Photovoltaics Book Questions
when placing a ladder against a building, the: a. top of the ladder should extend at least three feet above the point where it comes in contact with the structure b. the base of the ladder should be offset from the point where it comes in contact with the building by four feet c. the ladder must incorporate fall protection if the operator is in danger of falling at least six feet from one level to another d. none of the above
a. top of the ladder should extend at least three feet above the point where it comes in contact with the structure
when climbing a ladder, always: a. use the three point climbing technique b. secure the top and bottom with a rope when there is a potential to fall more than six feet c. conduct a lock out, tag put process before mounting the first cleat d. wear ANSI approved eye protection and hard hat
a. use the three point climbing technique
ohm's law is expressed as: a. volts= current x resistance b. watts= amps x volts c. voltage drop= amps x resistance x twice the distance d. resistance= amps x volts
a. volts= current x resistance
each crystalline cell generates about ______ volts of electricity when exposed to full sunlight a. .01 volts b. .55 volts c. 12 volts d. 24 volts
b. .55 volts
a kilowatt is a. 10 watts b. 100 watts c. 1,000 watts d. 10,000 watts
c. 1,000 watts
we have to look at the book for question five of chapter 10 because it was too much for me to type loll
c. 3.73 kW * see book please *
a ______ is typically made of a semi conductor material and allows energy to flow in only one direction a. diode b. capacitor c. conductor d. insulator
a. diode
the charge controller handles the various stages of charging within deep cycle batteries. these stages typically include a. bulk, absorption, floating b. full, tapering, leveling c. equalization, absorption, floating d. equalization, leveling, absorption
a. bulk, absorption, floating
in order to avoid a significant loss of power due to shading, panel manufacturers will often place ______ in the panel wiring system a. bypass diode b. blocking diodes c. rectifying diodes d. amplifying diodes
a. bypass diode
a client wishes to increase the power output of their 5 year old solar array. which of the following options would likely be the best option (barring unusual circumstances) a. add additional panels to the system b. add an active tracking system c. replace all the solar panels with more efficient models d. add additional batteries to the system
a. add additional panels to the system
the portion of the NEC that specifically addresses photovoltaics is: a. article 690 b. chapter 250 c. section 8.5 d. NEC 2014
a. article 690
which of the following is NOT a circuit in a typical grid tied PV system a. PV input circuit b. PV output circuit c. inverter input circuit d. inverter output circuit
a. PV input circuit
when adjusting the orientation of a solar panel from east to west, this adjustment affects its a. azimuth b. altitude c. declination d. resistance
a. azimuth
a stand alone PV system has the following characteristics: a 3 kW PV array daily load demand of 10 kWh, a maximum power draw of 2 kW at any time, a 1400 Ah battery bank, a nominal battery bank voltage of 48 Vdc and 4 hours of peak sunlight. what is the minimum power rating required for this system's inverter? a. 2 kW b. 3 kW c. 10 kW d. 12 kW
a. 2 kW
an array facing solar west will likely produce about ______ energy than would be produced by the same array in the same location facing solar south a. 20% less b. 40% less c. 10% more d. 12.53% less
a. 20% less
if a #4 AWG TW conductor was placed in a conduit with 14 other similar conductors, it would now have an apmacity rating of, ( we have to look at table 5-3) a. 35 amps b. 70 amps c. 85 amps d. 95 amps
a. 35 amps * see book for full explanation *
a simple electrical drawing that uses boxes to represent the various components of a PV system and lines to represent the conductors and conduits connecting these components together is called a(n)__________ a. one line drawing b. plan view c. application package d. as built diagram
a. one line drawing
from a very practical perspective the photovoltaic industry is a. only about ten years old b. reaching a point of market saturation c. is an industry in decline d. controlled by only one or two dominant manufactures
a. only about ten years old
which of the following PV systems will need to incorporate a utility interface a. stand alone b. grid tied c. solar thermal d. direct current
b. grid tied
every solar panel has a unique power output characteristics that can be diagrammed in a chart by plotting how many watts of power are generated at each and every level of current and at every voltage. this is called _______ a. the maximum efficiency diagram b. the I-V curve c. multi junction display pattern d. manufacturer's reliability function
b. the I-V curve
when a string of batteries are connected in series: a. the voltage and amps remain the same b. the voltage increases but the amps remain the same c. the voltage remains the same, but the amps increase d. both voltage and amps increase
b. the voltage increases but the amps remain the same
when evaluating a roof for a possible PV array, which is not a consideration a. age of shingles b. structural condition of the rafters c. pitch of the roof d. its demarcation point
d. its demarcation point
if no bias is introduced into the altitude of a fixed solar panel, the angle will likely be based on a. solar south b. the azimuth c. longitude d. latitude
d. latitude
the national electric code is published every three years by the: a. national electrical commission b. national renewable energy laboratories c. national fire protection association d. North American board of certified energy practitioners
c. national fire protection association
the MAXIMUM DC nominal voltage a battery bank within a residential STAND ALONE system in the U.S. can be configured to (by code) is a. 12 volts b. 24 volts c. 50 volts d. 600 volts
c. 50 volts
a grid tied PV system has suddenly stopped working completely. which of the following is most likely the cause of such a situation a. heat fade b. shading c. a ground fault d. dirt on the modules
c. a ground fault
the place where multiple strings from an array are connected in parallel is referred to as the a. junction box b. Mc4 connector c. raceway d. combiner box
d. combiner box
to account for the inefficiencies of a PV system as the result of voltage drop, loss due to connections, inverter inefficiencies, internal battery load resistance, etc, you must ________ the estimated power output of your array a. reduce b. future proof c. insolate d. derate
d. derate
determining restrictions on the height of buildings adjacent to the property when an array is mounted might be an example of a. hazard assessment b. building integrated PV c. commissioning the system d. future proofing
d. future proofing
a weak module reacting with excessive voltage loss due to increased cell temp. is known as a. heat loss b. heat resistance c. heat drop d. heat fade
d. heat fade
the winer bias of an array is a. solar south less than 15 degrees b. the angle of declination on Dec 22nd c. the assumption that arrays produce less energy in the winter d. latitude plus 15 degrees
d. latitude plus 15 degrees
which of the following will NOT decrease the life expectancy of a battery bank in a PV system a. increase the depth of discharge b. increase the heat where they are stored c. increase the number of cycles d. increase the system voltage
d. increase the system voltage
peak sun hours is a measurement of a location's a. declination b. azimuth c. latitude d. insolation
d. insolation
a checklist of all the steps involved in installing a PV system is typically referred to as _______ a. commissioning form b. compliance form c. inspection list d. punch list
d. punch list
it has been determined that a home requires a 6.5 kW array. the homeowner has purchased 26 solar world 250 W panels from her brother in law. at her location, the temp. extremes are -37 degrees celsius (coldest) and 43 degrees celsius (hottest). her string inverter has an operating input range of 100-550 Vdc. the solar panels have the following characteristics: Voc= 37.8 V Temp. coefficient (Voc)= .30%/degree Celsius Vmp= 31.1 V temp. Coefficient (Pmax)= .45%/degree Celsius a. 4 b. 5 c. 6 d. 7
a. 4 * see book for full explanation *
the average U.S. home (in 2010) consumed 960 kWh of electricity per month. assuming 4.2 hours of insolation at the site and a .90 derate factor for the system, what size array will be required to provide all the power necessary for this home over the course of a year? a. 8.33 kW b. 6.74 kW c. 7.49 kW d. 253.97 W
a. 8.33 kW * see book for full explanation *
the capacity of a battery is generally measured in a. Ah at C20 b. number of cycles DOD c. nominal voltage d. peak charge MPPT
a. Ah at C20
to power aa 24 Vdc water pump with a 12 Vdc battery, you would need to add a(n)________ a. DC voltage converter b. charge controller c. inverter d. can't be done
a. DC voltage converter
which of the following components within a PV system is typically not considered as part of the balance of system (BOS) a. PV panel b. battery system c. disconnects d. controller
a. PV panel
to avoid electrical shocks if a ladder comes in contact with a charged conductor, ladders should a. be made of fiberglass b. be less than 24 feet tall c. be rated to carry the weight of the person climbing as well as any tools and/or material they may be carrying d. be secured at the top and at the bottom of the ladder
a. be made of fiberglass
an inverter that can function both as a grid tied inverter as well as a stand alone inverter is referred to as a(n) __________ inverter a. bimodal b. micro c. UL 1741 listed d. inter-tie
a. bimodal
EMT conduits stands for a. electrical metallic tubing b. exterior metallic tubing c. environmentally maintained tubing d. electro-mechanical tubing
a. electrical metallic tubing
a proper lockout/tag-out procedure should include all the following steps EXCEPT a. ensure all devices and disconnects are in the closed position b. attach a locking mechanism to the devices to ensure they cannot be energized by mistake c. attach a tag to the devices explaining that the device is temporarily off due to system service or maintenance d. notify all persons who may be affected that the system is about to be shut down and notify then when the system is operational once more
a. ensure all devices and disconnects are in the closed position
holes dug for footings for a ground mounted racking system must: a. extend below the frost line b. extend at least 20 inches below undisturbed soil c. extend a minimum of 5 inches beyond the circumference of the support pole d. all of the above
a. extend below the frost line
a _______ is used to pul conductors through a conduit a. fish tape b. conduit body c. cleat d. PFAS
a. fish tape
a grid tied PV system is generating less power than expected. which of the following is most likely the cause of such a situation a. heat fade b. reversed polarity c. the grid is down d. a ground fault
a. heat fade
which of the following is NOT part of a typical roof top racking system a. helical piers b. top down mounting clamp c. footings d. rails
a. helical piers
the situation where a PV system is generating power to the electrical grid while the grid id "down" (no electricity flowing from the utility) is known as a. islanding b. grid tied c. a utility interface d. band gap energy
a. islanding
_______ are made by slicing a single silicon crystal into wafers. they are generally more expensive, but are also more efficient in converting the energy of the sun into electricity a. mono crystalline cells b. multi junction pv cells c. Polycrystalline cells d. thin-film
a. mono crystalline cells
emergency shutdown procedures are an example of information that may be included in ____________ a. operational and maintenance documents b. the plan view c. the electrical permit d. commissioning forms
a. operational and maintenance documents
all of the following are common problems caused by poor design, EXCEPT: a. oversizing of wire and conduit b. a poor site survey c. failure to account for future shading d. balance of systems undersized
a. oversizing of wire and conduit
which of the following would be useful in determining if a specific site has enough sunlight available to support a PV system a. solar insolation map b. a solar window c. a declination chart d. a topographical relief diagram
a. solar insolation map
which of the following will help minimize system damage in the event of a lightning strike a. surge protection b. fuses and circuit breakers c. ground fault detection d. all of the above
a. surge protection
to determine the maximum panels allowable in a string of a grid tied array, you must know all of the following EXCEPT a. the azimuth of the array b. the coldest temp. ever experienced on the site c. the voltage input specifications of the inverter d. the temp. coefficient of the panels
a. the azimuth of the array
live loads refer to all the following EXCEPT a. the weight of the racking system b. the lift from wind passing over a panel c. the weight of snow and/or rain on the rooftop d. additional stress placed on the roof during an earthquake
a. the weight of the racking system
in a lead acid battery the battery's charge capacity a. will decrease by about 1% per degree C below 20 degrees C b. is unaffected by temp. c. will decrease by about 2% per degree C above 25 degrees C d. will undercharge in extremely high temps.
a. will decrease by about 1% per degree C below 20 degrees C
if you have a wire length of 100' in a 90 volt , 8.5 amp derated DC circuit, what is the SMALLEST wire sized you would need to use to get less than a 2% voltage drop a. #6 AWG with a resistance of .510 b. #8 AWG with a resistance of .809 c. #10. AWG with a resistance of 1.29 d. none of the above
b. #8 AWG with a resistance of .809 * see book for full explanation *
an array of 24 panels, each with an Isc of 8.35 amps, has been configured into 4 strings of 6 panels each. the wires from these strips are combined in a combiner box. assume the PV source circuit wiring has been placed in conduit that is exposed to sunlight and is mounted directly to the deck of the roof. these conduits run to a combiner box mounted so that it is never exposed to sunlight. what is the minimum ampacity rating of each circuit breaker that is connected to each PV source circuit within the combiner box a. 10 amps b. 15 amps c. 35 amps d. 60 amps
b. 15 amps * see book for full explanation *
what is the largest grid tied array that can be load-side connected to a 100 amp rated service panel box currently connected to 100 amp service from the utility a. 2.4 kW b. 3.84 kW c. 4.8 kW d. the panel has already reached its rated capacity, so no PV array can be connected
b. 3.84 kW * see book for full explanation *
a homeowner in Phoenix, AZ has a daily load requirement of 9.6 kWh. she has opted to use micro inverters that will produce 250 W at STC. she has set the altitude at 25 degrees, giving her 6.54 hours of insolation. assuming she has selected a panel that will produce at least 250 W, and assuming her system is 95% efficient-how many solar panel are required to fully meet her load demand? a. 6 b. 7 c. 9 d. 11
b. 7 * see book for full explanation *
when adjusting the orientation of a solar panel up and down in relation to the horizon, this adjustment affects its a. azimuth b. altitude c. declination d. resistance
b. altitude
the main DC disconnect is required to include a label that contains the following information except a. open circuit voltage (Voc) b. array generating capacity (kW) c. maximum power voltage (Vmp) d. short circuit current (Isc)
b. array generating capacity (kW)
all grid tied inverters must a. be rated at no more than 48 volts DC b. be UL 1741 listed c. incorporate a modified sine wave output wave form d. be rated at 125% of the array's output as per the NEC
b. be UL 1741 listed
an AC disconnect should comply with all of the following EXCEPT a. isolate the PV system from the electric utility grid b. be located at least 10 feet away from the point where the PV system connects with the grid c. be externally operable d. be clearly marked "distributed generation disconnect switch"
b. be located at least 10 feet away from the point where the PV system connects with the grid
which of the following is NOT a widely available type of PV solar cell on the market today a. mono crystalline PV b. bicrystalline PV c. polycrystalline PV d. amorphous PV
b. bicrystalline PV
which of the following is NOT an advantage in selecting a lithium ion battery over a deep cycle lead acid battery a. higher energy density by weight b. easier to recycle c. more resistant to cold temperatures d. extended life cycle
b. easier to recycle
EMT conduit must be supported a. every 3 feet, except for buried conduit runs b. every 10 feet and within 3 feet of each box, fitting or cabinet c. every 4.5 feet and within 12 inches on each side of each box, fitting or cabinet d. at a distance not to exceed the take up subtracted from the stub height
b. every 10 feet and within 3 feet of each box, fitting or cabinet
which of the following is NOT relevant to DC circuits a. resistance b. hertz c. ohms law d. voltage drop
b. hertz
if the wire from a PV array is placed in a conduit and exposed to sunlight, the ampacity rating required for that wire must a. be adjusted by a 1.25 correction factor b. increase c. be adjusted if there are less than 4 conductors in the conduit d. not exceed 23 amps
b. increase
which of the following battery types have been known to spontaneously combust when a cell is damaged a. deep cycle lead acid b. lithium ion c. absorbed glass mat d. nickel cadmium
b. lithium ion
using declination map in figure 6-2, estimate the adjustment required to a magnetic compass, while sitting an. array in Denver, Colorado a. no adjustment is required b. orient the array 11 degrees east of magnetic south c. orient the array 7 degrees east of magnetic south d. orient the array 7 degrees west of magnetic south
b. orient the array 11 degrees east of magnetic south
a battery bank with a capacity of 600 Ah will a. provide 20 amps of power for 600 hours b. provide 20 amps of power for 15 hours to a 50% DOD c. provide 10 amps of power for 15 hours at 20% DOD d. provide 600 continuous amps over a 24 hour period
b. provide 20 amps of power for 15 hours to a 50% DOD * see book for full explanation *
when bending EMT conduit a. bends cannot extend beyond 90 degrees b. subtract the take up from the stub height c. no more than 360 degrees of bends are allowed in a single circuit d. ensure the bend is properly crimped
b. subtract the take up from the stub height
roof top mounting systems generally use top down mounting clamps because a. they are generally less expensive than bottom up mounting clamps b. there is usually very little room to work behind the panels on a roof top installation c. they are required by the NEC for residential roof top installations d. all of the above
b. there is usually very little room to work behind the panels on a roof top installation
which of the following is NOT and advantage of micro inverters over string inverters a. no string calculations are required b. they are easily accessible for repairs c. they are more efficient than string inverters d. they reduce aging panel mismatch
b. they are easily accessible for repairs
a disadvantage of slat water batteries is a. when overcharged they emit hydrogen gas b. they are very expensive compared to other alternatives c. when damaged they tend to explode d. they are made of toxic materials that are difficult to recycle
b. they are very expensive compared to other alternatives
it has been determined that a home requires a 6.5 kW array. the homeowner has purchased 26 solar world 250 W panels from her brother in law. at her location, the temp. extremes are -37 degrees celsius (coldest) and 43 degrees celsius (hottest). her string inverter has an operating input range of 100-550 Vdc. the solar panels have the following characteristics: Voc= 37.8 V Temp. coefficient (Voc)= .30%/degree Celsius Vmp= 31.1 V temp. Coefficient (Pmax)= .45%/degree Celsius what is the maximum number of panels in each string a. 8 b. 10 c. 12 d. 14
c. 12 * see book for full explanation *
a cabin sits on a mountaintop in North Carolina. the location has a latitude of 35 degrees north and 4.8 hours of insolation. the daily load requirement is 3 kWh. the designer has installed a 48 Vdc stand alone system that has been derated at 75%. the inverter is 95% efficient. the temp. extremes at this location are -37 degrees celsius (coldest) and 43 degrees celsius (hottest). the battery bank provides two days out autonomy and uses 6 volt, 250 Ah batteries to a 60% depth of discharge. how many batteries did the designer anticipate would be required? a. 1 b. 3 c. 8 d. 24
c. 8 * see book for full explanation *
which of the following equipment will likely NOT comply with the 2014 NEC requirement for "rapid shutdown" a. power optimizer b. micro inverter c. UL 1741 listed string inverter d. remote disconnect combiner box
c. UL 1741 listed string inverter
when an unintended pathway is created between a PV array and a grounded surface, this is known as a. grounding and bonding b. an arc fault c. a ground fault d. short circuit current
c. a ground fault
a two dimensional diagram representing the tracking of the sun over an entire year for a given latitude is referred to as a. an insolation map b. an I-V curve c. a sun chart d. all of the above
c. a sun chart
which of the following will likely NOT be required by the local building department prior to the installation of PV system a. an electrical permit b. a mechanical permit c. an interconnect agreement d. a license or certification
c. an interconnect agreement
a battery C-rating of C20 means a. at that rate of discharge a battery will be fully drained in 20 minutes b. at that rate of charging it will take 20 hours to full charge a battery bank c. at that rate of discharge it will take 20 hours to full drain the battery d. at the current rate of discharge, optimum capacity will be reached at a 20% DOD
c. at that rate of discharge it will take 20 hours to full drain the battery
which of the following inverter system comply with the NEX 2014 "rapid shutdown" provision a. bimodal inverters with MPPT b. multi-modal inverters with PWM c. fixed voltage inverters with power optimizers d. none of the above
c. fixed voltage inverters with power optimizers
a racking system that follows the pitch of the roof and is off set from the roof deck by four to 10 inches is referred to as a(n): a. flashed to deck racking system b. building integrated racking system c. flush to roof racking system d. flat roof racking system
c. flush to roof racking system
which ladder is rated to carry 250 pounds a. light duty, type III, red b. medium duty, type II, green c. heavy duty, type I, blue d. extra heavy duty, type IA, orange
c. heavy duty, type I, blue
the voltage drop of a system is too great. what can a system designer typically do to fix this problem a. increase the storage capacity of the battery bank b. incorporate a voltage diode into the system c. increase the size of the wires used d. increase the maximum power point tracking (MPPT) setting within your inverter
c. increase the size of the wires used
most PV arrays utilize _______ cooling system a. sun tracking b. solar thermal c. passive air d. hydraulic assisted
c. passive air
which of the following is NOT a factor in determining the size (in amp-hours) of a stand alone system's battery bank a. the daily system load requirements b. the nominal voltage of the system c. peak hours of sunlight (insolation) for the location d. depth of discharge (DOD) of the battery bank
c. peak hours of sunlight (insolation) for the location
a proper maintenance and trouble shooting regime should always begin with a. periodic commissioning b. periodic compliance c. periodic monitoring d. periodic equalization
c. periodic monitoring
which of the following is NOT an electrical test normally conducted during the commissioning process? a. polarity testing b. resistance testing c. reactance testing d. performance testing
c. reactance testing
rails on mounting systems should be oriented to a. attach to the perimeter of the panels b. run perpendicular to the short side of the panel c. run perpendicular to the long side of the panel d. run perpendicular to the long side when oriented in a landscape configuration, but along the short side when oriented in a portrait configuration
c. run perpendicular to the long side of the panel
which of the following is considered the maximum CURRENT a panel can produce under standard test conditions a. open circuit voltage (Voc) b. maximum power voltage (Vmp) c. short circuit current (Isc) d. maximum power currents (Imp)
c. short circuit current (Isc)
a number of solar panels connected in series is referred to as a(n) a. array b. bank c. string d. band
c. string
which of the following steps in the commissioning process will identify that the charge controller is properly charging the battery bank? a. visual inspection of the system b. verification of code compliance c. system functioning tests d. verification of array power and energy production
c. system functioning tests
a charge controller must be compatible with all the following EXCEPT a. the battery bank's nominal voltage b. the array's nominal voltage c. the inverter's power rating (in watts) d. the array's output rating (in watts)
c. the inverter's power rating (in watts)
which of the following is an example of a dead weight of the PV system a. the weight of an installer walking on the roof b. pressure from wind flowing over an array c. the shipping weight of the racking and panels d. the weight of the shingles and decking on the roof
c. the shipping weight of the racking and panels
the batteries in a stand alone system seem to fail prematurely. which of the following is likely NOT a cause of such a situation a. excessive loads b. poor temp. control c. too many batteries in series d. too many batteries in parallel
c. too many batteries in series
an array of 24 panels, each with an Isc of 8.35 amps, has been configured into 4 strings of 6 panels each. the wires from these strips are combined in a combiner box. what is the minimum ampacity rating required for the wire used in the PV output circuit a. 13.05 amps b. 33.4 amps c. 41.75 amps d. 52.19 amps
d. 52.19 amps * see book for full explanation *
the MAXIMUM DC nominal voltage a residential GRID TIED system in the U.S. can be configured to (by code) is: a. 12 volts b. 24 volts c. 50 volts d. 600 volts
d. 600 volts
you have configured a solar powered electric fence designed to operate 24 hours a day. your solar panel is rated at 12 nominal volts. when you test the fence, you find it is generating a 2000 volt electric shock. which of the following did you need to configure your system? a. PV panel, inverter, 12 Vdc battery bank, AC disconnect, DC voltage converter b. PV panel, charge controller, 12 Vdc battery bank, AC disconnect c. PV panel, charge controller, 6 Vdc battery bank, DC disconnect, combiner box, inverter d. PV panel, DC disconnect, charge controller, 12 Vdc battery bank, DC voltage converter
d. PV panel, DC disconnect, charge controller, 12 Vdc battery bank, DC voltage converter
when mounting a racking system on a rooftop, ensure that a. it is located at least 36 inches from the sides and ridge of the roof b. the mounting brackets are secured to the rafters c. the rails are mounted perpendicular to the run of the rafters d. all of the above
d. all of the above
when placing an array on a roof, which of the following should be considered a. the live weight b. the dead weight c. condition of the rafters d. all of the above
d. all of the above
when sizing a battery bank, its storage capacity is measured in a. discharge rate b. watts c. charging cycle d. amp-hours
d. amp-hours
using the sun chart in figure 6-10, determine the optimal angle of the array to capture the most energy from the sun on March 30th at 10am a. azimuth: solar south (180 degrees), altitude: latitude (48 degrees) b. azimuth: solar south (180 degrees), altitude: 65 degrees c. azimuth: solar south (180 degrees), altitude: 25 degrees d. azimuth: southeast (135 degrees), altitude: 45 degrees
d. azimuth: southeast (135 degrees), altitude: 45 degrees
________ provide a baseline performance record of how the system was functioning on the day it began operations a. operation and maintenance documents b. the plan view c. the electrical permit d. commissioning forms
d. commissioning forms
silicon works well as a material from which to construct solar cells because a. it is doped b. it is an n-type material c. it is an excellent conductor d. it is a semiconductor
d. it is a semiconductor
which of the following is NOT a factor that will affect the performance of a solar cell a. the band gap energy characteristics b. the internal load resistance c. the size of the cell d. its Ah capacity
d. its Ah capacity
when placing several rows of ground mounted panels, in order to avoid interior shading a. mount the panels using a landscape orientation b. make sure each row is set at least 9 feet apart c. adjust the azimuth to not less than 15 degrees off true south d. none of the above
d. none of the above
when placing the BOS of a PV system, ensure that a. they are facing as close to solar south as possible b. all cabinets and cases are rated for interior conditions c. they do not contain any overcurrent protection d. none of the above
d. none of the above
a PV system that uses batteries and is NOT connected to the local utility is referred to as a: a. grid tied system b. grid interactive system c. grid fall back system d. off grid system
d. off grid system
older change controllers used a thermostat type control known as a series controller. today most charge controllers use: a. parallel controllers b. inverters c. Mc4 connectors d. pulse width modulation (PWM)
d. pulse width modulation (PWM)
a load diverter a. reduces the system load demand when the array is not generating enough power b. redirects excess power to the grid for net metering through a grid-tied inverter c. reduces the load from the array so the battery bank does not overcharge d. redirects excess power from the array to a load dump, such as a hot water heater
d. redirects excess power from the array to a load dump, such as a hot water heater
which type of mounting system will increase the amount of time the panel directly faces the sun a. rooftop b. ground c. pole mounted d. sun tracking
d. sun tracking
in the U.S., rules regarding climbing safety are generally formed by: a. the international building code (IBC) b. the national electrical code (NEC) c. the American national standards institute (ANSI) d. the occupational safety and health administration (OSHA)
d. the occupational safety and health administration (OSHA)
nickel iron batteries are often used in mining operations because a. they can remain discharged for long periods of time b. they are very expensive compared to other alternatives c. when damaged they tend to explode d. they are extremely rugged and robust - can handle large amount of physical stress
d. they are extremely rugged and robust - can handle large amount of physical stress
which os preferred, landscape or portrait orientation a. landscape is preferred on ground mounted system, while portrait is preferred on installations b. landscape is preferred on rooftops built before 1970 to more evenly distribute the weight across more support rafters c. the preferred method is determined by local building officials d. this is largely determined by the racking system design
d. this is largely determined by the racking system design
which of the following represents the LARGEST diameter wire a. 0 AWG b. 2 AWG c. 6 AWG d. 12 AWG
a. 0 AWG
which of the following wire can carry the greatest current a. 0 AWG b. 2 AWG c. 6 AWG d. 12 AWG
a. 0 AWG
under standard test conditions (STC) for solar panels, the amount of sunlight hitting the panel (known as irradiance) is assumed to be ______ a. 1,000 watts per square meter b. 364 watts per square foot c. higher in cold weather than in warmer weather d. dependent upon the relative humidity
a. 1,000 watts per square meter
six solar panels are connected in series. each panel has a Vmp rating of 18 Vdc and an Imp rating of 8.33 amps. the output VOLTAGE of this string will be: a. 108 Vdc b. 108 Vac c. 18 Vdc d. 8.33 amps
a. 108 Vdc
Oscar is conducting a load analysis on a barn. there are three critical loads that must be serviced by the PV system. A water heater uses 1,700 Wh/day and runs for four hours each day. a milking machine uses 900 Wh/day and runs for three hours. a grain mixer uses 1,200 W when operating, but only operates for two hours, twice a week. assume the rate of energy used by all the machines is constant when running (no surges or cycles). what is the daily load demand if these three critical loads are the only loads in the barn? a. 3,286 Wh b. 2,600 Wh c. 3,800 Wh d. 543 Wh
a. 3,286 Wh *see textbook for full explanation*
solar panels are manufactured in accordance with ______ a. ANSI/UL 1703 b. STC c. PTC d. NEC
a. ANSI/UL 1703
Albert Einstein argued that light was made up of tiny packets of energy that moved like a wave. He called these packets of energy "lichtquant" or light quantum. This term later became known as: a. a photon b. photovoltaics c. a semi conductor d. an electron
a. a photon
a system that produces energy at or near the point where it will be used, and is generally owned by the customer (such as solar array or a generator) is referred to as a : a. distributed energy system b. disbursed energy system c. interconnected energy system d. net metered energy system
a. distributed energy system
electricity is generated when _________ move along conductive wires a. electrons b. photons c. neutrons d. protons
a. electrons
a point where the cost of electricity from a solar energy system is the same price as electricity purchased from the local electric company is known as a. grid parity b. the feed in tariff c. delightful d. the solar set aside
a. grid parity
a PV system that DOES NOT use batteries and IS connected to the local utility is referred to as a: a. grid tied system b. grid interactive system c. grid fall back system d. off grid system
a. grid tied system
the most common type of residential home PV system installed in developed countries today is the: a. grid tied system b. grid interactive system c. grid fall back system d. off grid system
a. grid tied system
cycles per second are referred to as: a. hertz b. ohms c. joules d. intensity
a. hertz
generally the first step in designing a PV system is to determine the _______ a. load requirements b. customer's budget c. cost of solar panels d. the size of the array
a. load requirements
the most power (measured in watts) a household might use any particular moment is referred to as the household's: a. maximum power draw b. continuous power rating c. daily load demand d. power surge rating
a. maximum power draw
NOCT stands for a. nominal operating call temperatures b. normal operating test conditions c. national official certified test d. normal observed conditional testing
a. nominal operating call temperatures
the highest voltage a panel can generate (under standard test conditions), with no load connected to it os referred to as the panel's _____ a. open circuit voltage b. nominal voltage c. short circuit voltage d. maximum power voltage
a. open circuit voltage
the eight foot long metal rod, commonly called the "ground rod" is more accurately referred to as: a. the grounding electrode b. the system ground c. the equipment ground d. the grounding conductor
a. the grounding electrode
the electricity consumed by all the lights and appliances in a structure is referred to as: a. the system load b. the grid fallback c. the irradiance of the site d. the net meter
a. the system load
Oscar is conducting a load analysis on a barn. there are three critical loads that must be serviced by the PV system. A water heater uses 1,700 Wh/day and runs for four hours each day. a milking machine uses 900 Wh/day and runs for three hours. a grain mixer uses 1,200 W when operating, but only operates for two hours, twice a week. assume the rate of energy used by all the machines is constant when running (no surges or cycles). assuming all the machines can be operated at the same times, what is the maximum power draw that must be accommodated? a. 3,800 W b. 1,925 W c. 1,200 W d. 1,025 W
b. 1,925 W * see textbook for full explanation *
a 400 foot cable run, using #10 AWG stranded copper wire on a circuit designed to carry 8.3 amps and 48 volts of electricity voltage drop = 8.23 V what percentage of the power from the circuit will be lost due to voltage drop? a. 21.44% b. 17.15% c. 8.78% d. 2.58%
b. 17.15% * see book for full explanation *
60 watt-hours is equal to: a. 6 kilowatts consumed over a 10 hour period of time b. 240 watts consumed for 15 minutes c. 60 watts consumed at a constant rate for a 24 hour period d. 120 watts consumed for 2 hours
b. 240 watts consumed for 15 minutes * see textbook for full explanation *
a #4 AWG TW copper conductor has an ampacity rating of ( we have to look at table 5-1 ) a. 35 amps b. 70 amps c. 85 amps d. 95 amps
b. 70 amps
what is the voltage drop of a 400 foot cable run, using #10 AWG stranded copper wire on a circuit designed to carry 8.3 amps and 48 volts of electricity a. 10.29 V b. 8.23 V c. 4.216 V d. 1.24 V
b. 8.23 V * see book for full explanation *
converting the energy of the sun from light to electricity is known as a. solar thermal b. photovoltaics c. polycrystalline d. megawatts
b. Photovoltaics
watts equal a. volts minus resistance b. amps times volts c. volts divided by amps d. resistance plus amps divided by volts
b. amps times volts
in 1953, three scientists from _______ determined that silicon performed well as a component within photovoltaic cells a. germany b. bell labs c. NASA d. california
b. bell labs
at night, or if the panels are shaded, the energy stored in the batteries can flow backwards, from the battery to the panel. to prevent this from happening, manufacturers place _________ within the junction box on the solar panel a. bypass diode b. blocking diodes c. rectifying diodes d. amplifying diodes
b. blocking diodes
a _______ is necessary for electrons to flow from the negatively charged portion of the solar panel to the positively charged portion of the panel a. permit b. circuit c. diode d. charge controller
b. circuit
a PV system that uses batteries and IS connected to the local utility is referred to as a : a. grid tied system b. grid interactive system c. grid fall back system d. off grid system
b. grid interactive system
when selecting the appropriate wire gauge, which of the following is of greatest concern a. the price b. its ampacity rating c. its resistance rating d. its voltage rating
b. its ampacity rating
the cel temperature of a panel is measured and found to be 30 degrees celsius. this panel will produce _________ energy compared to a similar panel measured at 25 degrees celsius a. more b. less c. the same d. twice the
b. less
the ______ is the rating on a solar panel that indicates the voltage a panel will produce when generating its rated power when measured under standard test conditions a. maximum power (Pmax) b. maximum power voltage (Vmp) c. open circuit voltage (Voc) d. short circuit voltage (Isc)
b. maximum power voltage (Vmp)
__________ employ multiple layers of thin films. each layer can more efficiently absorb light within a very narrow band. in combination, these cells can more efficiently absorb light over a wider portion of the electromagnet spectrum a. mono crystalline cells b. multi junction pv cells c. Polycrystalline cells d. thin-film
b. multi junction pv cells
commonly a solar panel used in a stand alone PV system will be described as a 12 volt or 24 volt panel. when referenced in this manner, we are speaking of the panel's _________ a. open circuit voltage b. nominal voltage c. short circuit voltage d. maximum power voltage
b. nominal voltage
as the temperature of the PV array rises above 25 degrees C, the panel will: a. produce more power b. produce less power c. temp. does not affect the ability of a panel to produce power d. automatically disconnect at 35 degrees C
b. produce less power
solar cells rely on a materials such as silicon that allow some, but not all of the energy to flow through them. these materials are known as: a. p-n junction compounds b. semi-conductors c. doped conductors d. a diode
b. semi-conductors
the ratings noted on most solar panels are the result of laboratory testing using ________ a. generally accepted accounting principles (GAAP) b. standard test conditions (STC) c. underwriters laboratories (UL) d. American national standards institute (ANSI)
b. standard test conditions (STC)
net metering laws require a. that utilities provide meters free of charge to all distributed energy system owners b. that utilities allow solar energy system owners to sell excess energy to the utility for the same price they pay for energy purchased from the utility c. that utilities provide a certain amount of energy (varies from state to state) from Renewable sources such as wind, solar or hydro d. that utilities have "first option" on all power generated through distributed energy systems owned by their customers, meaning that the owner must sell to the utility prior to making the energy available to any other potential customers
b. that utilities allow solar energy system owners to sell excess energy to the utility for the same price they pay for energy purchased from the utility
when seeking to decrease the effect of voltage drop on a circuit, which of the following is NOT an effective solution a. shorten the length of the circuit b. use a smaller (in diameter) wire size c. increase the voltage of the system d. select a wire with better conducting properties
b. use a smaller (in diameter) wire size
the loss of an electrical signal over distance as it travels along a conductor due to resistance is referred to as: a. its root mean square b. voltage drop c. the ampacity rating d. a ground and bonding system
b. voltage drop
when there is an imbalance between positive and negative charges (such as the terminals of a battery) there is a difference in electrical potential. This difference is measured in ______ a. watts b. volts c. amps d. ohms
b. volts
Oscar is conducting a load analysis on a barn. there are three critical loads that must be serviced by the PV system. A water heater uses 1,700 Wh/day and runs for four hours each day. a milking machine uses 900 Wh/day and runs for three hours. a grain mixer uses 1,200 W when operating, but only operates for two hours, twice a week. assume the rate of energy used by all the machines is constant when running (no surges or cycles). assuming only one of the machines can be operated at a time, what is the maximum power draw that must be accommodated? a. 3,800 W b. 1,925 W c. 1,200 W d. 1,025 W
c. 1,200 W * see textbook for full explanation *
sally is conducting a load analysis for a small business, a bakery. their dough mixer runs for 3 hours, two times a week. each time it is operated, it consumes 1,400 Wh during that three hour period. how much would you calculate is the mixer's contribution to the DAILY load requirements of the business a. 2.8 kWh b. 467 Wh c. 400 Wh d. 1.4 kWh
c. 400 Wh *see book for full explanation if you want*
who is largely credited with first discovering the photovoltaic effect, which later led to the development of photovoltaic cells? a. Albert Einstein b. Alexander Graham Bell c. Antoine-Cesar Becquerel d. Charles Fritts
c. Antoine-Cesar Becquerel
which of the following will likely create the greatest REDUCTION in a PV module's output a. measured cell temperature of below zero degrees celsius b. the age of the panel is 10 years old c. Approximately one-quarter of the panel is covered in snow d. the 200 W panel is half the size of another 200 W panel
c. Approximately one-quarter of the panel is covered in snow
one main difference between STC and PTC (PV USA test conditions) is that: a. PTC is only used in the USA b. PTC does not concern itself with atmospheric pressure c. PTC addresses wind speed while STC does not d. PTC measures in imperial units (U.S. based) rather than metric
c. PTC addresses wind speed while STC does not
______ are constructed by pouring molten silicon into bars, and then slicing wafers from the hardened material. this type of PV cell is less expensive to produce, but is also a bit less efficient a. mono crystalline cells b. multi junction pv cells c. Polycrystalline cells d. thin-film
c. Polycrystalline cells
which of the following is the smallest, most basic component? a. a solar photovoltaic array b. a solar photovoltaic module c. a solar photovoltaic cell d. a solar photovoltaic panel
c. a solar photovoltaic cell
the amount of flow or current is measured in ______ a. watts b. volts c. amps d. ohms
c. amps
the amount of energy (measured in watt-hours) a household might use in an average day is known as the household's: a. maximum power draw b. continuous power rating c. daily load demand d. power surge rating
c. daily load demand
a distributed energy system that incorporates both solar (PV) and wind power would be an example of a: a. grid tied system b. grid fallback system c. hybrid system d. redundant system
c. hybrid system
attaching a photovoltaic system to the grid is known as: a. Commissioning b. net-metering c. interconnecting d. a solar set aside
c. interconnecting
the ______ is the rating on a solar panel that indicates the theoretical maximum voltage a panel will produce measured under standard test conditions a. maximum power (Pmax) b. maximum power voltage (Vmp) c. open circuit voltage (Voc) d. short circuit voltage (Isc)
c. open circuit voltage (Voc)
what technology used within inverters is generally used today to most closely mimic utility power, and avoids problems with sensitive electronic devices a. square wave b. modified sine wave c. pure sine wave d. net-metering
c. pure sine wave
more people are killed each year in the U.S. working on ________ systems than any other type of electrical system a. photovoltaic electrical b. high voltage electrical c. regular household electrical d. hybrid electrical
c. regular household electrical
when measuring the terminals of a blown fuse with a multimeter set to perform a continuity test, the reading will show: a. resistance= 0 b. voltage=0 c. resistance= 1 (or infinite) d. amps=1 (or infinite)
c. resistance= 1 (or infinite)
the document that details industry best practices from a SAFETY perspective in the U.S. is: a. the American national standards Institute (ANSI) b. underwriters laboratories (UL) c. the national electric code (NEC) d. the electronic technicians association International (ETA-I)
c. the national electric code (NEC)
which of the following is NOT an advantage of a system that includes micro inverters a. can use mismatched panels b. the array can easily be explained over time c. the panels will not need to be replaced as often d. the effect of saving is reduced
c. the panels will not need to be replaced as often
when a number of solar panels are connected in parallel a. the voltage and amps remain the same b. the voltage increases but the amps remain the same c. the voltage remains the same, but the amps increase d. both voltage and amps increase
c. the voltage remains the same, but the amps increase
electricity is generally purchased in units referred to as _______ a. watts (W) b. kilowatts per hour (kW/h) c. watt hours (Wh) d. kilo amps (kA)
c. watt hours (Wh)
in space (at the outside edge of the Earth's atmosphere), the energy of the sun (irradiance) will measure about a. 1.5 atmospheres b. 1.0 atmospheres c. 0.0 atmospheres d. 1,300 watts/m^3
d. 1,300 watts/m^3
six solar panels are connected in series. each panel has a Vmp rating of 18 Vdc and an Imp rating of 8.33 amps. the output CURRENT of this string will be a. 108 Vdc b. 108 Vac c. 18 Vdc d. 8.33 amps
d. 8.33 amps
according to government statistics, in 2015 the average U.S. home consumed about _______ of electricity per month a. 850 Wh b. 460 kWh c. 2675 kWh d. 900 kWh
d. 900 kWh
today most solar panel incorporate a. Mc1 connectors b. Mc2 connectors c. Mc3 connectors d. Mc4 connectors
d. Mc4 connectors
the NEC document is also referred to as: a. industry best practices b. the law of the land c. ugly's reference guide d. NFPA 70
d. NFPA 70
how much a panel's energy production increases or decreases for every degree Celsius the cell temperature varies from STC is known as the panel's : a. IV curve b. open circuit voltage c. nominal operating cell temperature d. Temperature coefficient
d. Temperature coefficient
which of the following wire insulation is rated for outdoor wet conditions a. THHN b. THWN c. NEC d. USE-2
d. USE-2
bare wire or green insulation will always indicate the wire is part of ___ a. a photovoltaic system b. a hybrid system c. a DC system d. a ground and bonding system
d. a ground and bonding system
which of the following is NOT a safety recommendation when working with electric wires a. always check and test exposed wires, ensuring there is no current present before handling b. wear safety goggles when working with electrical systems c. always use protective gloves and wear insulated shoes when working on electrical systems d. always wear respirator when working with exposed wiring
d. always wear respirator when working with exposed wiring
when selecting a stand alone inverter, all the following specifications are important EXCEPT: a. system nominal voltage rating b. power rating c. conversion efficiency d. anti-islanding feature
d. anti-islanding feature
standard testing conditions also assume two other conditions (other than irradiance) be present. these include: a. wind speeds of less than 5 mph, and ambient air temperature of 77 degrees celsius b. wind speeds greater than 5 mpg, and ambient temperature of 25 degrees celsius c. atmospheric pressure equal to 1.5, and cell temperatures of 77 degrees celsius d. atmospheric pressure equal to 1.5, and cell temperatures of 25 degrees celsius
d. atmospheric pressure equal to 1.5, and cell temperatures of 25 degrees celsius
the energy from a photon striking a solar panel must be at least as much as is required to "knock" an electron across the space where the top wafer of a solar cell and the bottom wafer meet. Silicon has a relatively low ______ energy level (1.1 electron volts - or 1.1 eV) a. transference zone b. convergence zone c. PV junction d. bandgap
d. bandgap
the system designed to eliminate all unwanted current from non-current carrying metal components is referred to as _________ a. net metering b. a blocking diode c. transient flow resistance d. bonding and grounding
d. bonding and grounding
when a circuit is closed: a. it is disconnected from the utility grid b. power cannot flow through it c. a fuse has blown or a circuit breaker has tripped d. electrons can flow through it
d. electrons can flow through it
at some point along the diagram, the panel will produce the most power (watts). but this point will not be at maximum voltage (the VOC) nor will it be at maximum current (Isc). this point alone the curve when the most power is produced by the panel is referred to as its ________ a. nexus b. matrix c. p-n junction d. maximum power point
d. maximum power point
the photovoltaic effect: a. refers to changes our society has experienced as more and more people adopt solar electric systems b. occurs when heat is released as light photons strike a solid surface, such as the surface of a PV panel c. refers to the unusual characteristic of photons where they can behave as a particle as well as a wave d. occurs when the light from the sun is converted into electricity
d. occurs when the light from the sun is converted into electricity
when referencing the resistance characteristics of various conductors or wires, the NEC measures in the following units: a. volts per watt b. amps per volt c. watts per square meter d. ohms per 1,000 feet
d. ohms per 1,000 feet
what emerging PV technology results in transparent or many colored cells, making them ideal for sola windows or other building integrated applications a. multi junction thin film b. flat plate modules c. two dimensional solar cells d. perovskite solar cells
d. perovskite solar cells
the most cost effective way of reducing the cost of a photovoltaic system in a residential setting is: a. to increase the number of hours of insolation at the site b. to increase the size of the array by adding additional panels c. to connect the system to the electrical grid d. reduce the load demand through energy efficiencies
d. reduce the load demand through energy efficiencies
owners of solar energy systems can often make additional money by selling __________ to utilities, who must produce a certain amount of their power from renewable sources according to state's renewable portfolio standard a. renewable set asides b. easement reduction credits c. utility portfolio standards certificates d. renewable energy certificates
d. renewable energy certificates
when a state determines that a certain amount of energy must be generated through a renewable source, this is referred to as state's: a. solar renewable energy certificate (SREC) b. renewable energy manifesto (REM) c. renewable energy certificate (REC) d. renewable portfolio standard (RPS)
d. renewable portfolio standard (RPS)
an SREC is a: a. special regional energy commission b. silicon resistant emitting crystal c. sustainable renewable energy concept d. solar renewable energy certificate
d. solar renewable energy certificate
which of the following is NOT a factor that affects how much power a solar panel will produce a. the size of the panel b. the reflective coating on the panel c. the air temperature d. the relative humidity
d. the relative humidity
one advantage of _______ technology (also referred to as amorphous, meaning "without shape") is that they are flexible and can be more easily integrated into the building design - such as solar shingles a. mono crystalline cells b. multi junction pv cells c. Polycrystalline cells d. thin-film
d. thin-film