SOLAR RSI QUESTIONS AND ANSWERS
What is system availability when sizing a system? - Answer -Percentage of time over a
year the system meets load requirements
When selecting a battery bank what determines its required capacity? - Answer -The
autonomy period during the critical month.
What is the fine balance required when sizing a stand alone system? - Answer -Supply
vs Demand
In critical design, the ratio of energy demand to insulation is found how often? - Answer
-Each month
In a hybid system design what is the typical range of solar to engine generator ratios? -
Answer -90% PV 10% Generator
When selecting an inverter what load should the inverter be rated for? - Answer -
Slightly higher than the largest AC load
What are the main limitations when sizing an interactive system? - Answer -Space for
the array and customers budget
In system sizing what is the simplest type of PV system to size? - Answer -Utility
Interactive
When sizing a Bi Modal system which loads should you consider? - Answer -Critical
loads
The percentage of the time the load is operating is called - Answer -Duty cycle
When PV modules are substituted for regular building materials this mounting is called?
- Answer -Building integrated
Which building mounting systems are used most commonly? - Answer -Direct, Rock
and stand off mounted
What is the advantage of self ballasting mounts? - Answer -No roofing penetrations
What is the term for electro mechanical reaction between 2 metals corroding the weaker
metal. - Answer -Galvanic Corrosion
Which tracking system gains the most solar irradiance regardless of cost? - Answer -2
Axis
, What structural loads do we consider when designing a PV array? - Answer -Gravity,
Environmental, and Mechanical loads
Why is it important to keep the array modules cool? - Answer -Array will last longer and
operate more efficiently
The safest and most practical means to access equipment and wiring is called? -
Answer -Accessibility
What applications are appropriate for pole mounted systems? - Answer -Ground
mounted system with shading potential
Which materials are best used for mechanical BOS? - Answer -Hot dipped galvanized
or coated steel, stainless steel 316 and 403, and aluminum 6061 and 6063
When there are more than 3 current carrying wires in a conduit longer than 24"? -
Answer -Further derate the conductor ampacity
When can the max inverter current exceed nominal ratings for battery based systems? -
Answer -When the highest input current is matched with the lowest inverter operating
voltage.
What is a PV combiner used for? - Answer -A parallel connection point for 2 or more
array series
What correction factor would you use to determine Maximum PV circuit current? -
Answer -125% (1.25)
What current carrying connections does not need to be made with a junction box? -
Answer -Special connectors attached from module to module.
What correction factor is used to calculate PV maximum output voltage per NEC? -
Answer -Low temp correction factor.
The word used for a current a wire can carry without exceeding its temperature rating? -
Answer -Ampacity
What properties define the material of a wires insulation? - Answer -Temperature,
Environment, and Location
What effects the wire ampacity? - Answer -Temperature, AWG and current
Where are the low temperature corrections found for calculating VOC for an array? -
Answer -Module manufacture specs and NEC 690.7
What parts of a PV system are typically grounded? - Answer -AC, DC and Array
What is system availability when sizing a system? - Answer -Percentage of time over a
year the system meets load requirements
When selecting a battery bank what determines its required capacity? - Answer -The
autonomy period during the critical month.
What is the fine balance required when sizing a stand alone system? - Answer -Supply
vs Demand
In critical design, the ratio of energy demand to insulation is found how often? - Answer
-Each month
In a hybid system design what is the typical range of solar to engine generator ratios? -
Answer -90% PV 10% Generator
When selecting an inverter what load should the inverter be rated for? - Answer -
Slightly higher than the largest AC load
What are the main limitations when sizing an interactive system? - Answer -Space for
the array and customers budget
In system sizing what is the simplest type of PV system to size? - Answer -Utility
Interactive
When sizing a Bi Modal system which loads should you consider? - Answer -Critical
loads
The percentage of the time the load is operating is called - Answer -Duty cycle
When PV modules are substituted for regular building materials this mounting is called?
- Answer -Building integrated
Which building mounting systems are used most commonly? - Answer -Direct, Rock
and stand off mounted
What is the advantage of self ballasting mounts? - Answer -No roofing penetrations
What is the term for electro mechanical reaction between 2 metals corroding the weaker
metal. - Answer -Galvanic Corrosion
Which tracking system gains the most solar irradiance regardless of cost? - Answer -2
Axis
, What structural loads do we consider when designing a PV array? - Answer -Gravity,
Environmental, and Mechanical loads
Why is it important to keep the array modules cool? - Answer -Array will last longer and
operate more efficiently
The safest and most practical means to access equipment and wiring is called? -
Answer -Accessibility
What applications are appropriate for pole mounted systems? - Answer -Ground
mounted system with shading potential
Which materials are best used for mechanical BOS? - Answer -Hot dipped galvanized
or coated steel, stainless steel 316 and 403, and aluminum 6061 and 6063
When there are more than 3 current carrying wires in a conduit longer than 24"? -
Answer -Further derate the conductor ampacity
When can the max inverter current exceed nominal ratings for battery based systems? -
Answer -When the highest input current is matched with the lowest inverter operating
voltage.
What is a PV combiner used for? - Answer -A parallel connection point for 2 or more
array series
What correction factor would you use to determine Maximum PV circuit current? -
Answer -125% (1.25)
What current carrying connections does not need to be made with a junction box? -
Answer -Special connectors attached from module to module.
What correction factor is used to calculate PV maximum output voltage per NEC? -
Answer -Low temp correction factor.
The word used for a current a wire can carry without exceeding its temperature rating? -
Answer -Ampacity
What properties define the material of a wires insulation? - Answer -Temperature,
Environment, and Location
What effects the wire ampacity? - Answer -Temperature, AWG and current
Where are the low temperature corrections found for calculating VOC for an array? -
Answer -Module manufacture specs and NEC 690.7
What parts of a PV system are typically grounded? - Answer -AC, DC and Array
