1. Initial Preparation

● Open the Add-On account and gather all standard design documents.

● Locate and open the original account in Salesforce.

● Open the original plan set.

● If the original design is less than a year old, review the original survey photos for additional context.


Verify Ownership of the Existing System

If the existing solar system is NOT owned by ION, Vision, or Zing, the Add-On design cannot proceed without executive approval. In this situation:

1. The project must be sent to Electrical Review for system disqualification.
   
   

2. If executive approval is granted, the account will be returned under your name, and you may move forward with the Add-On design as normal.
   
   

3. However, if a signed “Waiver and Release Add-On” document is found in the contract folder with the CIA, then you may proceed with the design—even if the existing system is owned by another company.

2. Design Tool: Data Collection

● Proceed with standard data collection in the design tool.

● Enter all required inputs up to the electrical section.

3. Electrical Section: Existing System Review

● Reference the original plan set to identify the existing interconnection method.

● Cross-check with new survey photos to verify accuracy and ensure existing conditions match documentation.

4. Plan the New Interconnection

● Design the new interconnection based on the existing sy

You may combine the new system into the existing combiner box if:

● There is physical space for new circuits.

● The existing combiner is a Combiner 4 or higher.
○ ⚠️ Note: Combiner 3s do not support IQ8 breakers.

● Upsize all wires, AC disconnects, and PV meters as required to accommodate the combined systems.

5. Electrical Notes

● Write a clear and complete electrical note:
○ Start with details about the existing system.
○ Follow up with the new interconnection details, including any additional equipment and placement.
○ Always include the total combined backfeed of both systems.
○ 🔧 Installer Note: Include a note to update the combiner to ensure inverter compatibility.

6. Solargraf Layout

● Read and understand all applicable jurisdiction requirements before beginning layout.

● Build the house model and layout:
○ Represent the existing system using flat rectangular obstructions.
○ Design the new array layout.
○ Include both existing and new modules when calculating roof coverage.
○ Existing modules may be placed inside fire setbacks.
○ Always seek approval before dropping panels.

7. Racking Calculator & Jurisdiction Review

● Complete the racking calculator in the design tool.

● Reconfirm all jurisdiction requirements and address as much as possible before moving to the plan set.

8. Notes & Bill of Materials (BOM)

● Finalize all necessary design notes:

○ Layout
○ Electrical
○ Structural
○ Site notes

● Review the Bill of Materials:

○ Use the Senior Design Cheat Sheet to determine if additional materials (breakers, conduit, etc.) are required.
○ Additional materials may not be needed for every Add-On—use discretion.

9. Electrical Calculations Page

● Navigate to the electrical calc page in the design tool:

○ Add the existing system’s panel type beside the new system’s panel type.
○ Input the correct electrical specifications for the existing panels beneath the new entries.

Microinverter Adjustments

● Copy applicable data from the new system’s section.

● Adjust formulas and cell references as needed for the existing system.

● Validate final outputs:
○ Refer to the Add-On Reference Design—highlighted cells show what needs to be updated.
○ Ensure the DC/AC system size reflects only the new system on the input page.

10. AutoCAD: Import and Plan Set Preparation

● In the AutoCAD Import tab:
○ Select all relevant electrical details for the new system and prefix them with (N).
○ Refer to the Add-On Reference Tool for what needs to be updated—highlighted sections help guide you.

● Begin the plan set in AutoCAD:
○ Model the roof and apply a distinct hatch pattern to the existing system.
○ Label clearly: “EXISTING SYSTEMS PANELS (TYP.)”

● Create the One-Line Diagram:
○ Show both new and existing system interconnections.
○ Label new components as (N) and existing components as (E).
○ Beneath each existing circuit, include panel and microinverter specs, just like you do for the new system.

11. Final Plan Set Adjustments G-1 Sheet

● Use the reference design for formatting guidance.

● Move the sheet list below the jurisdiction blocks.

● Paste the new system block in the original sheet list location.
○ Convert this block into the existing system block with SEC, CEC, etc.
○ Add a third section below for combined system totals.

12. Site and Roof Plan Pages

● Proceed as you would with a standard system design.

● No further changes beyond what’s already covered are required.

13. Electrical Calc Page (E-7)

● Move the existing calc section off the page.

● From the design tool:
○ Highlight the updated electrical calc page.
○ Insert it into AutoCAD using the link input feature.
○ This ensures live updates carry over to the plan set automatically.

14. Final Quality Check

● Review all pages, notes, and diagrams thoroughly.

● Ensure all AHJ requirements are met.

● Confirm all labeling, equipment callouts, and modeling are accurate and complete.

✅ Completion Once everything has been completed and reviewed for accuracy and compliance, your Add-On design is officially finished.

Great work—and congratulations!