WorksheetsNABCEP PVA Practice Exam Mash Up #2
Total questions: 70
Worksheet time: 35mins
An ammeter in combination with which other kind of meter could measure power?
Ohmmeter
Voltmeter
Energy meter
Pyranometer
What is the most cost effective, yet sufficient method for marking for a PV label?
Handwriting with permanent marker
Engraving on a NEMA rated disconnect
Permanent sticker
Handwriting on permanent sticker indoors only
Which component most commonly has a fuse in a modern PV system?
Inverter
Dc-to-dc converter
PV module junction box
Dc combiner
What is BIPV?
PV that also replaces building materials
PV that can absorb solar energy from both sides to take advantage of reflected light
PV that is both positively and negatively grounded
PV that is transparent
What does autonomy refer to when sizing a battery bank?
The battery bank is consisting of only one type of battery chemistry
The battery cells are all connected in one series string
The battery management system can control the charge/discharge without human input
How long a battery bank can last without being charged
What would be the expected output at Standard Test Conditions for a PV module with 20 PV sources in series, each with a circuit Voc of 44V, Vmp of 35.2V, power of 305W, and Isc of 9.27A?
704V and 8.66A
600V and 8A
1000V and 8.2A
700V and 9.27A
What is the power of the array at STC?
There are 4 PV source circuits of 10 PV modules each
Given: Module information: Power = 250W, Open Circuit Voltage = 40V, Maximum Power Voltage = 35V,
Short Circuit Current = 8A, Maximum Power Current = 7.14A, Temp Coefficient for Voltage −0.33%/°C, CEC Power 220W,
NOCT 48°C Inverter information: Low MPPT voltage 230V, Inverter maximum input voltage 550V.
10kW
110kW
1000W
40kW
What kind of PV system is used so that people have power if the utility ceases to exist, but can still work with the utility?
Stand-alone
Direct-coupled
Multimode
Grid-tied hybrid
If we wanted to calculate an average power, what would we do mathematically?
a. Take demand charges and divide by time
b. Divide energy by time
c. Divide Ah by time
d. Divide resistance by power
Which characteristics of a wire would lead to more voltage drop?
a. Long and wide
b. Short and wide
c. Long and thin
d. Short and thin
What is the most appropriate and cost-effective rating of an enclosure for exposed circuit conductors mounted on an outside wall?
NEMA 3R
NEMA 11
NEMA 4X
NEMA 12
Which is the best tilt angle for annual production in most of the USA (temperate latitudes)?
Latitude +15 degrees
Latitude -15 degrees
30 degrees
Longitude tilt
What is the total energy produced when a 500W/m² solar irradiance is applied over an area for 4 hours?
20kWh/m²
2kWh/m²
2kW/m²
5kW
When considering the critical design month for a stand-alone PV system, which scenario is typically most challenging?
Best insolation and most load usage
Worst insolation and most load usage
Worst insolation and least load usage
Best insolation and least load usage
What is the recommended method for roofers to prevent water intrusion at structural attachments?
Caulking around the screw
Extrusions
Flashing
Syzygy
Which of the following is used to calculate maximum system voltage?
Current
Power
Temperature
Irradiance
A PV system that would produce 7kWac under STC conditions, which is not clipping power, is installed in a location with an average of 6PSH (peak sun hours, aka kWh/square meter per day average) would produce how much energy in one year?
14,008 kWh
1,503 kWh
3,307 kWh
15,330 kWh
Optimal tilt for off-grid PV system in the winter
Latitude
Latitude −15 degrees
Latitude +15 degrees
Vertical
What color wires can be used for equipment grounding (earthing is international term) wires in the US?
Green, Bare or Green with Yellow stripe
White or Blue
Yellow or Blue
Any color
Direction on a compass is
Latitude
Longitude
Meridian
Azimuth
On a non-isolated functionally grounded (formerly known as ungrounded in the 2014 NEC) PV array, what does the equipment grounding conductor do or is there a requirement to have an equipment grounding conductor?
Ensure that neutrals are referenced to ground potential
Cause a common reference point of system grounding
There is no requirement to have an equipment grounding conductor on a non-isolated functionally grounded system.
Prevent shock from exposed equipment
You are rebuilding an old battery system for a PV museum and everything is in amps and amp hours. You are told that the system needs to have 33% more PV
production on average than what the loads require. The loads will require 20Ah per day and the insolation will be 5PSH. If the module current at STC is 8A at Imp
and 9A at Isc, how many PV source circuits would be needed to meet the minimum requirements stated here?
1
2
3
4
Besides calculations, where can we find out what would be the maximum series fuse rating of a PV module?
On the back of the module
On the PV wire instructions
By multiplying Imp x 1.56 and rounding up to the next common fuse size
By multiplying Isc x 1.25 and rounding up to the next common fuse size
What is the highest angle which the sun can be anywhere in the world?
23.5 degress
45 degrees
90 degrees
180 degrees
Which type of circuit has to have the wire and equipment sized based on at least 156% of short circuit current?
PV source circuits
Dc-to-dc converter source circuits
Interactive inverter output circuits
Stand-alone inverter input circuits
An arc is caused by higher
Voltage
Current
Resistance
Energy
Which tilt angle from horizontal would get the best annual production from a location in Toronto at 43 degrees north?
42 degrees
58 degrees
15 degrees
20 degrees
What is “blocking” used for?
Bypass diodes
Attaching to a roof in a place where there is no rafter
Leveling off a parapet
Inserting reverse current into a circuit to prevent forward bias current
Best sealant for residential rooftop
Polyurethane
Paraffin
Bitumen
Silicon
What kind of ground faults do most inverters detect?
High voltage
Medium voltage
AC
DC
What would be the most practical way to add battery backup to an existing grid-tied system?
Grid defection system
Reinstalling the system
Ac-coupled
Dc-coupled
A PV array produces 10kWh in a day in a location with 5 peak sun hours and a nominal battery voltage of 24V. What is the minimum required wire ampacity of the following for the PV output circuit?
15A
150A
300A
400A
How long do PV module manufacturers generally warranty their modules for?
10 years for materials and 10 years for performance
25 years for materials and 25 years for performance
25 years for materials and 10 years for performance
10 years for material and 25 years for performance
A supply-side connection will have the PV interconnection between the ________ and the ________.
Meter, main breaker
Main breaker, subpanel
Service fused disconnect and main panel in basement
Meter-main combo and subpanel
Where can you find the requirements for rapid shutdown of PV systems on buildings?
UL
OSHA
NFPA 70
IRC
There is a system with 4 concrete pavers (weights) securing it on a rooftop. What kind of system is this?
Ballast rack mount
Ballast standoff
East-west tilt mount
Single axis-tracker
In the image below of an IV curve, which point mostly represents the MPP on a hot day?
A
B
C
D
Which of the following would be considered a dead load on the roof of a building?
Lift from wind
Snow drift temporarily built up under an array
PV modules and racking
A hail storm
Which of the following must be included as part of an emergency action plan for OSHA?
Job specific PPE
Procedure for reporting of fires
Module specification sheets
Types of module used for the system
Where should you direct a pyranometer to get the most accurate irradiance reading for your array?
At the horizon
Directly south
In the plane of the array
Away from shading
Which of the following will show system components and connections?
Electrical diagram
Sunpath chart
Module spec sheet
IV curve chart
In jurisdictions where class A fire rated roofing is required, what classification must
PV modules have to be installed on buildings?
UL 9540 or 1973 and Class A or B
UL 9540 and Class A
UL 1703 or 61730 and Class A
UL 1703 or 61730 and Class A or B
Which is the best order of steps to complete before removing equipment during
troubleshooting and maintenance.
Replace fuses, open disconnects, isolate equipment
Open ac and dc disconnects, check breakers, test voltages
Open ac and dc disconnects, isolate equipment, test voltages
Test voltages, check breakers, replace fuses
How far above the roof should an extension ladder be?
1:4 feet
3 meters
≥ 3ft
< 3feet
After it is determined that there is adequate space on the roof, what is the next
step?
Shade analysis
Connecting inter-module strings
Sending proposal to customer
Putting together a permit
Of the following, which is the best benefit of a PV system for a homeowner?
VAR support
Demand response
Self-consumption
Backup power
What would be most important to measure when comparing actual vs. expected
performance as part of commissioning a typical ground mounted PV system?
Imp and Isc
Isc and Voc
Voc and Vsc
Imp and Vmp
Which battery voltage would minimize conductor costs the most?
12V
24V
48V
400V
A PV source circuit requires an overcurrent protection device and the short circuit
current of the PV module is 12A. What size fuse would you use?
12A
10A
15A
20A
What is more likely to have to be replaced the soonest?
AC disconnect
PV module
Electronic Power Converter
MC connectors
What happens to a PV module when you short circuit it?
The PV module can break and needs to be replaced
Nothing much
The voltage goes up
The fuse bows or the bypass diode breaks
Traditional American net-metering is when you get credit for the rate of
energy when you are exporting energy to the grid.
Retail
Wholesale
Less than retail
Less than wholesale
How many silicon solar cells in series is best for charging a 12V lead-acid battery
if you are not using a MPPT charge controller?
20
36
60
72
What is the use case for an interactive PV system on a rooftop that does not have
an energy storage system associated with it?
Resilience in case of a power outage
Extra current for loads
Lower energy charges
Demand charge reduction
What is the proper slope of an extension ladder?
1:3
1:4
1:5
1:6
What do you often see in a solar service agreement (SSA) to ensure system performance?
Labor
Remote monitoring
Module 30-year warranty
Rebate delineation
Which level has the authority over enforcement of the NEC usually?
State
Federal
NFPA
Local
What does a hydrometer measure?
Water temperature
Specific gravity of battery acid
Lithium density
Surfactant levels
What is the NEC for?
Practical safeguarding of electrical equipment
Workplace safety for employees
Safety for testing electrical equipment
Practical safeguarding of persons and property
A performance guarantee is:
Something that can be spelled out in the fine print of a solar service agreement, such as a PPA or a solar lease and often tells a minimum of how much energy you should expect from your system.
On the label of the module and guarantees that the solar module will make a certain amount of power in a specified amount of time, such as 20 years.
On the datasheet of the module and guarantees that the solar module will make a certain amount of energy in a specified amount of time, such as 20 years.
Covers solar module construction and components over a specified period of time, such as 20 years.
A 50kW interactive PV system has 15% system losses in a location getting 5.4 peak sun hours per day average throughout the year. What would be the expected annual energy output?
2 MWh
44 kWh
8.3 kWh
83,768 kWh
The interconnection of a PV system is approved by
City
County
State
Utility
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 energy use per month?
54Wh
68kW
68kWh
0.63 MWh
Bypass diodes
Reduce current
Limit effects of shading
Are wired in series with groups of solar cells and prevent reverse current
Are in the combiner box
To ensure electrical safety, which of the following should be done first?
Open dc disconnect
Open ac disconnect
Close all disconnects
Identify all power sources
What part of the permit process addresses manufacturers’ warranties?
Racking design
PV plan sets
Engineered drawings
Equipment specifications
For a supply-side connection, the output of the inverter is limited by
Service entrance conductor ampacity
Load side breaker ampacity
PV dimension and quantity
Locational irradiance
What is the C rate of a 100Ah battery at 5A?
5C or C/5
0.05C or C/20
500C or C/100
100C or C/100
Which PPE should be used when working at voltages over 600V?
Insulated gloves
Torque screwdriver
Lifeline
Pyranometer
What power percentage of PTC is STC?
75%
156%
108%
25%
