Virginia Alternative Energy System Contracting (AES) Specialty
Actual Exam latest questions and answers graded A+ | INSTANT
PDF DOWNLOAD
Coverage: Photovoltaic (PV) Systems, Wind Turbines, Solar Thermal, Electrical
Theory, Estimating, and OSHA Safety
1. What is the primary function of a blocking diode in a PV system?
A. To convert AC to DC
B. To prevent reverse current flow from a battery to the PV array at night
C. To increase the voltage of the array
D. To regulate the battery's state of charge
Blocking diodes prevent batteries from discharging back through the PV modules during
periods of low or no sunlight, protecting the battery's stored energy.
2. Which of the following defines "STC" (Standard Test Conditions) for a solar
module?
A. 1000 W/m², 20°C ambient, 1.5 AM
B. 1000 W/m², 25°C cell temperature, 1.5 AM
C. 800 W/m², 45°C cell temperature, 1.0 AM
D. 1200 W/m², 0°C cell temperature, 2.0 AM
STC is the laboratory standard used to rate modules: 1000 Watts per square meter
irradiance, 25°C cell temperature, and an Air Mass of 1.5.
3. In a grid-tied PV system, what is the purpose of the "Rapid Shutdown"
requirement?
A. To protect the inverter from power surges
B. To improve the energy efficiency of the system
C. To ensure the safety of first responders by reducing voltage at the array
D. To disconnect the system during a utility blackout automatically
NEC 690.12 requires rapid shutdown to de-energize conductors outside the array
boundary to a safe level (30V or less) within 30 seconds for firefighter safety.
4. Calculate the total power (Watts) of a PV array consisting of 12 modules, each
rated at 320 Watts.
,A. 2,560 W
B. 3,200 W
C. 3,840 W
D. 4,120 W
The total wattage is found by multiplying the number of modules by the individual
module rating ( Watts).
5. When sizing a conductor for a PV source circuit, why is a 125% multiplier
applied to the maximum current?
A. To account for voltage drop
B. To handle battery charging surges
C. To account for continuous operation and varying irradiance levels
D. To compensate for inverter efficiency losses
PV systems are considered continuous duty (operating for 3 hours or more); the 125%
multiplier ensures the wire can handle peak current without overheating.
6. According to Ohm's Law, if the resistance in a circuit is doubled while the
voltage remains constant, the current will:
A. Double
B. Stay the same
C. Be reduced by half
D. Quadruple
Using the formula, if the denominator () increases, the resulting current ) decreases
proportionally.
7. Which tool is specifically used to measure the insulation resistance of a
conductor to check for leaks or shorts?
A. Multimeter
B. Megohmmeter (Megger)
C. Clamp meter
D. Hydrometer
A megohmmeter applies high voltage to test the integrity of wire insulation, identifying
breakdowns that a standard multimeter cannot detect.
8. What is the primary difference between a HAWT and a VAWT wind turbine?
A. The type of generator used
B. The orientation of the axis of rotation (horizontal vs. vertical)
C. The maximum speed of the wind they can handle
D. One is for residential and one is for utility-scale
,HAWT stands for Horizontal Axis Wind Turbine (the common propeller style); VAWT
stands for Vertical Axis Wind Turbine (egg-beater style).
9. "Betz’s Law" states that no wind turbine can capture more than what
percentage of the kinetic energy in wind?
A. 40.2%
B. 59.3%
C. 75.0%
D. 90.1%
This is the theoretical maximum efficiency limit for wind energy extraction; any turbine
exceeding this would theoretically stop the wind entirely.
10. What is the primary purpose of a "Lockout/Tagout" (LOTO) procedure during
maintenance?
A. To prevent the theft of solar panels
B. To ensure equipment is safely de-energized and cannot be turned back on
C. To lock the inverter settings
D. To track employee hours on a job site
LOTO is a critical OSHA safety procedure that prevents accidental re-energization of
equipment while a contractor is performing repairs or maintenance.
11. In a solar thermal system, what is the purpose of the "Expansion Tank"?
A. To store extra hot water
B. To handle the changes in fluid volume caused by temperature fluctuations
C. To increase the pressure of the pump
D. To filter the glycol
As the solar fluid (usually glycol/water) heats up, it expands; the tank provides a space
for this expansion to prevent system over-pressurization.
12. Which NEC Article specifically covers the installation requirements for Solar
Photovoltaic (PV) Systems?
A. Article 480
B. Article 680
C. Article 690
D. Article 705
Article 690 is the primary source for PV-specific requirements, including grounding,
disconnects, and wiring methods.
, 13. A "Grid-Tied" inverter is designed to automatically shut down when:
A. The sun goes down
B. The utility grid power is lost (Anti-Islanding)
C. The battery is 50% full
D. The roof is wet
Anti-islanding protection ensures the PV system doesn't feed power back into a dead
grid, which could electrocute utility workers performing repairs.
14. What is the "Tilt Angle" of a solar array?
A. The compass direction the array faces
B. The angle of the modules relative to the horizontal plane
C. The height of the modules from the ground
D. The thickness of the mounting rails
The tilt angle is adjusted to optimize energy collection based on the site's latitude and
the time of year when power is most needed.
15. According to OSHA, fall protection is required for contractors working on a
roof at heights of:
A. 4 feet or more
B. 6 feet or more
C. 10 feet or more
D. 15 feet or more
OSHA 1926.501 requires fall protection (harnesses, guardrails, or nets) for any
construction activity occurring 6 feet or more above a lower level.
16. Which of the following is the best conductor material for PV system wiring
due to its balance of conductivity and resistance to corrosion?
A. Silver
B. Aluminum
C. Copper
D. Iron
Copper is the industry standard for PV systems because it offers high conductivity and
is less prone to thermal expansion issues than aluminum.
17. What does the term "Irradiance" refer to in solar energy?
A. The power of solar radiation per unit area (W/m²)
B. The total energy delivered over a day
Actual Exam latest questions and answers graded A+ | INSTANT
PDF DOWNLOAD
Coverage: Photovoltaic (PV) Systems, Wind Turbines, Solar Thermal, Electrical
Theory, Estimating, and OSHA Safety
1. What is the primary function of a blocking diode in a PV system?
A. To convert AC to DC
B. To prevent reverse current flow from a battery to the PV array at night
C. To increase the voltage of the array
D. To regulate the battery's state of charge
Blocking diodes prevent batteries from discharging back through the PV modules during
periods of low or no sunlight, protecting the battery's stored energy.
2. Which of the following defines "STC" (Standard Test Conditions) for a solar
module?
A. 1000 W/m², 20°C ambient, 1.5 AM
B. 1000 W/m², 25°C cell temperature, 1.5 AM
C. 800 W/m², 45°C cell temperature, 1.0 AM
D. 1200 W/m², 0°C cell temperature, 2.0 AM
STC is the laboratory standard used to rate modules: 1000 Watts per square meter
irradiance, 25°C cell temperature, and an Air Mass of 1.5.
3. In a grid-tied PV system, what is the purpose of the "Rapid Shutdown"
requirement?
A. To protect the inverter from power surges
B. To improve the energy efficiency of the system
C. To ensure the safety of first responders by reducing voltage at the array
D. To disconnect the system during a utility blackout automatically
NEC 690.12 requires rapid shutdown to de-energize conductors outside the array
boundary to a safe level (30V or less) within 30 seconds for firefighter safety.
4. Calculate the total power (Watts) of a PV array consisting of 12 modules, each
rated at 320 Watts.
,A. 2,560 W
B. 3,200 W
C. 3,840 W
D. 4,120 W
The total wattage is found by multiplying the number of modules by the individual
module rating ( Watts).
5. When sizing a conductor for a PV source circuit, why is a 125% multiplier
applied to the maximum current?
A. To account for voltage drop
B. To handle battery charging surges
C. To account for continuous operation and varying irradiance levels
D. To compensate for inverter efficiency losses
PV systems are considered continuous duty (operating for 3 hours or more); the 125%
multiplier ensures the wire can handle peak current without overheating.
6. According to Ohm's Law, if the resistance in a circuit is doubled while the
voltage remains constant, the current will:
A. Double
B. Stay the same
C. Be reduced by half
D. Quadruple
Using the formula, if the denominator () increases, the resulting current ) decreases
proportionally.
7. Which tool is specifically used to measure the insulation resistance of a
conductor to check for leaks or shorts?
A. Multimeter
B. Megohmmeter (Megger)
C. Clamp meter
D. Hydrometer
A megohmmeter applies high voltage to test the integrity of wire insulation, identifying
breakdowns that a standard multimeter cannot detect.
8. What is the primary difference between a HAWT and a VAWT wind turbine?
A. The type of generator used
B. The orientation of the axis of rotation (horizontal vs. vertical)
C. The maximum speed of the wind they can handle
D. One is for residential and one is for utility-scale
,HAWT stands for Horizontal Axis Wind Turbine (the common propeller style); VAWT
stands for Vertical Axis Wind Turbine (egg-beater style).
9. "Betz’s Law" states that no wind turbine can capture more than what
percentage of the kinetic energy in wind?
A. 40.2%
B. 59.3%
C. 75.0%
D. 90.1%
This is the theoretical maximum efficiency limit for wind energy extraction; any turbine
exceeding this would theoretically stop the wind entirely.
10. What is the primary purpose of a "Lockout/Tagout" (LOTO) procedure during
maintenance?
A. To prevent the theft of solar panels
B. To ensure equipment is safely de-energized and cannot be turned back on
C. To lock the inverter settings
D. To track employee hours on a job site
LOTO is a critical OSHA safety procedure that prevents accidental re-energization of
equipment while a contractor is performing repairs or maintenance.
11. In a solar thermal system, what is the purpose of the "Expansion Tank"?
A. To store extra hot water
B. To handle the changes in fluid volume caused by temperature fluctuations
C. To increase the pressure of the pump
D. To filter the glycol
As the solar fluid (usually glycol/water) heats up, it expands; the tank provides a space
for this expansion to prevent system over-pressurization.
12. Which NEC Article specifically covers the installation requirements for Solar
Photovoltaic (PV) Systems?
A. Article 480
B. Article 680
C. Article 690
D. Article 705
Article 690 is the primary source for PV-specific requirements, including grounding,
disconnects, and wiring methods.
, 13. A "Grid-Tied" inverter is designed to automatically shut down when:
A. The sun goes down
B. The utility grid power is lost (Anti-Islanding)
C. The battery is 50% full
D. The roof is wet
Anti-islanding protection ensures the PV system doesn't feed power back into a dead
grid, which could electrocute utility workers performing repairs.
14. What is the "Tilt Angle" of a solar array?
A. The compass direction the array faces
B. The angle of the modules relative to the horizontal plane
C. The height of the modules from the ground
D. The thickness of the mounting rails
The tilt angle is adjusted to optimize energy collection based on the site's latitude and
the time of year when power is most needed.
15. According to OSHA, fall protection is required for contractors working on a
roof at heights of:
A. 4 feet or more
B. 6 feet or more
C. 10 feet or more
D. 15 feet or more
OSHA 1926.501 requires fall protection (harnesses, guardrails, or nets) for any
construction activity occurring 6 feet or more above a lower level.
16. Which of the following is the best conductor material for PV system wiring
due to its balance of conductivity and resistance to corrosion?
A. Silver
B. Aluminum
C. Copper
D. Iron
Copper is the industry standard for PV systems because it offers high conductivity and
is less prone to thermal expansion issues than aluminum.
17. What does the term "Irradiance" refer to in solar energy?
A. The power of solar radiation per unit area (W/m²)
B. The total energy delivered over a day
