Virginia Alternative Energy Systems Qualified Individual Examination

Under 18VAC50-22-30, what work does Virginia alternative energy system contracting (AES) authorize?

• AInstallation, repair, or improvement, from the customer's meter, of alternative energy ge…
• BInstallation of utility generation and primary distribution ahead of the customer's meter
• CInstallation of emergency generators powered by diesel or natural gas
• DAll electrical, plumbing, gas-fitting, and HVAC work needed to serve any energy system

A homeowner asks an AES contractor to install a diesel emergency generator for power outages. What is the correct AES-scope response?

• AAES covers the generator because it is a supplemental energy system annexed to real prope…
• BAES does not include installation of emergency generators powered by fossil fuels
• CAES may install the diesel generator if it is placed after the customer's meter
• DAES may install the generator if an ELE contractor later sets the service meter

Which functions does 18VAC50-22-30 say the AES specialty does not provide?

• ARacking, collectors, and associated alternative-energy equipment annexed to real property
• BRepair of existing photovoltaic arrays from the customer's meter
• CElectrical, plumbing, gas-fitting, or HVAC functions
• DInstallation of solar thermal collectors as alternative energy equipment

How does the AES customer-meter limit differ from highway/heavy (H/H) generation work?

• AAES and H/H both install utility-owned generation on the street side of the meter
• BAES works from the customer's meter; H/H may install generation and distribution ahead of…
• CAES is limited to fossil emergency generators; H/H is limited to rooftop solar
• DAES replaces the need for any other classification once the array is behind the meter

A project includes a rooftop photovoltaic array and a new utility service meter with new service-entrance conductors. What may the AES contractor perform?

• AThe array and associated AES equipment from the customer's meter, but not the service-met…
• BThe service meter, service-entrance conductors, and the array, because AES includes all e…
• COnly the utility-owned overhead drop ahead of the meter
• DThe service meter if the AES qualified individual also holds no other license

A contract lists three items: (1) rooftop PV modules and racking from the customer meter, (2) a new dwelling service panel and feeder, and (3) replacement of the central air-handler and condensing unit. How should the trades be assigned under Virginia contractor classifications?

• AAES may perform all three items because they support an alternative energy project
• BAES may perform item 1; ELE performs item 2; HVA performs item 3
• CROC may perform items 1 and 2; HVA performs item 3
• DELE may perform items 1 and 3 because both connect to electricity

18VAC50-22-30 states that no other classification or specialty provides the AES function. What does that mean for a firm that holds only ELE or only ROC?

• AELE or ROC alone may install alternative energy generation systems from the customer's me…
• BThe firm must hold AES (or otherwise qualify for that specialty) to provide the AES funct…
• CAny Class A contractor may perform AES work without the AES specialty
• DROC may install PV arrays because they attach to roofs

What work does roofing contracting (ROC) authorize compared with AES?

• AROC installs alternative energy generation systems; AES only patches shingles
• BROC installs, repairs, removes, or improves materials that form a watertight, weather-res…
• CROC and AES are interchangeable on any roof-mounted PV project
• DROC includes electrical interconnection of PV systems

Under 18VAC50-22-61, which alternative path can qualify an AES qualified individual without relying only on AES experience plus the AES exam?

• AHold any Class C license and complete a one-day OSHA card
• BQualify and obtain the roofing contracting (ROC) specialty by examination and complete NA…
• CHold an ELE master tradesman license only
• DInstall one fossil-fuel emergency generator as a demonstration project

Does 18VAC50-22-61 require a board-approved examination for the AES qualified individual on the standard experience path?

• ANo; AES has no examination
• BYes; AES lists a board-approved examination
• COnly if the firm also wants an ELE classification
• DOnly for fossil-fuel generator work

An AES firm will set glazed solar-thermal collectors and a roof rack. The owner also wants the collectors tied into the dwelling's potable water piping and a new gas-fired backup boiler. What is outside AES?

• ASetting the collectors and AES-associated racking from the customer's meter
• BThe potable-water plumbing tie-in and the gas-fired boiler/HVAC-gas functions
• CAny work on a solar thermal collector because AES is PV-only
• DOnly the racking, because collectors are an HVA function

A customer wants a natural-gas emergency generator interlocked with a rooftop PV array. Which statement is correct for an AES-only contractor?

• AAES may install both the gas generator and the PV array
• BAES may install the customer-meter PV equipment but not the fossil-fuel emergency generat…
• CAES may install the gas generator if it sits after the meter
• DAES may run the gas piping if a plumber later sets the meter

On the standard AES experience path, what minimum AES-specialty experience must the qualified individual document for a Class B firm?

• AOne year
• BThree years
• CFive years
• DNo experience if the firm holds ROC

What minimum specialty experience must an AES qualified individual document for a Class A firm on the standard path?

• AOne year
• BThree years
• CFive years
• DEight years plus an ELE master license

What irradiance is used for standard test conditions (STC) on a PV module nameplate?

• A100 W/m²
• B500 W/m²
• C1000 W/m²
• D1500 W/m²

What cell temperature is used for STC module ratings?

• A0°C
• B25°C
• C47°C
• D75°C

When identical PV modules are wired in series, what happens to voltage and current?

• AVoltages add; current stays essentially that of one module
• BCurrents add; voltage stays that of one module
• CBoth voltage and current add
• DBoth voltage and current stay the same as one module

When identical PV strings are wired in parallel, what happens to voltage and current?

• AVoltages add; current stays that of one string
• BCurrents add; voltage stays essentially that of one string
• CVoltage and current both divide by the number of strings
• DCurrent becomes zero unless an inverter is connected

In Virginia (northern hemisphere), which roof azimuth generally maximizes annual PV production if tilt and shading are equal?

• ATrue north
• BTrue south
• CDue magnetic east with no declination correction
• DTrue west, because afternoon rates are always highest

A crew turns the inverter off at noon on a clear day. What is true of the PV modules?

• AThe modules are fully de-energized because the inverter is off
• BThe modules still produce DC voltage whenever they are illuminated
• CModule voltage exists only at night
• DModule voltage disappears as soon as AC breakers are opened

How does colder cell temperature typically affect crystalline-silicon module open-circuit voltage (Voc)?

• AVoc falls as temperature falls
• BVoc rises as temperature falls
• CVoc is independent of temperature
• DVoc becomes zero below 25°C

If plane-of-array irradiance drops from 1000 W/m² to about 500 W/m² and temperature is unchanged, what happens to module short-circuit current (Isc)?

• AIsc stays the same because current depends only on voltage
• BIsc roughly halves because current tracks irradiance
• CIsc doubles
• DIsc becomes zero whenever irradiance is below STC

What is the main purpose of bypass diodes in a crystalline PV module?

• ATo convert DC to AC inside the module frame
• BTo provide an alternate current path around a shaded or damaged cell group so the rest of…
• CTo increase open-circuit voltage on cold mornings
• DTo replace equipment grounding

A residential array uses 20 modules rated 400 W STC each. What is the array's nameplate DC power?

• A0.8 kW
• B4.0 kW
• C8.0 kW
• D80 kW

Each module plus its planned gap occupies 21 ft² of roof. How much roof area do 24 modules occupy?

• A252 ft²
• B456 ft²
• C504 ft²
• D840 ft²

A site in central Virginia is near 38°N latitude. As a common annual-energy rule of thumb, what fixed tilt is closest to maximum year-round production for a true-south array with no shading?

• A0° (flat)
• BAbout 38°
• C90° (vertical wall)
• D15° facing true north

A string uses 12 identical modules with STC Voc of 49 V each. Ignoring temperature correction, what is the string open-circuit voltage?

• A49 V
• B294 V
• C588 V
• D1,176 V

An inverter's maximum DC input voltage is 600 V. Each module's design Voc, already temperature-corrected, is 48 V. What is the maximum whole number of those modules in one series string?

• A10
• B12
• C13
• D15

Three identical parallel strings each have Imp = 10.5 A. What is the combined array operating current at that condition?

• A10.5 A
• B21.0 A
• C31.5 A
• D94.5 A

A true-south array is not available. The best remaining unshaded roof faces about 40° west of true south at a reasonable tilt. What is the most accurate production expectation?

• AThe array will produce essentially nothing
• BAnnual energy will usually remain a large fraction of a true-south array; shade and tilt…
• CThe array must be rebuilt as a north-facing array to recover the loss
• DAny azimuth other than true south is prohibited by the AES specialty

A designer wants 9.6 kWdc using 400 W STC modules. How many modules are required?

• A16
• B20
• C24
• D40

A ground-mounted array in Virginia is laid out in multiple south-facing rows. What is the main reason to leave north–south inter-row spacing?

• ATo raise winter-morning string Voc
• BTo reduce row-to-row shading, especially when the sun is low in winter
• CTo convert the array from DC to AC without an inverter
• DTo satisfy the AES fossil-generator rule

What is the basic job of a PV inverter?

• AConvert array DC electricity to AC electricity for on-site use or export
• BConvert sunlight directly into hot water
• CIncrease module Voc on cold mornings
• DReplace the utility service meter

Where does a microinverter convert power compared with a string inverter?

• AAt the utility transformer ahead of the customer's meter
• BAt or on the module, producing AC from each module or small group
• COnly inside a fossil-fuel generator
• DOnly in the water heater

What does maximum power point tracking (MPPT) do?

• AHolds the array at the voltage and current that yield the most power under present condit…
• BLocks the array at STC Voc all day
• CConverts AC back to DC only at night
• DSets the utility service-meter multiplier

A grid-tied inverter without batteries sees a utility outage. What should it do?

• AKeep exporting AC to the dead utility lines so neighbors have power
• BCease exporting AC to the grid so it does not island and energize utility lines
• CStart a diesel emergency generator automatically because AES includes fossil backup
• DClose the customer's service meter bypass

A roof has mixed orientations and scattered chimney shade. Which inverter strategy best limits shade on one module from cutting an entire DC string?

• AOne long series string into a single string inverter with no module-level electronics
• BModule-level conversion or power electronics, such as microinverters or DC optimizers
• CRemoving all bypass diodes
• DConnecting the shaded modules ahead of the utility meter

How does a typical DC power optimizer architecture differ from a microinverter architecture?

• AOptimizers convert to AC at the module; microinverters only condition DC
• BOptimizers condition DC at the module and still feed a string inverter; microinverters pr…
• CBoth devices replace the utility service meter
• DOptimizers are only used on fossil emergency generators

An array is 10 kWdc and the inverter is rated 8 kWac. What is the DC-to-AC ratio, and what happens in bright cool conditions?

• ARatio 0.80; the inverter will always produce 10 kWac
• BRatio 1.25; the inverter may clip AC output near its 8 kWac rating while the extra DC is…
• CRatio 18; the inverter will be damaged whenever the sun shines
• DRatio 1.25; the extra 2 kW automatically becomes a fossil emergency generator

What distinguishes a hybrid (storage-ready) inverter from a simple battery-less grid-tied inverter?

• AThe hybrid unit can manage a battery and selected backup loads; the simple grid-tied unit…
• BThe hybrid unit is a diesel generator
• CThe simple grid-tied unit always includes a 48 V battery bank
• DOnly the simple grid-tied unit may be installed from the customer's meter

An AES crew will set a wall-mounted string inverter. The plan also shows a new back-fed breaker in the service panel and a utility meter-socket adapter. What is the AES-scope limit?

• AAES may set the inverter as associated AES equipment but does not provide the service-pan…
• BAES may land the back-fed breaker and replace the meter socket because the inverter is ne…
• CAES may do the meter-socket adapter but not the inverter
• DAES may perform all service electrical work if the inverter is listed

Estimate daily AC energy for an 8 kWdc array with 4.5 peak sun hours and a 0.80 system derate.

• A14.4 kWh/day
• B28.8 kWh/day
• C36.0 kWh/day
• D144 kWh/day

On a cool, clear midday, a 12 kWdc array into a 10 kWac inverter shows AC output stuck near 10 kW while DC input capability is higher. What is the most likely explanation?

• AThe modules have failed open
• BThe inverter is clipping at its AC rating
• CThe array is operating at night
• DThe utility meter has converted the system to a fossil generator

A string's cold-weather Voc is expected to be 580 V. Inverter A accepts up to 550 V DC; inverter B accepts up to 600 V DC. Which statement is correct?

• AEither inverter is acceptable because STC voltage is lower than 580 V
• BInverter B can be considered; inverter A is over its DC voltage limit on a cold morning
• CBoth inverters will raise their voltage limits automatically
• DAES contractors may ignore inverter voltage windows because AES includes all electrical f…

In a PV-plus-storage system, what do the batteries store?

• AAC from the utility meter socket
• BDC electrical energy for later conversion or DC use
• CDiesel fuel for an AES emergency generator
• DPotable water heated by the inverter