NABCEP Practice Exam
what kind of ground faults do most inverters detect?
a.hight voltage
b.medium voltage
c.AC
d.DC - ANS - D. Inverters detect dc ground faults(when positive in contact
with ground wire)in most in
...
NABCEP Practice Exam
what kind of ground faults do most inverters detect?
a.hight voltage
b.medium voltage
c.AC
d.DC - ANS - D. Inverters detect dc ground faults(when positive in contact
with ground wire)in most inverters.
Current carrying ability of a conductor(wire)is called.
a.Ampacity
b. Amps
c. inductance
d. insolation - ANS - A. Current carrying ability is ampacity
According to ohms law and voltage drop, the relationship between voltage and current is.
a. Proportional
b.Inversely proportional
c.Directly inverse
d.inversely direct - ANS - A. Voltage and current are proportional.
More current makes more voltage drop
An Array in Sacramento California in August is not producing as expected. Which of the
following is NOT a likely problem.
a.Decrease ac wire size and voltage loss
b.string size too short
c.string size too long
d.soiling - ANS - C.Late summer is hot and can be dry. When it is hot, voltage can be low.Too
long of a string would be a problem when it too cold, not hot.Pay attention to the world Not in
question.
When using a digital multimeter, what is the first thing you should do?
a.Turn the meter on
b.inspect the meter
c.Touch the black lead to the white wire
d.Touch the black lead to the black wire - ANS - B.Inspect the meter
Which is the worst design error?
a.BIPV on commercial job
b.A fast growing tree to the north of the array in idaho
c.Pv at 5 degree tilt at 40 degrees latitude
d.Different tilt angles in PV source circuit - ANS - D. different tilt or azimuth orientation within
a source circuit is bad.
MPPT is for
a.Optimizing energy from the utility
b.Getting the most energy from a battery with a MPPT inverter
c.Optimizing power from a PV array
d.Tracking the sun with a 2-axis tracker - ANS - C.Mppt is maximum power point tracking and
will optimize the energy harnessed from PV.
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 - ANS - A.Concentrated PV only works with direct sunlight
Fall protection should be used at heights over
a.4 feet
b.2 feet
c.3 feet
d.6 feet - ANS - D. 6 feet
Parallel PV circuit connections increase
a.Voltage
b.current
c.Resistance
d.EMF - ANS - B. Parallel connections increase current. Series increase Voltage.
Optimal tilt for off-grid PV system in winter
a.latitude
b.latitude -15 degrees
c.latitude +15 degrees
d.vertical - ANS - C. latitude +15 degrees. The sun is lower in the winter, which requires a
higher tilt
For a transformerless inverter,which type of wire should be used when exposed to the elements
outdoors on PV source circuits?
a.PV wire
b.THWN-2
c.USE-2
d.PV-2 - ANS - A. PV wire
A PV array at higher elevation would tend to produce more
a.Current
b.Heat
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