NABCEP PV Installation Professional Exam
NABCEP North American Board of Certified Energy Practioners
JTA Job Task Analysis
The JTA outlines the expected duties of a qualified PV installation professional.
Conduit Fill NEC Chapter 9 Table 1
(i.e. Maximum Percent of Conduit Area Available for
Conductors)
Voltage Drop Limits 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 % 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 1-1/4"
AWG XHHW conductors, one size 8 AWG XHHW EGC
and four 10 AWG THHN conductors? Only use the NEC Use Chapter 9 Tables 4 and 5.
code book to answer this question.
BIPV Building-Integrated Photovoltaics
Can single phase inverters be connected to 3-phase Yes, as long as significant unbalanced voltages cannot result
power systems?
705.100
What is the minimum busbar rating for a subpanel used as 125A
an inverter ac combiner panel to combine three 4000W,
240V single phase inverters? 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 Yes, see 705.12(D).
of the main distribution panel?
But be careful that each panel in series meets the minimum busbar size
requirements.
Grounded conductor A current carrying conductor that is intentionally bonded to ground. It is the neutral
conductor in any AC system.
, NABCEP PV Installation Professional Exam
Equipment grounding conductor (EGC) The green or bare copper conductor linking exposed non-current-carrying metal
parts of module frames, equipment and enclosures
Grounding electrode conductor (GEC) The bare copper conductor connecting the system grounding bus to a ground rod or
to the earth.
Grounding electrode The rod or other buried electrode in the earth.
Grounding electrode system Several grounding electrodes effectively bonded together.
Sizing EGC The EGC should never be smaller than 14 AWG. Size the EGC according to Table
250.122
BOS Balance-of-System Components include all mechanical or electrical components
and hardware used to assemble and intergrate major components in a PV system
together (i.e. all components in a PV system except modules and inverters)
Stand-alone PV systems PV systems that operate independently of other electrical systems.
Interactive PV systems PV systems that operate in parallel with the electric utility grid.
Solar azimuth The direction of the sun's horizontal projection relative to a point on earth.
Solar altitude The sun's elevation above the horizon.
Sun path A graphical representation of the sun's altitude and azimuth angles over a given day
of the year.
Solar noon The local time when the sun is at its highest point in the sky and crossing the local
meridian (line of longitude).
Solar window The range of sun paths for a specific latitude between the winter and summer
solstices
Solar declination The ever changing angle between the earth's equatorial plane and the sun's rays.
Array azimuth angle The direction an array surface faces relative to due South.
NABCEP North American Board of Certified Energy Practioners
JTA Job Task Analysis
The JTA outlines the expected duties of a qualified PV installation professional.
Conduit Fill NEC Chapter 9 Table 1
(i.e. Maximum Percent of Conduit Area Available for
Conductors)
Voltage Drop Limits 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 % 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 1-1/4"
AWG XHHW conductors, one size 8 AWG XHHW EGC
and four 10 AWG THHN conductors? Only use the NEC Use Chapter 9 Tables 4 and 5.
code book to answer this question.
BIPV Building-Integrated Photovoltaics
Can single phase inverters be connected to 3-phase Yes, as long as significant unbalanced voltages cannot result
power systems?
705.100
What is the minimum busbar rating for a subpanel used as 125A
an inverter ac combiner panel to combine three 4000W,
240V single phase inverters? 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 Yes, see 705.12(D).
of the main distribution panel?
But be careful that each panel in series meets the minimum busbar size
requirements.
Grounded conductor A current carrying conductor that is intentionally bonded to ground. It is the neutral
conductor in any AC system.
, NABCEP PV Installation Professional Exam
Equipment grounding conductor (EGC) The green or bare copper conductor linking exposed non-current-carrying metal
parts of module frames, equipment and enclosures
Grounding electrode conductor (GEC) The bare copper conductor connecting the system grounding bus to a ground rod or
to the earth.
Grounding electrode The rod or other buried electrode in the earth.
Grounding electrode system Several grounding electrodes effectively bonded together.
Sizing EGC The EGC should never be smaller than 14 AWG. Size the EGC according to Table
250.122
BOS Balance-of-System Components include all mechanical or electrical components
and hardware used to assemble and intergrate major components in a PV system
together (i.e. all components in a PV system except modules and inverters)
Stand-alone PV systems PV systems that operate independently of other electrical systems.
Interactive PV systems PV systems that operate in parallel with the electric utility grid.
Solar azimuth The direction of the sun's horizontal projection relative to a point on earth.
Solar altitude The sun's elevation above the horizon.
Sun path A graphical representation of the sun's altitude and azimuth angles over a given day
of the year.
Solar noon The local time when the sun is at its highest point in the sky and crossing the local
meridian (line of longitude).
Solar window The range of sun paths for a specific latitude between the winter and summer
solstices
Solar declination The ever changing angle between the earth's equatorial plane and the sun's rays.
Array azimuth angle The direction an array surface faces relative to due South.
