How to Submit a Solar Interconnection Application: A Practical Guide
Every grid-tied solar system needs utility approval before it can operate. The interconnection application is how you get it. Most utilities follow a version of the IEEE 1547 / IREC model, but the details — forms, required drawings, supporting documents, and review timelines — vary by utility territory.
The core package typically includes four elements. First, a completed application form with the customer, installer, and system details filled in exactly as the utility's format requires. Second, a single-line diagram showing the point of interconnection, the meter, the main disconnect, the inverter, and the AC protection devices. Third, equipment specification sheets — also called cut sheets — for the inverter and, where applicable, the battery system. Fourth, a site plan showing the array location relative to the service entrance and meter.
Where applications get rejected: mismatched data. If the inverter model on the application form does not exactly match the model on the cut sheet or the SLD, the utility flags it. If the system size in kW on the form does not match the nameplate on the cut sheet multiplied by the module count, the utility flags it. Consistency across every document is the single most important success factor.
Timing matters. Most utilities quote 15 to 20 business days for Level 1 interconnection review (systems under 25 kW). Larger systems trigger supplemental review or impact studies with longer timelines. Submitting an incomplete package does not start the clock — it restarts it when you resubmit.
Utilities increasingly accept digital submissions through portals. Know which portal your utility uses. Uploading a 50 MB plan set as a single PDF when the portal has a 10 MB file limit is a preventable failure. Compress drawings, split files where required, and name them according to the utility's conventions.
The bottom line: an interconnection package is a compliance exercise. Match every field to every document, submit in the utility's preferred format, and treat the 15-day clock as something you earn by getting the first submission right.