2026 UPDATED QUESTIONS DOWNLOAD
VA Alternative Energy System Contracting
Practice Exam 2026
Master the Virginia AES specialty exam with this comprehensive -question practice set specifically
updated for the 2026-2027 cycle. This resource covers high-yield topics including NEC Article 690
(Solar PV), Rapid Shutdown requirements, battery storage (ESS), and Virginia Residential Code
(VRC) roof setbacks. Each question features a detailed italicized rationale to ensure you understand
the electrical theory and safety standards required to pass your PSI trade exam on the first try.
1. According to NEC Article 690.7, what is the maximum DC voltage allowed for a PV
string on a one- or two-family dwelling?
A. 120 Volts
B. 600 Volts
C. 1,000 Volts
D. 1,500 Volts
Rationale: B. 600 Volts. For residential systems, the DC voltage is capped at 600V for safety;
commercial systems can go up to 1,000V or 1,500V.
2. A "Rapid Shutdown" switch for a residential PV system must reduce the voltage
within the array boundary to 80 volts or less within how many seconds of initiation?
A. 10 seconds
B. 30 seconds
C. 60 seconds
D. 5 minutes
Rationale: B. 30 seconds. This is a critical firefighter safety requirement to ensure conductors
are not "hot" during emergency operations.
3. In Virginia, what is the minimum required width of a clear access pathway on a roof
for firefighter ventilation?
A. 12 inches
B. 24 inches
C. 36 inches
D. 48 inches
Rationale: C. 36 inches. The Virginia Residential Code (VRC) requires 3-foot pathways along
the eaves and ridges to allow for safe foot traffic and ventilation.
4. Which type of conductor is specifically rated for outdoor use and exposure to
sunlight in PV source circuits?
A. THHN
B. NM-B (Romex)
C. PV Wire or USE-2
, 2026 UPDATED QUESTIONS DOWNLOAD
D. Cat5e
Rationale: C. PV Wire or USE-2. These are the only conductors designed to withstand the high
temperatures and UV radiation found on rooftops.
5. "Anti-Islanding" is a mandatory feature of grid-tie inverters designed to:
A. Increase power production.
B. Prevent the PV system from back-feeding the utility grid during a power outage.
C. Protect the panels from bird droppings.
D. Charge the batteries faster.
Rationale: B. Preventing back-feeding protects utility workers who are repairing the lines
during an outage.
6. A "PV Output Circuit" consists of the conductors between:
A. The panels and the combiner box.
B. The DC combiner and the inverter.
C. The inverter and the service panel.
D. The battery and the controller.
Rationale: B. Conductors from the combiner to the inverter are the "Output" circuits;
conductors from the panels to the combiner are "Source" circuits.
7. When calculating the maximum current of a PV circuit, you must multiply the Short-
Circuit Current (Isc) by:
A. 80%
B. 100%
C. 125%
D. 156% (125% x 125%)
Rationale: D. 156%. NEC 690.8 requires applying a 125% factor for the "maximum current"
and another 125% factor for "continuous load" (1.25 x 1.25 = 1.56).
8. Which device is used to parallel multiple strings of PV modules and usually contains
overcurrent protection (fuses)?
A. Inverter
B. Charge Controller
C. Combiner Box
D. Transformer
Rationale: C. Combiner Box. This is where multiple DC strings are brought together before
going to the inverter.
9. "Galvanic Corrosion" is a major concern when:
A. Aluminum mounting racks are in direct contact with copper grounding wire.
B. It rains.
C. The sun is too bright.
D. Using plastic conduit.
, 2026 UPDATED QUESTIONS DOWNLOAD
Rationale: A. Contact between dissimilar metals (Aluminum and Copper) leads to corrosion;
bimetallic connectors or stainless steel washers are required.
10. According to OSHA, fall protection (harnesses/anchors) is required when working at
a height of:
A. 4 feet
B. 6 feet
C. 10 feet
D. 15 feet
Rationale: B. 6 feet. OSHA 1926.501 requires fall protection for residential construction at or
above 6 feet.
11. A "Microinverter" performs what primary function?
A. Stores energy in a battery.
B. Converts DC to AC at the individual module level.
C. Tracks the sun’s movement.
D. Increases the wind speed.
Rationale: B. Microinverters allow each panel to operate independently, maximizing efficiency
in shaded conditions.
12. The "Azimuth" of a solar array in Virginia should ideally be:
A. 0° (North)
B. 90° (East)
C. 180° (True South)
D. 270° (West)
Rationale: C. 180° (True South). This provides the maximum daily sun exposure in the
northern hemisphere.
13. "STC" (Standard Test Conditions) for PV modules includes an irradiance level of:
A. 500 W/m²
B. 1,000 W/m²
C. 1,500 W/m²
D. 2,000 W/m²
Rationale: B. 1,000 Watts per square meter is the industry benchmark for testing panel
performance.
14. What is the purpose of a "Bypass Diode" inside a PV module?
A. To convert AC to DC.
B. To allow current to bypass shaded cells, preventing "hot spots" and power loss.
C. To turn off the system at night.
D. To ground the frame.
Rationale: B. Bypass diodes are critical for minimizing the impact of partial shading.
15. "Ampacity" is defined as:
A. The voltage of the system.
, 2026 UPDATED QUESTIONS DOWNLOAD
B. The maximum current a conductor can carry continuously without exceeding its temperature
rating.
C. The speed of the electrons.
D. The length of the wire.
Rationale: B. Correct wire sizing (ampacity) is essential to prevent electrical fires.
16. A "Charge Controller" is required in which type of system?
A. Grid-tie only (no batteries).
B. Battery-based (Off-grid or Hybrid).
C. Wind turbines only.
D. It is never required.
Rationale: B. The controller prevents the batteries from being overcharged by the solar panels.
17. "Net Metering" in Virginia allows a customer to:
A. Use power for free.
B. Receive a credit for excess electricity sent back to the utility grid.
C. Bypass the electrical meter.
D. Buy panels from the government.
Rationale: B. Net metering essentially uses the grid as a giant "battery" for the homeowner.
18. What is the maximum "Voltage Drop" recommended for a PV system's efficiency?
.A. 1%
B. 3%
C. 5%
D. 10%
Rationale: B. 3%. Keeping voltage drop low ensures the maximum amount of generated power
reaches the load.
19. "VOC" (Voltage Open Circuit) is the voltage measured when:
A. The system is under full load.
B. The panels are disconnected from the circuit (no current flow).
C. It is midnight.
D. The battery is full.
Rationale: B. VOC is used to determine the maximum string length an inverter can handle.
20. Which type of battery is most commonly used in modern "Energy Storage Systems"
(ESS)?
A. Lead-Acid
B. Lithium Iron Phosphate (LFP)
C. Nickel-Cadmium
D. Alkaline
VA Alternative Energy System Contracting
Practice Exam 2026
Master the Virginia AES specialty exam with this comprehensive -question practice set specifically
updated for the 2026-2027 cycle. This resource covers high-yield topics including NEC Article 690
(Solar PV), Rapid Shutdown requirements, battery storage (ESS), and Virginia Residential Code
(VRC) roof setbacks. Each question features a detailed italicized rationale to ensure you understand
the electrical theory and safety standards required to pass your PSI trade exam on the first try.
1. According to NEC Article 690.7, what is the maximum DC voltage allowed for a PV
string on a one- or two-family dwelling?
A. 120 Volts
B. 600 Volts
C. 1,000 Volts
D. 1,500 Volts
Rationale: B. 600 Volts. For residential systems, the DC voltage is capped at 600V for safety;
commercial systems can go up to 1,000V or 1,500V.
2. A "Rapid Shutdown" switch for a residential PV system must reduce the voltage
within the array boundary to 80 volts or less within how many seconds of initiation?
A. 10 seconds
B. 30 seconds
C. 60 seconds
D. 5 minutes
Rationale: B. 30 seconds. This is a critical firefighter safety requirement to ensure conductors
are not "hot" during emergency operations.
3. In Virginia, what is the minimum required width of a clear access pathway on a roof
for firefighter ventilation?
A. 12 inches
B. 24 inches
C. 36 inches
D. 48 inches
Rationale: C. 36 inches. The Virginia Residential Code (VRC) requires 3-foot pathways along
the eaves and ridges to allow for safe foot traffic and ventilation.
4. Which type of conductor is specifically rated for outdoor use and exposure to
sunlight in PV source circuits?
A. THHN
B. NM-B (Romex)
C. PV Wire or USE-2
, 2026 UPDATED QUESTIONS DOWNLOAD
D. Cat5e
Rationale: C. PV Wire or USE-2. These are the only conductors designed to withstand the high
temperatures and UV radiation found on rooftops.
5. "Anti-Islanding" is a mandatory feature of grid-tie inverters designed to:
A. Increase power production.
B. Prevent the PV system from back-feeding the utility grid during a power outage.
C. Protect the panels from bird droppings.
D. Charge the batteries faster.
Rationale: B. Preventing back-feeding protects utility workers who are repairing the lines
during an outage.
6. A "PV Output Circuit" consists of the conductors between:
A. The panels and the combiner box.
B. The DC combiner and the inverter.
C. The inverter and the service panel.
D. The battery and the controller.
Rationale: B. Conductors from the combiner to the inverter are the "Output" circuits;
conductors from the panels to the combiner are "Source" circuits.
7. When calculating the maximum current of a PV circuit, you must multiply the Short-
Circuit Current (Isc) by:
A. 80%
B. 100%
C. 125%
D. 156% (125% x 125%)
Rationale: D. 156%. NEC 690.8 requires applying a 125% factor for the "maximum current"
and another 125% factor for "continuous load" (1.25 x 1.25 = 1.56).
8. Which device is used to parallel multiple strings of PV modules and usually contains
overcurrent protection (fuses)?
A. Inverter
B. Charge Controller
C. Combiner Box
D. Transformer
Rationale: C. Combiner Box. This is where multiple DC strings are brought together before
going to the inverter.
9. "Galvanic Corrosion" is a major concern when:
A. Aluminum mounting racks are in direct contact with copper grounding wire.
B. It rains.
C. The sun is too bright.
D. Using plastic conduit.
, 2026 UPDATED QUESTIONS DOWNLOAD
Rationale: A. Contact between dissimilar metals (Aluminum and Copper) leads to corrosion;
bimetallic connectors or stainless steel washers are required.
10. According to OSHA, fall protection (harnesses/anchors) is required when working at
a height of:
A. 4 feet
B. 6 feet
C. 10 feet
D. 15 feet
Rationale: B. 6 feet. OSHA 1926.501 requires fall protection for residential construction at or
above 6 feet.
11. A "Microinverter" performs what primary function?
A. Stores energy in a battery.
B. Converts DC to AC at the individual module level.
C. Tracks the sun’s movement.
D. Increases the wind speed.
Rationale: B. Microinverters allow each panel to operate independently, maximizing efficiency
in shaded conditions.
12. The "Azimuth" of a solar array in Virginia should ideally be:
A. 0° (North)
B. 90° (East)
C. 180° (True South)
D. 270° (West)
Rationale: C. 180° (True South). This provides the maximum daily sun exposure in the
northern hemisphere.
13. "STC" (Standard Test Conditions) for PV modules includes an irradiance level of:
A. 500 W/m²
B. 1,000 W/m²
C. 1,500 W/m²
D. 2,000 W/m²
Rationale: B. 1,000 Watts per square meter is the industry benchmark for testing panel
performance.
14. What is the purpose of a "Bypass Diode" inside a PV module?
A. To convert AC to DC.
B. To allow current to bypass shaded cells, preventing "hot spots" and power loss.
C. To turn off the system at night.
D. To ground the frame.
Rationale: B. Bypass diodes are critical for minimizing the impact of partial shading.
15. "Ampacity" is defined as:
A. The voltage of the system.
, 2026 UPDATED QUESTIONS DOWNLOAD
B. The maximum current a conductor can carry continuously without exceeding its temperature
rating.
C. The speed of the electrons.
D. The length of the wire.
Rationale: B. Correct wire sizing (ampacity) is essential to prevent electrical fires.
16. A "Charge Controller" is required in which type of system?
A. Grid-tie only (no batteries).
B. Battery-based (Off-grid or Hybrid).
C. Wind turbines only.
D. It is never required.
Rationale: B. The controller prevents the batteries from being overcharged by the solar panels.
17. "Net Metering" in Virginia allows a customer to:
A. Use power for free.
B. Receive a credit for excess electricity sent back to the utility grid.
C. Bypass the electrical meter.
D. Buy panels from the government.
Rationale: B. Net metering essentially uses the grid as a giant "battery" for the homeowner.
18. What is the maximum "Voltage Drop" recommended for a PV system's efficiency?
.A. 1%
B. 3%
C. 5%
D. 10%
Rationale: B. 3%. Keeping voltage drop low ensures the maximum amount of generated power
reaches the load.
19. "VOC" (Voltage Open Circuit) is the voltage measured when:
A. The system is under full load.
B. The panels are disconnected from the circuit (no current flow).
C. It is midnight.
D. The battery is full.
Rationale: B. VOC is used to determine the maximum string length an inverter can handle.
20. Which type of battery is most commonly used in modern "Energy Storage Systems"
(ESS)?
A. Lead-Acid
B. Lithium Iron Phosphate (LFP)
C. Nickel-Cadmium
D. Alkaline
