Slides from the lecture presented April 10th, 2014 by Sarah Raymer, Director of Education and Training at SolPowerPeople- a solar training company.

1. NABCEP Exam Prep Review for PV
Installation & Tech Sales
A Review of Need-to-Know Key Concepts for NABCEP Exams
Sarah Raymer, AKA Ms. MOOC

2. Tips
Timing is everything
Get some sleep- what studies show
about retention
“Shake it off, Champ!”

3. Topics for today:
 Online tools for site assessment
 Performing "ball-park estimates”- the risks
 Grid Direct VS. battery-based systems
 Site Analysis: system layout and installation-
component location, NEC requirements, & effects on
performance and cost
 Equipment selection- component matching and utility
interconnection requirements

4. Resource will be provided:
 Array string calculations: effects of temperature, inverter
matching
 Solar resource assessment: Azimuth, magnetic declination
 Array sizing: by area, budget, energy demand
 Online resources for solar resource assessment (Peak Sun
Hours)
 Determining useable roof area and attachment points
required
 Trigonometry : tilt angles, shading obstructions

5. #SolarMOOC Resources
 Subject Matter Experts
 #SolarMOOC Academy dropdown menu option is
Subject Matter Experts
 ARCHIVE: #SolarMOOC Academy dropdown menu
 Most Recent Lessons2012 / 2013 Archive

6. Online tools for site assessment
 Google Earth - ruler and Azimuth tool
 Google Maps -
 “Classic maps” - ruler for rough estimate on sizing under
“Maps Labs”
 LIMITATIONS of tools and virtual assessment
 Trees grow
 Roof - hard to determine age / structural integrity
 Can not see obstructions - vents/pipes
 Can not achieve true shading analysis

7. Online tools for site assessment
 NREL PV Watts Calculator - multiple versions
 Solar resource
 Performance estimate
 ROI
 Google it: ”PV WATTS”
 Other professional proposal software will calculate more
accurate costs and ROI specific to the customer
 Ex. Rebates from utility & financing (effects ROI)
 Ex. Of programs- Energy Periscope, OnGrid Solar

8. Google Earth
• Measure lines, save for later viewing and sharing
• Measure azimuth degrees instantly, declination
preconfigured

9. Google- ruler tool and street view
• Measurements
• Azimuths
• Roof pitch
• Building height

10. PVWATTS from NREL
FREE online tool
NREL's PVWatts calculator determines the energy
production and cost savings of grid-connected PV
Systems.

11. Select your location...
& click "send to PVWatts".
Tweek a few things, click to calculate, and viola!

12. PV Watts Version 4 BETA

13. Site Analysis:
Solar resource and shading
 RESOURCES
 NREL - Data tables (PSH)
 Trig for shading analysis-
 Go to solpowerpeople.com
 Search for “trigonometry”:

14. Site Analysis:
Solar resource and shading
 Resources:
 Azimuth - production, shading
 Altitude - production, shading
 Solar window - year round production assessment
 Magnetic declination - accurate production and shading
Site assessment
fundamentals

15. Performing "ball-park estimates"-
the risks
 Online calculated area is not an accurate
calculation of system size potential
 Must visit site-
 Obstructions
 Shade
 Mechanical considerations- roof trusses
 Area efficiency not same as module efficiency
 Power (kW), Area (m2), Efficiency
 DC vs. AC

16. Performing "ball-park estimates"-
the risks
 Costs may change depending on site specific
conditions
 Roof mount - type and age
 Pole or Ground mount - soil- rock?
 Roof tilt - not easy to determine online
 Be sure customer is aware of utility charges when
considering expected bills
 Return on Investment (ROI)
 Utility buyback policies

17. Performing "ball-park estimates"-
the risks
 Resources:
 #SolarMOOC Subject Matter Experts page:
 Determine required attachments
 Determine # of modules that will fit in area
 Area, Budget and Energy demand sizing estimates
Ball park
estimates

18. Grid Direct VS. battery-based systems
 Grid direct- requires anti islanding
 DOES NOT function when grid is down
 Net-metering/ dual metering potential
 Grid offers “free storage”
 More efficient than batteries
 Inverter selection

19.  Battery based / Battery back-up
 Stand Alone - will function when grid is down if storage exists
 Grid tied with Battery Back-up- Critical load panel will function
when grid is down-
 limited capacity depending on battery bank size (autonomy)
 More reliable = more storage = more expensive
 Inverter selection, additional components
 Conductors, OCPDs, charge controller, batteries, critical load
panel, extra inverter if AC Coupled (battery backup)
 NEC 690 Part VIII - Storage Batteries
 NEC 480 - Storage Batteries
Grid Direct VS. battery-based systems

20. Battery-based systems

21. Site Assessment: Layout & Install
 Component location
 NEC requirements
 Effects on performance and cost
2011 NEC

22. Component Location
& NEC Requirements
 Installed in neat and workmanlike manner - NEC
110.12
 Installed as listed or labeled - NEC 110.3(B)
 Spaces required - NEC 110.26
 Depends on location, voltage, etc.

23. Component Location
 MODULES:
 IFC regulations - becoming a standard
 Not mandated in 2012 NEC
 Look for it in 2014
 Attachments - framing considerations (roof)
 Shading - again and again

24. Inverter Location
 Inverter - Distance from load center
 Locate inverter near installation to avoid voltage drop
 Potential shut down (design for inverter voltage range)
 Prevent extra installation costs
 Power loss, reduced ROI
 Conductors
 Conduit runs
 Expansion fittings
 Design time
 Labor time
 Chosen to match electrical connection

25.  Component functionality/treatment:
 Out of sun
 Consider temperature
 Requirements for equipment installation
 NEC 110.13 - mounting and cooling
 NEC 110.12 - neat and workmanlike
 NEC 110.26 - working spaces
 NEC 110.27 - live parts
 Equipment manual - NEC 110.3(B)
 Installed as listed and labeled
Inverter Location

26. Component Selection / Location
Resources
 Resources:
 Voltage drop - #SolarMOOC with Raymer and Stovall
 String sizing: Jeff Gilbert #SolarMOOC
 Verifying System Design- voltage considerations, inverter
matching, string sizing

27. Component Selection / Location
 DC rated- NEC 690.4(D)
 Disconnects, OCPDs
 Disconnecting means- NEC 690 Part III
 DC disconnect must be in an accessible location
 AHJ may require additional external DC disconnect even if
integrated into Inverter
 AC modules/microinverters: NEC 690.6
 Batteries: NEC Article 480 & Article 690 Part VIII
 NEC 480.9: Battery locations (NEC 110)
 NEC 480.8: Racks and trays
 NEC 690.71(B): dwellings = <50V Nominal
 NEC 690.71(D): Nonconductive racks

28. Effects on Performance
and Cost
 Performance
 SHADE!- needs to be taken seriously- a tiny amount could kill
production, and ROI for customer
 Consider microinverters for potential solution
 Geographical site considerations for production-
smog, elevation, & Peak Sun Hours
 High temperatures effect voltage (lowers)
 High temperatures can effect equipment
 Costs
 Roof type and tilt or soil determines ease of installation
 Requirements of interconnection- may require electrical
upgrade

29. Equipment selection:
component matching
 Grid Direct Systems:
 Inverter to Voltage (string design of array)
 Match the inverter voltage window
 Start voltage
 Max of inverter as well as 600V DC limit per NEC code
 Consider MPPT range

30. Equipment selection:
component matching
 Grid Direct Systems:
 Inverter to Voltage (string design of array)
 Match the inverter voltage window
 Start voltage
 Max of inverter as well as 600V DC limit per NEC code
 Consider MPPT range
 Conductor chosen for ampacity and conditions
 Mike Holt- Verifying System Design

31. Other BOS components…
 Conduit and conductors chosen for conditions and NEC
requirements
 Ex.: NEC requires metal conduit for DC conductors run inside of
a building - NEC 690.31(E)
 Ex.: PV Source conductors must be USE-2 or PV wire- NEC
690.31(B)
 All equipment must be DC rated (unless dealing with AC
modules/microinverters)

32. Component Selection:
utility interconnection requirements
 Make sure panel is not overloaded
 NEC705.12(A) - Supply side connections possible
 Treated as service connections- reference to NEC 230
 NEC 705.12(D)(5) - Circuit breakers must be “suitable
for backfeed” - if marked line and load, not suitable for
load side connection

33. Component Selection:
utility interconnection requirements
 NEC 705.12(D) - Utility Interactive inverters
 NEC 705.12(D)(2) - load side connection- 120% rule allowed
 Sum of amp rating of OCPDs connected must not exceed 120%
of rating of busbar
 Ex. 200A bus bar x 1.2 = allowable 240A OCPDs
 240A - 170A = 70A
 170A in use, then max load side connection is 70A
 Exception - with battery bank- can use inverter output
current:
 Ex. 30A output from inverter = 30 x 1.25 = 37.5A, 40A OCPD

34. Component Selection:
utility interconnection requirements
 Resource:
 http://solarprofessional.com/articles/design-
installation/nec-section-70512-and-utility-
interconnections
 Google: Supply side connection PV, or search SolarPro

35. Component Selection:
utility interconnection requirements
 120% rule: #SolarMOOC w/ Richard Stovall,
SolPowerPeople CEO and IREC Certified Master
Trainer

36. A favorite resource

37. Who are we, and who am I?
 SolPowerPeople, Inc.
 IREC Accredited Continuing Education Provider
 Offering Solar Training, in person and online
 Sarah Raymer
 Director of Education and Training
 Asst. Instructor, #SolarMOOC host
 NABCEP Certified PV Installation Professional
 sraymer@solpowerpeople.com