NABCEP TEST PREP QUESTIONS &
ANSWERS(RATED A+)
What is the most common PV system configuration in North America? - ANSWERNet-
metered grid-direct system
What happens to a grid direct system when the power goes down? - ANSWERThe
inverter is designed/required per UL and IEEE standards to shut off instantly. No grid
power, no solar power.
What terminals are connected in a series connection/PV source circuit? -
ANSWERPositive to Negative
In a series string what happens to the current and voltage? - ANSWERCurrent remains
the same, and voltage is additive
According to the NEC, what is the official name of a series string? - ANSWERPV
Source Circuit
After making a series string, what is done with the remaining terminals? - ANSWERThe
positive on one module, and the negative on the other become the "homerruns" or leads
What tool do you use to ensure your series connections are wired properly? -
ANSWERDigital Multimeter
How can you tell if all panels are working in a series string? - ANSWERThe voltage
should equal the open circuit voltage of all panels added together.
How does the power compare when if you were to wire the same two panels in series
then in parallel? - ANSWERThey would be the same
How do you wire modules in parallel? - ANSWERThe like terminals are connected
together... + to + and - to -
When modules are wired in parallel, what happens to the voltage? - ANSWERIt remains
the same
When multiple modules are wired in parallel at the combiner box, what is the output
wiring considered? - ANSWERPV Output Circuit
What tool is used to measure cell temperature? - ANSWERA temperature gun
How does irradiance impact voltage? - ANSWERIt has a very small impact
, What happens to the current as the irradiance increases? - ANSWERThe current
increases
What effect does irradiance have on current? - ANSWERAs one goes up, the other
goes up
At what point does irradiance start to have an effect on voltage? - ANSWER500 w/m^2
and below you may begin to notice 5-10% below what you would expect based on the
cell temperature at the time
What tool is used to measure irradiance? - ANSWERPyranometer
If my rated Imp of a module is 8 Amps, and my irradiance is 500 W/m^2 what would be
my expected current reading? - ANSWER4 Amps
What is the solar azimuth angle? - ANSWERThe position of the sun relative to North
What is the solar altitude angle? - ANSWERThe sun's position in degrees above the
horizon.
What is the tilt angle? - ANSWERThe degrees from flat that an array is angled
What is solar noon - ANSWERthe time of the day when the sun is at its highest point in
the sky
What may happen if the array voltage exceeds the inverter maximum voltage? -
ANSWERThe inverter may be damaged, or possibly void warranty.
What happens when the inverter is receiving less voltage than the inverter minimum? -
ANSWERInverter will go offline, and quit producing
What is the most common residential electrical service in the United States? -
ANSWER- Split Phase
- Single Phase
- Three Wire System
What voltage is a split phase residential electrical service? - ANSWER120/240 VAC
What is a Hertz? - ANSWERcycles per second/measure of frequency
What is the standard frequency of power in the United States? - ANSWER60 Hz
What are the three limits to solar system sizes? - ANSWER- Space
- Budget
- Energy Loads, or Production limitations
ANSWERS(RATED A+)
What is the most common PV system configuration in North America? - ANSWERNet-
metered grid-direct system
What happens to a grid direct system when the power goes down? - ANSWERThe
inverter is designed/required per UL and IEEE standards to shut off instantly. No grid
power, no solar power.
What terminals are connected in a series connection/PV source circuit? -
ANSWERPositive to Negative
In a series string what happens to the current and voltage? - ANSWERCurrent remains
the same, and voltage is additive
According to the NEC, what is the official name of a series string? - ANSWERPV
Source Circuit
After making a series string, what is done with the remaining terminals? - ANSWERThe
positive on one module, and the negative on the other become the "homerruns" or leads
What tool do you use to ensure your series connections are wired properly? -
ANSWERDigital Multimeter
How can you tell if all panels are working in a series string? - ANSWERThe voltage
should equal the open circuit voltage of all panels added together.
How does the power compare when if you were to wire the same two panels in series
then in parallel? - ANSWERThey would be the same
How do you wire modules in parallel? - ANSWERThe like terminals are connected
together... + to + and - to -
When modules are wired in parallel, what happens to the voltage? - ANSWERIt remains
the same
When multiple modules are wired in parallel at the combiner box, what is the output
wiring considered? - ANSWERPV Output Circuit
What tool is used to measure cell temperature? - ANSWERA temperature gun
How does irradiance impact voltage? - ANSWERIt has a very small impact
, What happens to the current as the irradiance increases? - ANSWERThe current
increases
What effect does irradiance have on current? - ANSWERAs one goes up, the other
goes up
At what point does irradiance start to have an effect on voltage? - ANSWER500 w/m^2
and below you may begin to notice 5-10% below what you would expect based on the
cell temperature at the time
What tool is used to measure irradiance? - ANSWERPyranometer
If my rated Imp of a module is 8 Amps, and my irradiance is 500 W/m^2 what would be
my expected current reading? - ANSWER4 Amps
What is the solar azimuth angle? - ANSWERThe position of the sun relative to North
What is the solar altitude angle? - ANSWERThe sun's position in degrees above the
horizon.
What is the tilt angle? - ANSWERThe degrees from flat that an array is angled
What is solar noon - ANSWERthe time of the day when the sun is at its highest point in
the sky
What may happen if the array voltage exceeds the inverter maximum voltage? -
ANSWERThe inverter may be damaged, or possibly void warranty.
What happens when the inverter is receiving less voltage than the inverter minimum? -
ANSWERInverter will go offline, and quit producing
What is the most common residential electrical service in the United States? -
ANSWER- Split Phase
- Single Phase
- Three Wire System
What voltage is a split phase residential electrical service? - ANSWER120/240 VAC
What is a Hertz? - ANSWERcycles per second/measure of frequency
What is the standard frequency of power in the United States? - ANSWER60 Hz
What are the three limits to solar system sizes? - ANSWER- Space
- Budget
- Energy Loads, or Production limitations
