NABCEP PV Installation Professional Exam
Questions with Correct Answers
NABCEP Correct Answer-North American Board of Certified Energy
Practioners
JTA Correct Answer-Job Task Analysis
The JTA outlines the expected duties of a qualified PV installation
professional.
Conduit Fill
(i.e. Maximum Percent of Conduit Area Available for Conductors)
Correct Answer-NEC Chapter 9 Table 1
Voltage Drop Limits Correct Answer-ASHRAE 90.1 Standards suggests
no more than 3% of nominal voltage.
NEC suggests no more than 5% in an "Informational Note".
Sunpower standard is no more than 1%.
Voltage Drop Equation Correct Answer-% drop =(0.2 x D x I x R )/V
Where:
D= one-way distance (in feet)
,I = current (nominal actual value, no 125% factors, use Imp for solar
circuits)
R = resistance of conductors (in ohms/1000ft)
V = voltage (typical, nominal, use Vmp for solar circuits)
Resistance values can be found in NEC Chapter 9 Table 8 "Conductor
Properties"
What size FMC conduit should be used for four size 6 AWG XHHW
conductors, one size 8 AWG XHHW EGC and four 10 AWG THHN
conductors? Only use the NEC code book to answer this question.
Correct Answer-1-1/4"
Use Chapter 9 Tables 4 and 5.
BIPV Correct Answer-Building-Integrated Photovoltaics
Can single phase inverters be connected to 3-phase power systems?
Correct Answer-Yes, as long as significant unbalanced voltages cannot
result
705.100
What is the minimum busbar rating for a subpanel used as an inverter ac
combiner panel to combine three 4000W, 240V single phase inverters?
Correct Answer-125A
, Rating of each breaker = 16.7 X 1.25 = 25A
Sum of inverter breakers = 3 x 25A = 75A
Minimum size of back-fed breaker in main service panel = 3 x 16.7A x
1.25 = 62.2 --> 70A
Minimum size busbars in subpanel x 1.2 = inverter breakers + utility
breaker = 75A + 70A
Minimum size busbars in subpanel = (75A + 70A)/1.2 = 121 --> 125A
705.12(D)(2)
Can an inverter output be connected to a subpanel instead of the main
distribution panel? Correct Answer-Yes, see 705.12(D).
But be careful that each panel in series meets the minimum busbar size
requirements.
Grounded conductor Correct Answer-A current carrying conductor that
is intentionally bonded to ground. It is the neutral conductor in any AC
system.
Questions with Correct Answers
NABCEP Correct Answer-North American Board of Certified Energy
Practioners
JTA Correct Answer-Job Task Analysis
The JTA outlines the expected duties of a qualified PV installation
professional.
Conduit Fill
(i.e. Maximum Percent of Conduit Area Available for Conductors)
Correct Answer-NEC Chapter 9 Table 1
Voltage Drop Limits Correct Answer-ASHRAE 90.1 Standards suggests
no more than 3% of nominal voltage.
NEC suggests no more than 5% in an "Informational Note".
Sunpower standard is no more than 1%.
Voltage Drop Equation Correct Answer-% drop =(0.2 x D x I x R )/V
Where:
D= one-way distance (in feet)
,I = current (nominal actual value, no 125% factors, use Imp for solar
circuits)
R = resistance of conductors (in ohms/1000ft)
V = voltage (typical, nominal, use Vmp for solar circuits)
Resistance values can be found in NEC Chapter 9 Table 8 "Conductor
Properties"
What size FMC conduit should be used for four size 6 AWG XHHW
conductors, one size 8 AWG XHHW EGC and four 10 AWG THHN
conductors? Only use the NEC code book to answer this question.
Correct Answer-1-1/4"
Use Chapter 9 Tables 4 and 5.
BIPV Correct Answer-Building-Integrated Photovoltaics
Can single phase inverters be connected to 3-phase power systems?
Correct Answer-Yes, as long as significant unbalanced voltages cannot
result
705.100
What is the minimum busbar rating for a subpanel used as an inverter ac
combiner panel to combine three 4000W, 240V single phase inverters?
Correct Answer-125A
, Rating of each breaker = 16.7 X 1.25 = 25A
Sum of inverter breakers = 3 x 25A = 75A
Minimum size of back-fed breaker in main service panel = 3 x 16.7A x
1.25 = 62.2 --> 70A
Minimum size busbars in subpanel x 1.2 = inverter breakers + utility
breaker = 75A + 70A
Minimum size busbars in subpanel = (75A + 70A)/1.2 = 121 --> 125A
705.12(D)(2)
Can an inverter output be connected to a subpanel instead of the main
distribution panel? Correct Answer-Yes, see 705.12(D).
But be careful that each panel in series meets the minimum busbar size
requirements.
Grounded conductor Correct Answer-A current carrying conductor that
is intentionally bonded to ground. It is the neutral conductor in any AC
system.
