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WorksheetsSOLAR PRACTICE TEST
Total questions: 115
Worksheet time: 58mins
OSHA requires that eye protection used in the workplace meet which of the following standards?
UL Section 690.5
IEEE 1703
IEC 1108-14
ANSI Z87.1
High voltage will trip a circuit breaker...
voltage is not what trips a breaker
when it is over 600 VDC
sometimes at the apex of a sine wave
when it is AC only
The 120% rule means...
your circuit breakers should be 120% derated for ampacity
your parallel sources of AC power can never exceed the breaker box rating
The sum of the solar breaker and the main breaker must be 120% less than the busbar rating
the maximum rating for the solar breaker is 120% times the breaker panel minus the rating for the main circuit breaker
Flat-plate collectors receive the following primary types of total global solar radiation...
Albedo
Direct & reflected
Diffused & absorbed
Direct & diffused
Blocking diodes main function is...
prevent controller from shorting battery
bank
to prevent reverse current flow
to pass current around PV cells or
modules
minimize power output loss
Which of the following statements is true regarding temperature effects on PV modules?
Lower temp increases I & increases V
Higher temp increases V & increases
Lower temp increases V & decreases I
Higher temp decreases V & decreases P
An equinox is when...
solar declination is at 23.5
solar declination equals the latitude
Hours of daylight & nigh are the same
the daytime is the longest
A 48-volt, stand-alone system has a daily requirement of 2500 Wh. This home requires 4-days of autonomy at 80% DOD. What is the total battery capacity requirement?
444 Ah
260.4 Ah
44.4 Ah
333 Ah
It is necessary to know the lowest possible temperature at a site when sizing a PV system to prevent...
under-current
over-current
over-voltage
under-voltage
Irradiance is a measure of solar power per unit of....
time
area
heat
distance
Which of the following battery types require no electrolyte maintenance...
Gel cell
VRLA
AGM
All of these
For a PV system in a remote village in Pakistan, one would typically choose a...
stand-alone inverter
synchronous grid-tied inverter
synchronous grid-tied with battery back-up
Fronius AGM inverter
Which of the following devices does the NEC require to be a part of PV systems mounted on residential dwellings?
An accessible source circuit combiner
box
A stand-off mount for the modules
A ground-fault protection device
An utility interconnection
What tool measures irradiance?
Solmetric Suneye
Cat II multimeter
Amp clamp
Pyranometer
A hydrometer reading of 1.30 usually indicates
a VRLA battery
a fully discharged battery
a fully charged battery
a primary battery
A wire in a higher temperature location...
can carry more current
can carry less current
can carry less voltage
can carry more voltage
The first step in system checkout after completing the installation is...
visually check the entire system
close all disconnects
test open-circuit voltage
install the source-circuit fuses
If you combine solar and a diesel generator in an off-grid system, it is a...
Sinusoidal system
Hybrid system
Bimodal system
Interactive system
In the event that the utility voltage is lost in a utility-interactive system, the inverter should...
no longer take DC power from the array
not supply power to the battery bank
continue to function normally
not supply power to the distribution
panel
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...
homeowner is using too much power
array was struck by lightning
PV breaker in distribution panel is
tripped
dust and dirt on the array
The NEC definition of PV source circuit is...
wires from combiner or junction box to inverter
wires from PV array to combiner box
all BOS wiring in a PV source system
wires between modules in a string but not to combiner or junction box
Ladders should extend above the structure on which it is used by...
3 ft.
2 ft.
4 ft.
the amount needed
The continuous total current load on system wiring is determined to be 60A. Except for the source circuit, the wiring, disconnects, fuses, and circuit breakers should be sized...
for 60A
for 48A
depending on system voltage
for 75A
In the Northern hemisphere, which tilt angle maximizes power in the winter?
90°
latitude - 15°
local latitude angle
latitude + 15°
Step-down transformers…
decrease voltage & current
increase voltage & decrease current
increase voltage & current
decrease voltage & increase current
Diodes act as which type of mechanical valve?
Check valve
Probe valve
Butterfly valve
Pressure valve
Wire ampacity is based on...
the voltage that a conductor can carry without exceeding its temperature rating
battery capacity
the number of modules that are used in series in a system
the number of parallel module strings
that are used in a system
If the maximum AC output rating of an inverter with 120VAC output is 2200W, the rating of the circuit breaker at the utility point-of-connection that should be used is...
20 A
12.5 A
25 A
18 A
PV module nameplates must contain…
Minimum system voltage
Minimum system current
PV cell material
Maximum power
Equinox...
is the same everywhere in the world at the same time.
is always on the 21st
means the sun is directly overhead at
the tropic of Capricorn.
happens once a year on leap years
Compass bearings designate South as...
90°
180°
0°
the same as azimuth angles
Lead-acid battery outgassing creates...
hydrogen and oxygen
AGM battery gas
electrolyte gas
sulfuric acid gas
A 300 Ah battery will deliver _____ for ______ hours before being considered fully discharged.
1A for 300 hrs.
all of these are correct
2A for 150 hrs.
300A for 1 hr.
The NEC article dedicated to PV is...
690
360 when using compass readings
690 mostly but some in 250
720
In a PV system, the purpose of grounding is to...
draw lightning away from components
permit current to flow in branch
circuits only
provide a means to disconnect & isolate all source circuits
prevent unwanted currents from flowing through the system
Which conductor has the highest resistance?
14 AWG
8 AWG
24 AWG
0000 AWG
For a stand-alone system with a load current of 50A and a charging current of 65A, the battery disconnect and wires should be sized to carry...
82A
78A
A maximum system voltage of 600V
63 A
The purpose of the ground-fault protection device in a PV system is to...
reduce degradation of structural supports from rapid electrolysis
reduce the probability of electrical shock to service personnel
reduce losses of the PV output energy to ground
reduce the possibility of fire from an arcing fault to ground
An insolation measurement takes into account these factors:
solar power, unit area
solar power, time, area, location
solar energy, unit area,
solar efficiency, unit area
A series string of 6 panels producing 42V each at 9A with an insolation of 5.7 hrs. will produce...
22.93 kWh
288 watts
12.93 kWh
1.7 kWh
A roof-mounted racking system transfer forces to the roof via the…
Module clamps
Flashing
Rails
Structural attachments
At night, the power for a grid-tied inverter comes from the…
Utility
PV array
Battery bank
Charge controller
Hydrometers measure...
battery lead content
electrolyte to determine battery charge
voltage to determine battery charge
Current to determine battery charge
Lag screw allowable withdrawal load is determined by...
length of the lag screw X 120%
Diameter,length of lag screw, and type of wood
the material the lag screw is made of
Number of threads in the lag screw
All of the following reduce or enhance solar irradiation received at a particular location except:
altitude
ozone
earth’s position in relation to the sun
module efficiency
After analyzing a particular system design that utilized 10 AWG copper conductors, an engineer calculated the voltage drop to be not acceptable. To remedy the problem, it was suggested that the system...
use 12 AWG aluminum conductors
use 12 AWG copper conductors
use 8 AWG copper conductors
array strings be reduced with less panels in series
Assume a 225-A breaker box has a 225-A main breaker in it. The maximum back feed breaker that can be installed is...
36 A
45 A
20 A
56 A
Irradiance is...
measured in watts
irradiation multiplied by time
measured in sun-hours per day
measured in watts per square meter
Where is the GFCI located in a PV system?
in the inverter
between the DC disconnect & the inverter
in the charge controller only
between the inverter & the AC disconnect
The hydraulic analogy of voltage is…
flow
pressure
density
specific gravity
Assuming the same PV system at the same temperature conditions, more power would be provided at…
sea level
10,000-ft. elevation
conductor resistance charts
conductor material & cross-sectional area
Net metering allows a residential home with a PV installation to…
receive credit for surplus energy
monitor their PV system on the Internet
only pay for the energy their PV system produces
network their system to the utility company
Designers typically try to design a system with a voltage drop of _____ or less.
Depends on the ruling by the NEC
2%
5%
Depends on how much they can get away with
Which curve best represents the lowest temperature?
curve “a”
curve “b”
curve “c”
None of these
Using the sun-path chart above, the maximum annual sun altitude between the hours of 9 a.m and 3 p.m sun time is closest to...
about 20°
about 30°
about 40°
about 85°
The continuous total current load on system wiring is determined to be 60A. The wiring, disconnects, fuses, and circuit breakers should be sized...
for 60A
for 48A
Depending on system voltage
for 75A
In the Northern hemisphere, which tilt angle maximizes power in the winter?
90°
latitude - 15°
local latitude angle
latitude + 15°
The width of the working space in front of an inverter that is 24” wide must be at least...
42"
24"
30"
36"
What is the best practice when troubleshooting a PV string that is not supplying current?
Turn off inverter & disconnect bad string
Disconnect bad string then turn off inverter
Short the bad string then turn off inverter
Turn off the inverter then short all other strings
Step-down transformers…
decrease voltage & current
increase voltage & decrease current
increase voltage & current
decrease voltage & increase current
Diodes act as which type of mechanical valve?
Check valve
Probe valve
Butterfly valve
Pressure valve
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?
Any type of nickel-cadmium
Nickel-iron acid
Flooded lead-acid
Valve-regulated lead-acid
Wire ampacity is based on...
the voltage that a conductor can carry without exceeding its temperature rating
battery capacity
the number of modules that are used in series in a system
the number of parallel module strings that are used in a system
If the maximum AC output rating of an inverter with 120VAC output is 2200W, the rating of the circuit breaker at the utility point-of-connection should be...
20A
12.5A
25A
18A
A 2500W inverter with an input voltage of 22V to 32V has an efficiency of 98% at full output. This means the maximum inverter output current at full rating will be closest to...
80
116
111
77
PV module nameplates must contain…
Minimum system voltage
CEC output rating
PV cell material
Maximum power
Equinox...
is the same everywhere in the world at the same time.
is always on the 21st.
means the sun is directly overhead at the tropic of Capricorn.
happens once a year on leap years
Compass bearings designate South as...
90°
180°
0°
the same as azimuth angles
Lead-acid battery outgassing creates...
hydrogen and oxygen
AGM battery gas
electrolytic gas
sulfuric gas
A 300 Ah battery will deliver _____ for ______ hours before being considered fully discharged.
1A for 300 hrs.
2A for 150 hrs.
300A for 1 hr.
all of these are correct
Inter-row spacing is determined by...
height of the panels at solar noon
sun angle & module voltage
sun angle & rack angle
rack manufacturer specifications
The most common inverters in use today are...
square wave inverters with very low harmonic distortion
modified square wave inverters
pulse-width modulation sine wave inverters
frequency-regulated stand-alone inverters
The NEC article dedicated to PV only is...
690
360
690 mostly but some in 250
720
In a PV system, the purpose of grounding is to...
draw lightning away from components
permit current to flow in branch circuits only
provide a means to disconnect & isolate all source circuits
prevent unwanted currents from flowing through the system
Which conductor has the highest resistance?
AWG 14
AWG 8
AWG 24
AWG 0000
According to OSHA regulations, to protect workers, toeboards shall be erected along the edge of platforms...
more than 6 feet above a lower level.
more than 12 feet above a lower level.
more than 10 feet above a lower level.
as needed.
OSHA requires guardrails to be...
used when working 6’ or more above the ground
42” high with at least 1 middle rail about halfway between the working surface & the top rail
42” high with at least 1 middle rail about halfway between the working surface & the top rail & must have a toeboard
36” high with at least 1 middle rail about halfway between the working surface & the top rail
A typical efficiency rating for a 5 kW inverter is...
dependent on the module array tilt
typically in the high 90’s percent
highest when operated past a certain output
95%
The magnetic declination of San Francisco is 15°. At what compass reading would true North be?
-15°
15°
South in San Francisco is always at 180°
165°
90° C rated wire...
has the same ampacity for all temperatures under 90°C
is not used in PV systems
is wire that should never get hotter than
90° C if you did everything right
is always black
A stand-alone inverter’s power output rating limits the size of the…
Utility service
System loads
Battery bank
PV array
For a stand-alone system with a load current of 50A and a charging current of 65A, the battery disconnect and wires should be sized to carry...
82 A
78 A
A maximum system voltage of 600V
63 A
The purpose of the ground-fault protection device in a PV system is to...
reduce degradation of structural supports from rapid electrolysis
reduce the probability of electrical shock to service personnel
reduce losses of the PV output energy to ground
reduce the possibility of fire from an arcing fault to ground
6 months after commissioning a system, a homeowner discovers the system is suddenly only 76 % efficient. The most likely cause for this is...
Voltage drop due to long cabling
distance
Grid brown-out condition
Damage to a conductor by a rodent
Design flaws in initial system
Captive electrolyte batteries are often referred to as...
AGM batteries
NiCad batteries
Stationary batteries
SLI batteries
To connect a PV system to the supply-side of a home, the connection is made between the…
Power pole & utility meter
Utility meter & AC service panel
AC service panel & main breaker
Subpanel & AC service panel
Everything else being equal, if you increase the total system voltage...
you have to increase the wire size
you should increase the amperage by 120%
you increase the voltage drop percentage
you decrease the voltage drop percentage
An insolation measurement takes into account these factors:
solar power, unit area
solar power, time, area
solar energy, unit area
solar efficiency, unit area
A series string of 6 panels producing 42V each at 9A with an insolation of 5.7 hrs. will produce...
22.93 kWh
288 watts
12.93 kWh
1.7 kWh
A PV array with 4 series strings, each outputting 350VDC @ 8A is paralled in a fused combiner box.
Those fuses should be rated at…
12.5 A
8 A
6.25 A
350 VDC
A roof-mounted racking system transfer forces to the roof via the…
Module clamps
Flashing
Rails
Structural attachments
A 3000W inverter is used to supply a 120 VAC load of 2600W. This means that the ampacity of the wire at the inverter output must be rated for at least...
27A
25A
32A
22A
The NEC definition of an interactive PV system is...
a PV system in series or parallel with the grid
a PV system that you can monitor and adjust the MPPT over the Internet
a PV system in parallel to the grid
a PV system in series with the grid
Before applying PV power to either an inverter, a charge controller, batteries, or a load, one should first...
install the source circuit fuses
check the polarity of the PV output circuit
call the electrical inspector
close all disconnects
Solar noon is....
always at 12:00 in the Northern hemisphere
when the sun reaches noon.
when the sun reaches zenith at a given location during a solstice
when the sun reaches a meridian at a given location & highest position in the sky.
What is the solar declination at solar noon at the Tropic of Cancer on June 21st?
90°
0°
180°
23.5°
The primary power for a grid-tied inverter comes from the…
Utility
PV array
Battery bank
Charge controller
Hydrometers measure...
battery lead content
electrolyte specific gravity to determine battery charge
voltage
Current
Lag screw allowable withdrawal load is measured by...
Width of lag screw
length of the lag screw
tensile strength necessary to forcibly remove the lag screw
Number of threads in the lag screw
All of the following reduce or enhance solar irradiation received at a particular location except:
altitude
ozone
earth’s position in relation to the sun
module efficiency
For an AC-coupled PV system, one would need a grid-interactive inverter and also a…
Diesel generator
Battery-based inverter
Charge controller
Power optimizer
After analyzing a particular system design that utilized 10 AWG copper conductors, an engineer calculated the voltage drop to be not acceptable. To remedy the problem, it was suggested that the system...
use 12 AWG aluminum conductors
use 12 AWG copper conductors
use 8 AWG copper conductors
array strings be reduced
Assume a 225-A, 42-position, single-phase, 3-wire main distribution panel fed by a 225-A main breaker is used in a dwelling unit. The maximum inverter output current that can be fed to this panel is...
36 A
45 A
20 A
56 A
Irradiance is...
irradiation multiplied by time
measured in sun-hours per day
measured in watts per square meter
measured in watts
Before commissioning a system, what would one measure to verify correct series wiring?
Resistance
Voltage
Irradiance
Amperage
On a particular PV system with an operating voltage of 350VDC and 20A, the distance from the combiner box to an inverter is 65 feet. The system design calls for using 14 AWG stranded THWN which has a resistance of 3.14 ohms per k-ft. What is the voltage drop percentage?
8.16V
2.3%
4.08V
1.1%
Where is the GFCI located in a PV system?
in the inverter
between the DC disconnect & the inverter
in the charge controller only
between the inverter & the AC disconnect
The hydraulic analogy of voltage is…
flow
pressure
density
volume
A PV system in Connecticut has 4 days of consecutive & consistently lower-than-normal irradiance levels. The module temperature is remotely monitored and appears to be far below normal levels.
The likely cause is…
the system pyranometer is bad
there is excess cloud coverage
there is snow deposited on the modules
the modules cannot handle the system voltage
Assuming the same PV system at the same temperature conditions, more power would be provided at…
sea level
10,000-ft. elevation
a coastal area
an inland area
Wire ampacity is determined from…
the molecular structure of copper
the amount of system voltage
c. conductor resistance charts
d. conductor material & cross-sectional area
According to the NEC, a charge controller is required if the maximum charging current multiplied by 1-hour is more than…
8% of the rated battery bank capacity expressed in Ah
3% of the rated battery bank capacity expressed in Ah
5% of the rated battery bank capacity expressed in Ah
1% of the rated battery bank capacity expressed in Ah
Net metering allows a residential home with a PV installation to…
receive credit for surplus energy
monitor their PV system on the Internet
only pay for the energy their PV system produces
network their system to the utility company
In order to maintain a 2% or less voltage drop in designing a PV system, the following factors are all
factors except…
conductor size
combiner-to-inverter distance
total system current
back-feed breaker size
A stand-alone system is connected to a 1 HP pump that runs 10% of the time and a 20W light that is on 100% of the time.
How much energy is used per month?
54Wh
68kW
68kWh
.063 MWh
