able to perform this calculation quickly helps an electrician
estimate expected current and recognize measurements that are
inconsistent with normal circuit operation.
7. A series circuit contains three lamps. If one lamp becomes an
open circuit, what generally happens to the current through the
series path?
A. It increases substantially
B. It remains exactly the same
C. It becomes zero through the open series path
D. It reverses direction
Answer: C. It becomes zero through the open series path
Rationale: A series circuit has a single current path. An open circuit at
any point interrupts that path and prevents current from flowing
4
EXAM WITH ACTUAL QUESTIONS AND
VERIFIED ANSWERS, PLUS EXPLAINED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED 100% PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
1. A street-lighting electrician is troubleshooting a section of
multiple-circuit street lighting in which several luminaires are
completely dark, while luminaires on another circuit remain
illuminated. What should be the electrician's FIRST diagnostic
priority?
A. Replace every lamp in the affected section
B. Determine whether the affected circuit has lost its source, protective
device, or continuity
C. Replace all photocells on the poles
D. Increase the circuit voltage to compensate for the outage
Answer: B. Determine whether the affected circuit has lost its
source, protective device, or continuity
Rationale: A complete outage affecting multiple luminaires on one
circuit strongly suggests a common upstream problem rather than
simultaneous individual lamp failures. The electrician should
systematically determine whether the supply, overcurrent protection,
switching equipment, conductors, connections, or circuit continuity is
responsible. Increasing voltage or replacing components without
diagnosis is unsafe and can create additional failures.
1
,2. A 120-volt luminaire draws 5 amperes under normal operating
conditions. Assuming an ideal power factor of 1.0, approximately
how much real power does the luminaire consume?
A. 24 W
B. 125 W
C. 600 W
D. 1,200 W
Answer: C. 600 W
Rationale: Electrical power in a simple single-phase resistive
approximation is P = V × I. Therefore, 120 V × 5 A = 600 W.
Understanding the relationship among voltage, current, resistance,
and power is fundamental when diagnosing street-lighting loads and
circuit capacity.
3. During inspection of an underground street-lighting circuit, an
electrician finds a conductor with damaged insulation exposing
copper. What is the most appropriate response?
A. Wrap the exposed section with ordinary household tape and energize
it
B. Ignore it if the conductor still carries current
C. Repair or replace the conductor using an approved method and verify
the circuit before energization
D. Increase the overcurrent protection so the conductor will not trip
Answer: C. Repair or replace the conductor using an approved
method and verify the circuit before energization
Rationale: Damaged insulation can permit leakage, short circuits,
faults, or shock hazards. An approved repair or replacement method
must restore the conductor's electrical and mechanical integrity.
Household tape is not an acceptable substitute for an engineered
2
,electrical repair, and increasing overcurrent protection can make a
dangerous condition substantially worse.
4. Why is a photocontrol commonly used in an automatic street-
lighting system?
A. To increase conductor ampacity
B. To automatically control lighting based on ambient light conditions
C. To convert AC into DC
D. To eliminate the need for overcurrent protection
Answer: B. To automatically control lighting based on ambient light
conditions
Rationale: A photocontrol senses ambient illumination and operates a
switching mechanism so street lights can turn on when it becomes
sufficiently dark and turn off when adequate daylight returns. It does
not increase conductor capacity, convert AC to DC, or replace
required protective devices.
5. An electrician measures continuity through a conductor that is
disconnected from all sources, but the conductor has not yet been
tested for insulation resistance to ground. What conclusion is
justified?
A. The conductor is automatically safe to energize
B. The conductor definitely has no insulation defects
C. The conductor has continuity, but additional testing may be necessary
D. The circuit is guaranteed to have the correct polarity
Answer: C. The conductor has continuity, but additional testing
may be necessary
3
, Rationale: A continuity test establishes that an electrical path exists
between the test points. It does not necessarily establish that insulation
is intact, that the conductor is correctly identified, that polarity is
correct, or that there is no leakage to ground. Diagnostic testing must
match the suspected failure mode.
6. A 20-ohm load is connected across a 120-volt source.
Approximately how much current flows through the load?
A. 0.167 A
B. 6 A
C. 20 A
D. 140 A
Answer: B. 6 A
Rationale: Ohm's law gives I = V/R. Thus I = 120/20 = 6 amperes.
Being able to perform this calculation quickly helps an electrician
estimate expected current and recognize measurements that are
inconsistent with normal circuit operation.
7. A series circuit contains three lamps. If one lamp becomes an
open circuit, what generally happens to the current through the
series path?
A. It increases substantially
B. It remains exactly the same
C. It becomes zero through the open series path
D. It reverses direction
Answer: C. It becomes zero through the open series path
Rationale: A series circuit has a single current path. An open circuit at
any point interrupts that path and prevents current from flowing
4
