NABCEP PV Installation Professional

What is the primary purpose of a bypass diode in a photovoltaic module?

• ATo increase the module voltage output
• BTo protect shaded cells from reverse bias damage and hot spots
• CTo convert DC to AC power
• DTo regulate the charging current

According to NEC 690.7, how is the maximum system voltage of a PV array determined?

• ABy multiplying the open-circuit voltage (Voc) by the number of modules in series at STC
• BBy multiplying the Voc at STC by the temperature correction factor for the lowest expecte…
• CBy using the maximum power voltage (Vmp) at STC
• DBy using the inverter maximum input voltage rating

What is the standard test condition (STC) for PV module ratings?

• A1,000 W/m2 irradiance, 25C cell temperature, AM 1.5 spectrum
• B800 W/m2 irradiance, 20C cell temperature, AM 1.0 spectrum
• C1,000 W/m2 irradiance, 45C cell temperature, AM 1.5 spectrum
• D500 W/m2 irradiance, 25C cell temperature, AM 2.0 spectrum

What combined multiplier is commonly applied to module Isc when sizing PV source-circuit conductors under NEC 690.8(A) and 690.8(B)(1)?

• A1.0 times Isc
• B1.25 times Isc
• C1.56 times Isc
• D2.0 times Isc

What is the maximum voltage for a residential PV system per NEC Article 690?

• A300 V
• B480 V
• C600 V
• D1,000 V

What is the primary function of a Maximum Power Point Tracker (MPPT)?

• ATo convert DC to AC power
• BTo track the sun's position across the sky
• CTo continuously adjust the operating point for maximum power extraction from the array
• DTo regulate battery charging voltage

What is the minimum distance a roof-mounted PV array must be setback from a hip ridge per the International Fire Code?

• ANo setback required
• B18 inches
• C36 inches
• DIt depends on jurisdiction; the IFC requires pathways for firefighter access

What is the temperature coefficient of power (Pmax) for a typical crystalline silicon PV module?

• AApproximately +0.5%/C
• BApproximately -0.3% to -0.5%/C
• CApproximately -1.0%/C
• DTemperature has no effect on power

Per NEC 690.12, what is the maximum voltage allowed on conductors within 1 foot of the array within 30 seconds of rapid shutdown initiation?

• A30 V
• B80 V
• C120 V
• D240 V

What type of grounding is required for a PV system with a grounded current-carrying conductor?

• AEquipment grounding only
• BSystem grounding only
• CBoth equipment grounding and system grounding
• DNo grounding required for PV systems

What tool is used to measure the irradiance on the plane of a PV array during commissioning?

• AAnemometer
• BPyranometer or reference cell
• CMultimeter
• DInfrared thermometer

What is the peak sun hour (PSH) concept in solar energy?

• AThe number of hours the sun is above the horizon
• BThe equivalent number of hours at 1,000 W/m2 that produces the same total daily irradiati…
• CThe hours between 10 AM and 2 PM
• DThe hour with the highest irradiance during the day

What primarily determines the minimum size of PV source-circuit conductors under the NEC?

• AA fixed NEC rule requiring 10 AWG copper for all rooftop PV circuits
• BConductor ampacity not less than the larger of NEC 690.8(B)(1) or (B)(2) after applicable…
• CAlways matching the factory module lead wire size regardless of calculated ampacity
• DUtility interconnection agreement wire-size tables only

What is the primary advantage of microinverters compared to string inverters?

• ALower cost per watt
• BHigher overall system efficiency at full irradiance
• CModule-level MPPT reduces mismatch losses and enables panel-level monitoring
• DSimpler installation with fewer components

What is the nominal operating cell temperature (NOCT) used for?

• ATo rate the module at maximum efficiency
• BTo estimate cell temperature under more realistic outdoor conditions than STC
• CTo determine the maximum system voltage
• DTo calculate the inverter input requirements

What is the purpose of a ground fault detection and interrupter (GFDI) in a PV system?

• ATo prevent lightning damage
• BTo detect ground faults in the PV array and interrupt the fault current
• CTo measure system production
• DTo regulate voltage output

What is azimuth angle in the context of PV system design?

• AThe tilt angle of the array from horizontal
• BThe compass direction the array faces, measured clockwise from true north
• CThe angle of the sun above the horizon
• DThe angle between the array and the sun's rays

What is the recommended maximum voltage drop for PV DC circuits from the array to the inverter?

• A1%
• B2%
• C3%
• D5%

What is the minimum roof structural requirement for mounting a typical flush-mount residential PV system?

• AThe roof must support an additional 5 psf dead load
• BThe roof must be able to support the additional dead load of the PV system (typically 2.5…
• CAll roofs can support PV systems without structural analysis
• DThe roof must be rated for 100 psf live load

What type of wire is typically required for exposed PV source circuit wiring on a rooftop?

• ANM-B (Romex)
• BUSE-2 or PV Wire
• CTHHN in conduit only
• DAny UL-listed cable

How does increasing the tilt angle of a PV array above the latitude angle affect annual energy production?

• AIt always increases annual production
• BIt increases winter production but decreases summer production, potentially reducing annu…
• CIt has no effect on annual production
• DIt only affects morning production

What is the function of a blocking diode in a PV system?

• ATo prevent current from flowing back into the array from the battery at night
• BTo increase the voltage of the array
• CTo protect against lightning strikes
• DTo limit the maximum current output

What is the anti-islanding function of a grid-tied inverter?

• APreventing the inverter from overheating
• BEnsuring the inverter shuts down when the utility grid loses power
• CMaximizing energy harvest during peak hours
• DPreventing voltage spikes from reaching the grid

What is the optimal string sizing consideration when designing a PV array for a string inverter?

• AUse as many modules as possible in one long string
• BMatch the string Voc (at coldest temperature) below the inverter maximum input voltage an…
• CUse the shortest possible strings to minimize voltage
• DUse only one module per string

What is the difference between irradiance and insolation?

• AThey are the same measurement
• BIrradiance is instantaneous power (W/m2); insolation is energy over time (kWh/m2/day)
• CIrradiance is measured annually; insolation is measured daily
• DIrradiance applies to direct beam only; insolation includes diffuse

What NEC requirement applies to the disconnecting means for a PV system?

• AA disconnect is only required at the inverter
• BA PV system disconnect must be installed at an accessible location and clearly labeled
• CNo disconnect is required for systems under 600V
• DOnly a circuit breaker is acceptable as a disconnect

What is the typical efficiency range of modern monocrystalline silicon PV modules?

• A10-14%
• B15-18%
• C19-23%
• D25-30%

Per NEC 690.31, what type of wiring method is required for PV circuits inside a building?

• AOpen wiring on insulators
• BApproved raceways, cable trays, or Type MC cable
• CAny wiring method approved by the AHJ
• DOnly rigid metal conduit

What is the degradation rate of a typical crystalline silicon PV module?

• A0.2-0.5% per year
• B1-2% per year
• C3-5% per year
• DNo degradation occurs in crystalline silicon

What is the purpose of a combiner box in a PV system?

• ATo combine AC output from multiple inverters
• BTo combine multiple PV source circuit conductors into a single PV output circuit
• CTo house the battery management system
• DTo provide grounding for the array

When are string-level fuses required in a PV combiner box per NEC 690.9?

• AAlways, regardless of the number of strings
• BWhen three or more strings are connected in parallel
• COnly for systems over 10 kW
• DWhen the available fault current from parallel strings exceeds the module series fuse rat…

What is the purpose of an I-V curve trace in PV system commissioning?

• ATo measure the insulation resistance of the wiring
• BTo verify module or string performance by plotting current vs. voltage characteristics
• CTo measure the AC output quality
• DTo test the grounding system

What is the main purpose of a site survey before designing a PV system?

• ATo determine the customer's electricity rate
• BTo assess solar access, roof condition, structural capacity, electrical infrastructure, a…
• CTo negotiate the price with the customer
• DTo file interconnection paperwork

What is the NEC requirement for PV system labeling at the main service panel?

• ANo labeling is required
• BA label indicating the PV system rated AC output current and operating voltage
• CA permanent plaque or label at the main service panel indicating the PV power source, rat…
• DOnly a generic solar warning label

What does the 120% rule (NEC 705.12(B)(2)) address for PV interconnection?

• AThe maximum number of modules allowed
• BThe maximum PV backfeed breaker size relative to the bus bar rating
• CThe maximum system voltage
• DThe maximum conductor length

What is the solar window for optimal PV production in the Northern Hemisphere?

• ASunrise to sunset
• B10 AM to 2 PM solar time (4 hours)
• C9 AM to 3 PM solar time (6 hours)
• D8 AM to 4 PM solar time (8 hours)