NABCEP#2

With an area of 25m2 and PV modules with 12% efficiency at STC, one can install….
a. 1kW worth of power
b. 3kW worth of power
c. 2kW worth of power
d. 5kW worth of power
b. 3 kW worth of power
Net metering allows a residential home with a PV installation to …

a. receive credit for surplus energy

We Will Write a Custom Essay Specifically
For You For Only $13.90/page!


order now

b. monitor their PV system on the Internet

c. only pay for the energy their PV system produces

d. network their system to the utility company

a. receive credit for surplus
In order to maintain a 2% or less
voltage drop in designing a PV system, the following factors are all
factors except …
a. conductor size
b. combiner-to-inverter distance
c. total system current
d. back-feed breaker size
d. back-feed breaker size
When servicing lead-acid batteries, which of the following is a primary safety equipment?
a. Hydrometer
b. Gloves
c. Voltmeter
d. Goggles
d. Goggles
On a particular PV system with an operating voltage of 375VDC and 30A, the distance from the combiner box to
an inverter is 72 feet. The system design calls for using 14 A WG stranded THWN which has a resistance of 3.14ohms per k-ft.
What is the voltage drop percentage?
a. 3.6%
b. 13.6V
c. 6.78V
d. 1.8%
a. 3.6%
A 2500-W inverter is used to supply a 120 VAC load of 1500-W.
This means that the ampacity of the wire at the inverter ooutput must be at least
a. 15.6 A
b. 20.8 A
c. 26.0 A
d. 12.5 A
c. 26.0 A
The NEC definition of an interactive system is …
a. a PV system in series or parallel with the
b. a PV system that you can monitor and
c. a PV system in parallel to the grid
grid
d. a PV system in series with the grid
adjust the MPPT over the Internet
c. a PV system in parallel to the grid
grid
Before applying PV power to either an inverter, a charge controller,
batteries, or a load, one should first…
a. install the source circuit fuses
b. check the polarity of the PV output circuit
c. call the electrical inspector
d. close all disconnects
b. check the polarity of the PV output circuit
Solar noon is ….
a. always at 12:00 in the Northern
hemisphere.
b. when the sun reaches noon.
c. when the sun reaches a latitude at a given location & highest position in the sky
d. when the sun reaches a meridian at a given location & highest position in the sky
d. when the sun reaches a meridian at a given location & highest position in the sky
What is the angle of the sun or solar declination relative to the earth’s surface at solar noon at 23.5° North latitude on June 21st?
a 90°
b. 13.5°
c.57°
d. 23.5°
d.23.5 Summer Solar
Which of the following PV systems typically has the fewest components? a. remote home b. village hybrid c. direct-coupled water pumping d. grid-connected residential
c. direct-coupled water pumping
Hydrometers measure.
a. battery lead content
b. electrolyte to determine battery charge
c. voltage
d. current
b. electrolyte to determine battery charge
What is the “photovoltaic effect”?
a. Extracting electrons from the sun
b. Conversion of heat into electrical energy
c. Conversion of light into electrical energy
d. Conversion of light into heat
c. Conversion of light into electrical energy
Lag screw allowable withdrawal load is measured by …
a. Width of lag screw
b. length of the lag screw
c. tensile strength necessary to forcibly remove the lag screw
d. Number of threads in the lag screw
c. tensile strength necessary to forcibly remove the lag screw
All of the following reduce or enhance solar irradiation received at a particular location except:
a. altitude
b. ozone
c. earth’s position in relation to the sun
d. module efficiency
d. module efficiency
According to safety practices, how do you determine the proper angle to place an extension ladder to climb onto a roof?
a. The ladder should be at least 3-ft. away
b. The horizontal distance should be 1/4 the distance of the vertical line measured from the ground to where the ladder touches the roof.
c. A distance that you feel safe from the vertical line from the ground to where the ladder touches the roof.
d. While standing straight in front of the ladder with feet touching the bottom of the ladder, you should be at arm’s length from the rails.
b. The horizontal distance should be 1/4 the distance of the vertical line measured from the ground to where the ladder touches the roof.
When mounting a heavy inverter or other piece of equipment to a dry-wall type of wall, to provide a solid
attachment to the wall it may be necessary to use …
a. plywood
b. inverter mounts
c. plastic anchors
d. PV-rated moly bolts
d. PV-rated moly bolts
The purpose of the ground-fault protection device in a PV system is to …
a. reduce degradation of structural supports
c. reduce losses of the PV output energy to from rapid electrolysis ground
d. reduce the possibility of fire from an to service personnel arcing fault to ground
b. reduce the probability of electrical shock to service personnel
6 months after commissioning a system, a homeowner discovers the system is suddenly only 80% efficient. The
most likely cause for this is …
a. Voltage drop due to long cabling distance
b. Grid brown-out condition
c. Damage to a conductor by a rodent
d. Design flaws in initial system
c. Damage to a conductor by a rodent
With the PV array rack mounted at ground level, which would normally be of greatest concern?
a. Overheating of modules
b. Earthquake stresses on the modules
c. Electrical hazards from exposed open
circuit voltages
d. Physical damage to the array and wiring
d. Physical damage to the array and wiring
Captive electrolyte batteries are often referred to as …
a. VRLA batteries
b. NiCad batteries
c. Stationary batteries
d. SLI batteries
c. Stationary batteries
p162-163
The 2005 NEC allows marking conductors with colored tape, provide that they are larger than…
a. 8AWG
b. 6AWG
c. 10 AWG
d. 4AWG
a. 8AWG
According to OSHA regulations, to protect workers, toeboards shall be erected along the edge of platforms …
a. more than 6 feet above a lower level.
b. more than 12 feet above a lower level.
c. more than 10 feet above a lower level.
d. as needed
c. more than 10 feet above a lower level.
OSHA requires guardrails to be …
a. used when working 6′ or more above theground
b. 42″ high with at least 1 middle rail about halfway between the working surface & the top rail
c. 42″ high with at least 1 middle rail about halfway between the working surface & the top rail & must have a toeboard
d. 36″ high with at least 1 middle rail about
halfway between the working surface &
the top rail
c. 42″ high with at least 1 middle rail about halfway between the working surface & the top rail & must have a toeboard
A typical efficiency rating for a 4 kW inverter is …
a. dependent on the module array tilt b. typically in the high 80’s percent c. highest when operated past a certain
output
d. 95%
c. highest when operated past a certain
output
The magnetic declination of San Francisco is 15° East. At what compass degree would true South be?
a. 15°
b. 195°
c. South in San Francisco is always at 180°
d. 16So
d. 165
In a PV system, the equipment-grounding conductors should be …
a. green
b. black
c. White
d. red
a. green
If the maximum power voltage of a crystalline silicon PV module is 42.1 volts at STC, then at 2SoC and 1000
W/m2 incident on the module, the maximum power voltage will be …
a. higher than 42.1 volts
b. 42.1 volts
c. equal to the current at STC
d. lower than 42.1 volts
c. equal to the current at STC
The charge controller that limits charging current to a battery system by completely open-circuiting the array is the …
a. shunt-linear charge controller
b. series-interrupting PWM charge controller
c. shunt-interrupting charge controller
d. series-interrupting charge controller
d. series-interrupting charge controller
Sine wave inverters are required for connection to utility lines because …
a. they are the only inverters that have <5%total harmonic distortion (THD)
b. non -sine wave inverters cannot develop adequate power for utility interconnection
c.they are more efficient than other types
d. only sine wave inverters can be designed adequate power for utility interconnection to disconnect from the utility when utility power is lost
a. they are the only inverters that have <5%total harmonic distortion (THD)
A 24-volt Cal-Trans road sign has a system capacity requirement of200Ah. How many 500 Ah/12v batteries are
needed?
a. 2
b. 6
c. 1
d. 0.4
a. 2
Three series strings of 4 modules, each rated at 38.5VOC (STC) are installed in Billings, Montana with a 45° tiltangle and a 0° azimuth orientation. During the summer solstice, what is the system voltage if the ambient
temperature is 40° C and there is a total wiring voltage drop of2%?
a. 142.5 VDC
b. 150.9 VDC
c. 139.6 VDC
d. 154 VDC
c. 139.6 VDC
The output of a certain module is measured to be 48VDC at STC. At 35°C, this voltage would be closest to …
a. 50.4 VDC
b. 48 VDC
c. 43 VDC
d. 45.6 VDC
d. 45.6 VDC
The most common source of fatal electrical accidents involves …
a. Lightning
b. 3-phase wiring
c. Battery banks
d. Household current
d. household current
Lead-acid battery outgassing creates …
a. hydrogen and oxygen
b. AGM battery gas
c. electrolytic gas
d. sulfuric gas
a. hydrogen and oxygen
A 400 Ah battery will deliver __ for ___ hours before being considered fully discharge.
a. 1 A for 400 hrs.
b. all of these are correct
c. 2A for 200 hrs.
d. 4A for 100 hrs
b. all of these are correct
Inter-row spacing is determined by …
a. height of the panels at solar noon
b. sun angle & rack voltage
c. sun angle & rack angle
d. rack manufacturer specifications
c. sun angle & rack angle
When connecting and disconnecting wires while troubleshooting a PV system, the best way to avoid electrical shock is to …
a. turn off switches, measure voltages and currents, and wear protective equipment
c. keep one hand behind your back, with all switches turned off and only touchgrounded surfaces
b. wear shoes with soft rubber soles, tum off
d.all switches, and don’t touch metal
inspect all questionable terminals, wear rubber gloves, and tum off all switches surfaces
a. turn off switches, measure voltages and currents, and wear protective equipment
Step-up transformers … ?
a. decrease voltage & current
b. increase voltage & decrease current c. increase voltage & current
d. decrease voltage & increase current
c. increase voltage & current
Diodes act as which type of mechanical valve?
a. Check valve
b. Probe valve
c. Butterfly valve
d. Pressure valve
a. Check valve
Using the Solar Pathfinder on question #13, during what months will there be a shading issue between the hours
of 9:00 AM to 3:00 PM?
a. June to July
b. March to April
c. December to March
d. There will be no shading issues all year
c. December to March
If electronic equipment is to be housed in a container above the battery container with battery cables passing between the two containers, then the batteries should be of what type?
a. Any type of nickel-cadmium
b. Nickel-iron acid d. Valve-regulated lead-acid
c. Flooded lead-acid
d. Valve regulated lead-acid
a. Any type of nickel-cadmium
The continuous total current load on system wiring is determined to be 40A. The wiring, disconnects, fuses, and
circuit breakers should be sized …
a. for 50A
b. for40A
c. depending on system voltage.
d. for 32A
a. for 50A
Wiring PV panels in parallel will ___ while wiring them in series will ____ _
a. Increase amperage, increase voltage b. increase wattage, increase current c. increase voltage, increase amperage
d. maintain amperage, decrease voltage
. Increase amperage, increase voltage
The U.S Federal incentive for residential PV in 2010 is …
a. applicable only in certain states b. a 30% rebate
c. a 30% tax credit
d. a $2000 tax credit
c. a 30% tax credit
In the Northern hemisphere, which tilt angle maximizes power in the summer?
a. 90°
b. latitude -15°
c. local latitude angle
d. latitude + 15
b. latitude -15° Summer
The charge controller that limits charging current to a battery system by gradually lowering the resistance of a shunt element through which excess current flows is the …
a. series-linear charge controller
b. series-interrupting PWM charge controller
c. MPPT charge controller
d. shunt-linear charge controller
d. shunt-linear charge controller
The width of the working space in front of an inverter that is 24″ wide must be at least…same or another voltage same or another voltage
a. 42″
b. 24″
c. 30″
d. 36″
c. 30″
The NEC definition of PV source circuit is …
a. wires from combiner or junction box to inverter
b. wires from PV array to combiner or
junction box
c. all BOS wiring in a PV source system
d. wires between modules in a string but not to combiner or junction box
b. wires from PV array to combiner or
junction box
2-phase power is …
a. always 240 volts
b. none of these
c. always 110 volts
d. always 120 volts
b. none of these
A roadside emergency 911 phone uses 200Ah at 24VDC. The NiCad battery in it can discharge down to 70%
DOD but must have 7 days of autonomy. How big must the battery storage be?
a. 240
b. 1400
c. 980
d. 2000
d. 2000
This would require the greatest ampacity derating …
a. Ampacity is not derated for temperature
b. Wire not in conduit on a roof in Palm
c. A PV system in Antarctica
d. Wire in conduit on a roof in Palm Springs
Springs with 3 other current-carrying conductors
d. Wire in conduit on a roof in Palm Springs
When the sun sets on winter solstice, it is farthest than it will ever set.
a. East
b. North
c. West
d. South
d. South
Stainless-steel hardware is most important in which of the following areas?
a. Desert areas where the air contains a mix of dust
b. Inland regions that are subject to freezing
c. Coastal areas where the air contains salt mixture of dust spray
d. Mountainous areas where the solar temperatures spectrum contains more UV rays
c. Coastal areas where the air contains salt mixture of dust spray
If the grid shuts down …
a. it is highly unlikely that your modules can charge your batteries in an interactive battery backup system
b. it can cause severe damage to your
inverter if it is not grounded properly.
c.you can power the neighborhood if your neighbors agree.
d. you can help your neighborhood by
powering it.
a. it is highly unlikely that your modules can charge your batteries in an interactive battery backup system
Four modules, each with an area of 10 sq. ft., are to be mounted with a stand-off mount that is secured to a metal seam room with 6 L-brackets. If the modules can withstand a load of75lbs. per sq. ft., and if it is desired to support the full load with 1 lag screw in each bracket, and each screw has a withdrawal resistance of 300 lbs. per inch, including a safety factor of four, the minimum screw thread length that will need to
penetrate wood will be closer to …
a. 6.67″
b. 1.1″
c. 2.25″
d. 1.67
d. 1.67
4Modules
10sqft/MOD
6L Brackets/ 6 Screws
300LBS/in
75LBS/FT2/MOS
4MODSX10SQFTX75LBS if 2 = 3000lbs
300lbs/6=500lbs
500/300=1.67
A Cal-Trans road sign utilizes 1200 Wh/day with a 24-volt system. The autonomy needs to be 3 days and the battery DOD is 75%. What is the system battery capacity?
a. 150 V
b. 200 Ah
c. 150 Ah
d. 200 W
TBD email answer to [email protected]
WHOOPS…was sleeping..
The first step in system checkout after completing the installation is …
a. visually check the entire system
b. test open-circuit voltage
c. close all disconnects
d. install the source-circuit fuses
a. visually check the entire system
Summer and Winter solstices are when …
a. solar declination equals the latitude
b. solar declination is minimum & maximum
c. daylight hours equal nighttime hours
d. days and nights are equal in length
b. solar declination is minimum & maximum
In the event that the utility voltage is lost in a utility-interactive system, the inverter should …
a. no longer take DC power from the array
b. not supply power to the battery bank
c. continue to function normally
d. not supply power to the distribution panel
d. not supply power to the distribution panel
If you combine solar and wind energy in an off-grid system, it is …
a. sinusoidal
b. hybrid
c. bimodal
d. interactive
b. hybrid
The voltage drop ofa lower voltage system would be …
a. a higher percentage
b. a lower percentage & same voltage drop
c. lower amps
d. higher
a. a higher percentage
On a particular PV system with an operating voltage of 280VDC and 28A, the distance from the combiner box to
the inverter is 32′. System design calls for using 12A WG stranded THWN which has a resistance of 1.98
ohms/k-ft. What is the voltage drop percentage?
a. 1.3
b. 3.55
c. 1.77
d. 0.63
a. 1.3
A 4 kW PV system in Palm Springs has an inverter efficiency of95%, a wiring voltage drop of2%, and a temp
derating of -7.5%. The area experiences cloud shading loss of -20%, and sandy winds causing a -10% irradiance loss. What is the system output?
a. 2.48 kW
b. 2.76 kW
c. 2310 W
d. 6451 W
a. 2.48 kW
When you test a particular PV system with a multi-meter, you find there is no voltage on the AC side of the
inverter. The likely cause is …
a. homeowner is using too much power b. array was struck by lightning
c. PV breaker in distribution panel is tripped
d. dust and dirt on the array
c. PV breaker in distribution panel is tripped
Series connected modules increase …
a. voltage
b. current
c. voltage & total power
d. current & total power
c. voltage & total power
Thin-film PV modules are …
a. mostly made from silicon ingots
b. mostly made from wafers
c. more efficient than c-Si modules
d. mostly made from Cd-Te
d. mostly made from Cd-Te
Azimuth angles used in PV systems designate South at…
a. 900
b. 0
c. 1800
d. Latitude
b. 0
pg-69
What is a negative result of increased irradiance on system performance?
a. It increases cell temp & reduces efficiency
b. It can cause an over current situation
c. It makes it difficult to work on the array without gloves & eye protection
d. It can cause an over voltage situation
a. It increases cell temp & reduces efficiency
What does snow and decorative white rocks have in common with regards to PV modules?
a. they are both white
b. they both increase voltage of the cells
c. they add aesthetic appeal to an installation
d. they both increase irradiance on the panels
d. they both increase irradiance on the panels
For a PV system in a remote village in India, one would typically choose a …
a. stand-alone inverter
b. synchronous grid-tied with battery back-up
c. synchronous grid-tied inverter
d. Fronius AGM inverter
up
a. stand-alone inverter
All other considerations being equal, what type of charge controller would be best suited for a stand-alone PV
system installed in a cold climate?
a. Series charge controller
b. MPPT charge controller
c. Shunt-linear charge controller
d. Diversionary charge controller
b. MPPT charge controller
In New York City, magnetic North is pointing …
a. true north
b. more east than true north
c. more south than true north
d. more west than true north
TBD email answer to [email protected]
WHOOPS…was sleeping..
A passing score in the entry-level NABCEP exam …
a. assigns me NABCEP certification status
c. makes me certified in photovoltaic
b. allows me to use the NABCEP logo on
business cards, stationery, etc.
installations
d. will make it easier to obtain a job in the PV industry
d. will make it easier to obtain a job in the PV industry
Which of the following devices does the NEC require to be a part ofPV systems mounted on residential
dwellings?
a. An accessible source circuit combiner box
b. A ground-fault protection device
c. A stand-off mount for the modules
d. A utility interconnection
b. A ground-fault protection device
What tool measures irradiance?
a. Solar Pathfinder
b. Ampclamp
c. Cat II multimeter
d. Pyranometer
d. Pyranometer
The charge controller that suspends charging current to a battery by completely short-circuiting the array is the …
a. series-interrupting charge controller
b.shunt-interrupting charge controller
c. shunt-linear charge controller
d. series charge controller
unknown answer
Solar breaker + main breaker =
a. solar breaker should never be on the same
b. 120% of bus bar rating
c. 75% busbar rating
busbar as the main breaker
d. bus bar rating
b. 120% of bus bar rating
A solstice is when …
a. the same as an equinox
b. solar declination is equal to zero c. daytime & nighttime are equal
d. solar declination is minimum or maximum
d. solar declination is minimum or maximum
A 24-volt, stand-alone system has a daily requirement of 1600 Wh. This home requires 5-days of autonomy at
75% DOD. What is the total battery capacity requirement?
a. 444 Ah
b. 44.4 Ah
c. 76 Ah
d. 333 Ah
a. 444 Ah
A PV system is to be selected for operating a PV water pumping system. The pump will require 300W ofPV
modules for proper operation. A 12VDC model and a 48VDC model are available. Ifboth pumps operate at the
same power level, the resistance of the wire to the 12VDC pump, compared to the resistance of the wire to the
48VDC pump, assuming the same percentage voltage drop in the wiring, may be …
a. 1/16th as much
b. 1/4th as much
c. 4 times as much
d. 16 times as much
TBD
Using the Solar Pathfinder on question #13, how many hours of sun will a system receive in December between
the hours of9:00 AM and noon?
a. approximately 4
b. approximately 1.5
c. none
d a number equal to the latitude-15
b. approximately 1.5
Bypass diodes are used to …
a. perfonn the same function as a bypass diode
b. maximize power loss due to shading or module damage
c. pass current through PV cells or modules
d. pass current around PV cells or modules
d. pass current around PV cells or modules
The purpose of a linear current booster is to ..
a. keep its output current the same as its output current the same as its input current & boost the output voltage to a value larger than the input voltage
b. convert a high input voltage & low input current to a lower output voltage & a higher output current
c.convert a low input voltage & a high input current to a higher input voltage & a lower input current
d. keep its output voltage the same as its input voltage & boost the output current to a value larger than the input current
c.convert a low input voltage & a high input current to a higher input voltage & a lower input current
Which of the following situations would result in the most cost-effective use of a 2-axis tracking mount?
a. Areas of moderate wind, latitude greater
b. Areas of low wind, latitudes less than 30°
c. Areas of moderate wind, latitude less than than 30° & moderate year-round cloud 30° & minimal year-round cloud cover cover
d. Areas of low wind, latitude greater than& moderate daytime summer cloud cover 30° & minimum daytime summer cloud cover
d. Areas of low wind, latitude greater than& moderate daytime summer cloud cover 30° & minimum daytime summer cloud cover
If 3/8″ lag screws are used to fasten a charge controller to wooden studs, an appropriate pilot hole size would be
closest to …
a. 19/64″
b. 118″
c 1/4″
d. 7/32″
c 1/4″
In St. Paul, MN, the sun is up …
a. more than the number of sun hours per day part of the time
b. none of these answers
c. less than the amount of sun hours per day at the equinox
d. the same amount of hours as there sun hours per day
b. none of these answers
In order for a PV array to directly face the sun at 9:30 a.m sun time on June 21st at 30° N latitude, which array orientation is correct? (Use the sun-path diagram on question #27)

a. Directly E with a tilt of 60° with respect to
b. 60° W of S with a 60° tilt with respect to the horizontal.
c. 45° W of S with a tilt of 40° with respect the horizontal to the horizontal
d. Directly W with a tilt of 60° with respect the horizontal to the horizontal

a. Directly E with a tilt of 60° with respect to
The presence of voltage on a metal surface that can easily be accessed and can cause electrocution is referred to
as …
a. touch potential
b. not to NEC code
c. step potential
d. the result of an ungrounded system
a. touch potential
Between the distribution panel and the inverter you have ..
a. an AC disconnect
b. sometimes a charge controller
c. b & c
d. a DC disconnect
d. a DC disconnect
The length of time a load is on …
a. is inversely proportional to the power used
b. is proportional to the energy used c. is proportional to the power used
d. is proportional to amperage only if a
modified sine waveform inverter is used
b. is proportional to the energy used
If the electrolyte freezes, the battery should …
a. equalized with a high current
b. be disposed properly
c. be slowly charged with a low current
d. be slowly discharged below D.O.D
b. be disposed properly
Solar noon at the 90 degree meridian would be at…
a. 11 :00 PM standard time
b. 1 :00 PM standard time
c. 12:00 PM standard time
d. varies with latitude
b. 1 :00 PM standard time
Between the array and the inverter you can have …
a. a DC disconnect & a charge controller
b. an AC disconnect
c. a charge controller
d. a DC disconnect
a. a DC disconnect & a charge controller
A PV array tilt in Albuquerque, NM (latitude = 35.1°) is set at 35° with an azimuth of 75°. SunEye software
analysis indicates that with an azimuth of 0°, the array would deliver 95% of available irradiance in July. Since the array orientation cannot be changed, the expected output will be …
a. lower because the voltage would be
increased
b. higher because the elevation reduces air
c. lower because the current would be
increased reduced
d. the same since anything less than 90°
mass
c. lower because the current would be
increased reduced
What are watt-hours?

a. I x R
b. E x I x hrs.
c. I x Rx hrs.
d. ExI

b. E x I x hrs.
Of all the available alternative energy techonlogies in use today, which is the oldest?
a. Geothennal
b. Solar Thennal
c. Wind
d. Photovoltaic
c. wind