Score 0 of 1
Question:
The grounded PV conductor size 6AWG or less used for wiring from the combiner box to the inverter must not be
Response:
| solid blue
|
Feedback: NEC200.6(A): White, gray or any color with 3 white stripes.
|
| solid white
|
| solid gray
|
| blue with 3 white stripes
|
Score 0 of 1
Question:
A residence has a 200A service panel with a 150A main circuit breaker to the utility. What is the highest rated inverter continuous AC output that can be backfed into this Main Service Panel?
Response:
| 72
|
| 84
|
| 85
|
Feedback: NEC705.12(D)(2): Sum of OCPD supplying power to busbar must not exceed 120% of the busbar rating.
Supply power maximum = 1.2 X 200= 240 amps
Maximum from solar = 240 - 150= 90 amps
|
| 94
|
Score 1 of 1
Question:
Which of the following is not true?
Response:
| PV source circuit OCPD can not be greater than overcurrent rating on module name plate.
|
| The minimum PV source circuit conductor ampacity before adjusting for conditions of use is calculated as Isc X 1.25.
|
Feedback: PV source circuit ampacity is = Isc X 1.25 X 1.25.
The first 1.25 multiplier is due to the potential for the sunlight to produce more current than it's rating.
The second 1.25 multiplier is due the continuous current flow of more than 3 hours.
|
| The ampacity rating of the OCPD must be adjusted per the manufacturer if operated at greater than 104 degrees F.
|
| For a grounded PV system only one conductor requires overcurrent protection.
|
Score 1 of 1
Question:
What AWG conductor size is required for the PV output circuit of 2 current carrying THWN-2 conductors in a circular raceway on the roof (< 1/2" above roof) supplied by 2 PV source circuits each having a Isc rating of 6.8A? Ambient temperature = 90deg F.
Response:
| 12
|
| 10
|
Feedback: NEC690.8(B)(1): Ampacity= Isc X 1.25 X 1.25 X factors of use.
NEC table 310.15(B): <0.5" from roof = add 60 degrees F
NEC table 310.15(B)(2)(A): ambient factor of 0.58 for 150F (90F + 60F)
Wire ampacity required: 2 X 6.8 X1.25 X 1.25 / 0.58= 36.6
NEC table 310.15(B)(16) 90F column= #10AWG
|
| 8
|
| 6
|
Score 1 of 1
Question:
Assume a home for a stand alone PV Solar system has a 3kwh/day average DC requirement. What 6 volt battery Ah rating is required assuming 8 batteries in series will be used? Autonomy is 3 days. Also assume the allowable depth of discharge is 80% and the charge/discharge efficiency of the batteries is 90%.
Response:
| 87
|
| 135
|
| 260
|
Feedback: Required DC energy= 3kwh 3=9kwh
Battery system voltage= 6X8=48V
Amp-hours required= 9k/48= 187.5Ah
Final Ah considering efficiency: 187.5 X 0.8 X 0.9= 260Ah
|
| 1283
|
Score 1 of 1
Question:
Which factor below is not a key factor affecting the usable capacity of a battery?
Response:
| Depth of discharge
|
Feedback: Depth of Discharge is a measurement of the battery status - it is not related to the basic usable capacity of a battery.
|
| Plate size
|
| Temperature
|
| Discharge Rate
|
Score 0 of 1
Question:
For interconnected electric power production sources, the following are all true except:
Response:
| The AC inverter can backfeed dedicated circuit breakers that are not marked "line" and "load"
|
| The dedicated AC inverter circuit breakers that are backfed must be secured in place by an additional fastener.
|
Feedback: NEC705.12(D)(6): Listed OCPD for inverters when identified need not follow 408.36(D)
|
| The AC inverter circuit breaker must be located at the opposite end from the input feeder supply conductors.
|
| A permanent warning label must be placed on the panel board to warn others that the inverter output connection circuit breaker must not be relocated.
|
Score 0 of 1
Question:
Which of the following is a NEC code violation?
Response:
| PV module frame equipment ground conductor occupying the same raceway with the grounded and ungrounded PV output conductors.
|
| AC and DC PV conductors occupying the same raceway without a physical barrier between them.
|
| A ground rod electrode with at least 6 ft in contact with the ground.
|
Feedback: NEC300.3(C)(1): AC and DC ok if <600V and NEC 690.4(B)
250.53(G): Grd Rod with at least 8ft in contact with soil
|
| A #6 AWG equipment ground conductor not protected from physical damage.
|
Score 1 of 1
Question:
What row to row spacing is required for a solar array facing directly south if the modules are 3 foot wide and are at a 10 degree tilt and shading is to be avoided when the sun is at 22 degrees above the horizon at 30 degrees east of south?
Response:
| 13.4 inches
|
Feedback: At a 10 degree tilt, the modules stick up 36 inches X cos 10 degrees = 6.2513 inches.
The length of shadow at 30 degrees east of south for the
sun at 22 degrees = 62513/tan22 degrees = 15.47 inches
The spacing required between row is = cos 30 degrees X 15.47 = 13.4 inches
|
| 15.5 inches
|
| 17.2 inches
|
| 18.1 inches
|
Score 0 of 1
Question:
Equipment such as raceways, cables, etc can be located above or below electrical equipment but must not extend more than _______ inches into the equipment's working space.
Response:
| 12 inches
|
| 8 inches
|
| 6 inches
|
Feedback: NEC110.26(A)(3): 6 inches
|
| 3 inches
|
Score 1 of 1
Question:
A PV installation location has a maximum wind uplift force of 69.1lb/sq ft on the 10 modules (15 sf ft each) planned for installation. What minimum length of lag screw thread is required to be imbedded in the rafters. The withdraw load per screw is 314 lbs/inch and 22 screws will be evenly space throughout the installation.
Response:
| 1
|
| 1.5
|
Feedback: Total module area = 10 X 15=150 sq ft
Total wind uplift = 69.1 X 150=10,365 lbs.
Each lag screw withdrawal force = 10,365/22=471 lbs.
Thus imbedded thread must be at least 471/314= 1.5 inches long
|
| 2
|
| 2.5
|
Score 1 of 1
Question:
The center of the grip of the operating handle of an over current protection device when at it's highest position cannot be higher than:
Response:
| 8ft 7in
|
| 7ft 7in
|
| 6ft 7in
|
Feedback: |
| 5ft 7in
|
Score 1 of 1
Question:
The required minimum horizontal working space in front of electrical equipment can be
Response:
| measured from the left edge of the equipment
|
| centered on the equipment
|
| shared between one or more pieces of equipment mounted on the same wall
|
| all of the above
|
Feedback: NEC110.26(A)(2): 30 inches width in front of equipment.
|
Score 1 of 1
Question:
A building owner wants to place PV Modules flat on his flat roof to power a sign 12 hours each night that draws 500watts. If the PV Modules generate 16 watt/sq feet at peak irradiance and the worst-case months average irradiance is 2.4 peak sun hours/day, what is the minimum square feet of PV Modules required? Assume the charge controller's efficiency is 95% and the loss factor for the remaining system is 80%.
Response:
| 119
|
| 164
|
| 195
|
| 206
|
Feedback: Nightly requirement= 500X 12= 6kwh
Solar daily peak production= 16 X 2.4= 38.4 w/sq ft DC peak
AC production= 38.4 X 0.8 X 0.95= 29.184 w/sq ft
Solar module area required= 6k/29.184= 205.6 sq ft
|
Score 1 of 1
Question:
For interconnected electric power production sources, the following are all true except:
Response:
| The AC inverter can backfeed dedicated circuit breakers that are not marked "line" and "load"
|
| The dedicated AC inverter circuit breakers that are backfed must be secured in place by an additional fastener.
|
Feedback: NEC705.12(D)(6): Listed OCPD for inverters when identified need not follow 408.36(D)
|
| The AC inverter circuit breaker must be located at the opposite end from the input feeder supply conductors.
|
| A permanent warning label must be placed on the panel board to warn others that the inverter output connection circuit breaker must not be relocated.
|
Score 1 of 1
Question:
Which of the following is not considered a power source for a Hybrid Power System?
Response:
| Wind
|
| Battery
|
Feedback: |
| Generator
|
| PV Solar
|
