AE 868
Commercial Solar Electric Systems

PV System Electrical Design Project


Design Project Description

Our Design Project will span Lessons 8 and 9. The purpose of this project is to build the electrical technical skills needed for solar designers. These advanced skills help system designers prepare the permitting documents required by the utility reviewers as well as the actual construction document needed for installation.

Given the same 10kW system we discussed in previous Lesson Activities and after choosing PV module and inverter from the research paper you submitted ( you may also design a new 10kW PV system with any modules and inverter of your choice), now you need to prepare the one-line diagram for the PV system that contains the following:

  • Conductors / wires ampacity rating

  • Over-current protection device (OCPD) and disconnecting means (AC and DC disconnects) rating and sizing
  • Voltage Drop (VD) calculation based on 100 ft distance between PV array and Main Distribution Panel (MDP)

  • Interconnection requirements and methods for the following three scenarios:

    1. MDP rating is 100A and the main breaker is 100A (meter enclosed within MDP in All-in-one unit)

    2. MDP rating is 150A and the main breaker is 125A (meter enclosed within MDP in All-in-one unit)

    3. MDP rating is 100A and the main breaker is 100A (meter and MDP are two separate devices connected with a conduit)

Project Resources:

  • Electrical one-line diagrams are usually developed in the solar industry using the AutoCAD environment. However, for the purpose of this class, if you do not have access to AutoCAD, please use this Electrical Symbols for PV Project PowerPoint file with the electrical symbols as a reference. The symbols provided are labeled individually to describe their function. You can drag the symbol and drop it in the correct location to make connections between different symbols using lines that represent electrical conductors.
  • Review the Solar ABCs Expedited Permit Process Report - Revision 2 (also posted as a Recommended Reading on the Overview page) to help you with this project.
  • Here is an example of a PV sysetm drawings with the requirements. 


Students are expected to deliver the following:

  • A report showing all detailed calculations and the interconnection methods.
  • A one-line electrical diagram.

Formatting Requirements

  • The Report:
    • Two pages - double-spaced, 12 point font in PDF format
    • PDF dimensions must be set to 8.5 x 11
  • The One-line Diagram:
    • As mentioned above, the one-line diagram should be developed using any computer software (such as AutoCad or the symbols from the PPT file) and then attached as a PDF
    • PDF dimensions must be set to 11 x 17
    • Make sure to keep all text and symbols inside the page limits before you print the PDF version of the drawing
  • Title your Project "PV Electrical Design Project."
  • Please use the following naming convention: Last Name_First Name Design Project.PDF

Submission Instructions

You will work on the Report in Lessons 8 and 9. The Report will be submitted at the end of Lesson 9.

Submit your Report and Diagram to Lesson 9: PV System Electrical Design Project in Canvas.

Grading Rubric - Design Project

Below are the criteria on which your Design Project will be evaluated by the instructor.

PV System Electrical Design Project Grading Criteria
Criteria (Standards) Total Points Possible (10)
Design Project

The project introduces the reader to the sizing and calculations of the electrical components of the PV system. The report must address the conductor ampacity calculations, OCPD calculations, VD calculations, interconnection methods, and the one-line electrical diagram. The report must demonstrate understanding of the main design concepts explored throughout the course.
One-line Diagram:
  • One-line Diagram shows:
    • systems size and all components used
    • components sizes and ratings
    • related warning signs and labels
    • notes related to calculation or electrical connections on the diagram
Follows all assigned formatting requirements. 1
Report is well-written, edited, and properly cited. The report should show where the calculations come from according to the NEC articles. 1

Have questions?

Visit the General Questions and Discussion Forum in Canvas to discuss questions you may have for your Design Project. If you have a question about your project that you do not wish to share with the class, you can also email the instructor at any time.