NABCEP PV ASSOCIATE EXAM
QUESTIONS AND ALL ACTUAL
ANSWERS.
An off-grid installation has a 1HP pump that is on 10% of the time and a 20W light that is on 100% of the
time. What is the monthly energy use? - Answer 68KWh
1HP = 746W
746W * 0.1 * 24hours * 30days = 53712Wh
20W * 24hrs * 30days = 14400Wh
14400 + 53712 = 68112Wh
68kWh
What kind of ground faults do most inverters detect? - Answer DC
Inverters detect dc ground faults. AC ground faults are detected on the AC side of the inverter at the
distribution paned (MSP, load center). Most inverters are not connected to high or medium voltage.
Medium voltage is thousands of volts, large utility scale inverters are connected to medium voltage via a
transformer
Current carrying ability of a conductor (wire) is called - Answer Ampacity
According to ohms law and voltage drop, the relationship between voltage drop and current is - Answer
Proportional. Ohms law: V = I*R
More current makes more voltage drop. This is a reason why we need a larger wire with more current, so
the wire resistance is less with a larger wire and there will be less voltage drop.
An array in a hot and dry place is not producing as expected in summer time. Which of the following is
NOT a likely problem:
a) Decreased ac wire size and voltage loss
b) String size too short
C) String size too long
,D) Soiling - Answer C) String size too short. When it is hot, voltage can be low. Too long of a string
would be a problem when it is too cold not too hot.
When using a digital multimeter, what is the first thing you should do? - Answer Inspect the meter.
Always inspect first, look before you touch
is the worst design error?
A) BIPV on a commercial job
B) A fast-growing tree to the north of an array in Idaho
C) PV at 5-degree tilt at 40 degrees latitude
D) Different tilt angles in a PV source circuit - Answer D) Different tilt or azimuth operation within a
source circuit is bad. Series connections should not have different orientations
MPPT is for - Answer MPPT is maximum power point tracking and will optimize the energy harnessed
from PV. Some inverters have multiple MPPTs. Charge controllers often, but don't always, have MPPTs
Concentrated PV:
A) Only works with direct sunlight
B) Usually has a single axis tracker
C) Will get 30% power during cloudy conditions
D) Is using heat to make electricity - Answer A) Only works in direct sunlight. usually works with 2-axis
trackers to always point at the sun and will not work at all in cloudy conditions. Concentrated PV =!
Concentrating Solar thermal
Fall protection should be used at heights over - Answer 6 feet
Parallel PV circuit connections increase - Answer Parallel increase current. Series increase voltage
Optimal tilt for off-grid PV system in the winter - Answer Latitude + 15 degrees is Optimal tilt to
maximize winter production. The sun is lower in the winter, requiring a higher tilt angle
, What is the most acceptable rating of an enclosure for exposed circuit conductors mounted on an
outside wall? - Answer NEMA 3R
Bypass diodes are located in the
A) Combiner box
B) Inverter
C) Wiring harness
D) PV Module - Answer Bypass diodes are in PV module junction box. Diverts current around a group of
cells if one is shaded. Usually 3 diodes/PV module
PV array at higher elevation would tend to produce more - Answer Current. Higher elevation, less
atmosphere, more irradiance, more current. High elevation can also be cooler meaning more voltage
from cold temps.
How much 14% efficient PV fits on 25 Square Meters
A) 3000W
B) 4.5kW
C) 4000W
D) 3.5kW - Answer D) 3.5kW. 14% efficient = 0.14*1000W/M^2 = 140 W/m^2
140 * 25 = 3500W = 3.5kW
Which is the smallest conductor? - Answer 18 AWG
18 AWG, 10 AWG, 0 AWG, 3/0 AWG
What is the simplest type of PV system - Answer Direct coupled is the simplest with just PV and a load
that only works when the sun is out
Sun path charts differ based on - Answer Latitude
Series connections increase - Answer Voltage. Parallel increases current
QUESTIONS AND ALL ACTUAL
ANSWERS.
An off-grid installation has a 1HP pump that is on 10% of the time and a 20W light that is on 100% of the
time. What is the monthly energy use? - Answer 68KWh
1HP = 746W
746W * 0.1 * 24hours * 30days = 53712Wh
20W * 24hrs * 30days = 14400Wh
14400 + 53712 = 68112Wh
68kWh
What kind of ground faults do most inverters detect? - Answer DC
Inverters detect dc ground faults. AC ground faults are detected on the AC side of the inverter at the
distribution paned (MSP, load center). Most inverters are not connected to high or medium voltage.
Medium voltage is thousands of volts, large utility scale inverters are connected to medium voltage via a
transformer
Current carrying ability of a conductor (wire) is called - Answer Ampacity
According to ohms law and voltage drop, the relationship between voltage drop and current is - Answer
Proportional. Ohms law: V = I*R
More current makes more voltage drop. This is a reason why we need a larger wire with more current, so
the wire resistance is less with a larger wire and there will be less voltage drop.
An array in a hot and dry place is not producing as expected in summer time. Which of the following is
NOT a likely problem:
a) Decreased ac wire size and voltage loss
b) String size too short
C) String size too long
,D) Soiling - Answer C) String size too short. When it is hot, voltage can be low. Too long of a string
would be a problem when it is too cold not too hot.
When using a digital multimeter, what is the first thing you should do? - Answer Inspect the meter.
Always inspect first, look before you touch
is the worst design error?
A) BIPV on a commercial job
B) A fast-growing tree to the north of an array in Idaho
C) PV at 5-degree tilt at 40 degrees latitude
D) Different tilt angles in a PV source circuit - Answer D) Different tilt or azimuth operation within a
source circuit is bad. Series connections should not have different orientations
MPPT is for - Answer MPPT is maximum power point tracking and will optimize the energy harnessed
from PV. Some inverters have multiple MPPTs. Charge controllers often, but don't always, have MPPTs
Concentrated PV:
A) Only works with direct sunlight
B) Usually has a single axis tracker
C) Will get 30% power during cloudy conditions
D) Is using heat to make electricity - Answer A) Only works in direct sunlight. usually works with 2-axis
trackers to always point at the sun and will not work at all in cloudy conditions. Concentrated PV =!
Concentrating Solar thermal
Fall protection should be used at heights over - Answer 6 feet
Parallel PV circuit connections increase - Answer Parallel increase current. Series increase voltage
Optimal tilt for off-grid PV system in the winter - Answer Latitude + 15 degrees is Optimal tilt to
maximize winter production. The sun is lower in the winter, requiring a higher tilt angle
, What is the most acceptable rating of an enclosure for exposed circuit conductors mounted on an
outside wall? - Answer NEMA 3R
Bypass diodes are located in the
A) Combiner box
B) Inverter
C) Wiring harness
D) PV Module - Answer Bypass diodes are in PV module junction box. Diverts current around a group of
cells if one is shaded. Usually 3 diodes/PV module
PV array at higher elevation would tend to produce more - Answer Current. Higher elevation, less
atmosphere, more irradiance, more current. High elevation can also be cooler meaning more voltage
from cold temps.
How much 14% efficient PV fits on 25 Square Meters
A) 3000W
B) 4.5kW
C) 4000W
D) 3.5kW - Answer D) 3.5kW. 14% efficient = 0.14*1000W/M^2 = 140 W/m^2
140 * 25 = 3500W = 3.5kW
Which is the smallest conductor? - Answer 18 AWG
18 AWG, 10 AWG, 0 AWG, 3/0 AWG
What is the simplest type of PV system - Answer Direct coupled is the simplest with just PV and a load
that only works when the sun is out
Sun path charts differ based on - Answer Latitude
Series connections increase - Answer Voltage. Parallel increases current
