THE SHORT ANSWER
OUC’s published contractor sequence begins by sending the service address and proposed system size or one-line diagram for transformer-upgrade review, before permits, installation, inspection and the final interconnection application. [1]
Start with a defined proposal
The review needs more than a homeowner’s target offset. Record the service address, array DC size, inverter configuration and any storage shown on the preliminary one-line. Ask who sent the request and when; otherwise “submitted to OUC” can become an untraceable project status.
Treat the result as design-specific
If module count, inverter output or service equipment changes, ask whether the transformer review must be refreshed. A response tied to an earlier system should not be reused without confirmation. Keep the dated drawing and OUC correspondence in the same folder so the assumptions remain visible.
Do not merge the utility and permit reviews
OUC distribution review, the local building permit and OUC interconnection approval are separate decisions. The utility’s early response does not approve roof attachments or code compliance. Conversely, a passed city or county inspection does not settle every utility capacity question.
Make any upgrade a written dependency
If OUC identifies work, request the responsible party, required documents and project dependency in writing. Do not promise cost or activation timing from a generic example. Ask whether an alternative design would change the finding and obtain a new review for any option you seriously consider.
Carry the same design to completion
Before installation, compare the permit set, contract exhibit and transformer-review drawing. After inspection, use the matching one-line in the interconnection package. Origin Direct can help control the proposal revisions, but OUC and the jurisdiction remain responsible for their approvals.
Before your next conversation
- Record who requested the OUC transformer review.
- Tie the result to a dated system size and one-line.
- Refresh the review after a material design change.
Primary sources
- OUC: Rooftop Solar and TruNet FAQs
Primary reference checked September 9, 2026. Confirm current requirements with the named utility, manufacturer or authority for your property.
Planning examples and questions are Origin’s editorial guidance, not a property-specific diagnosis, engineering design, tax determination or promise of savings. Manufacturer and utility references do not imply an affiliation with Origin.
Make the decision specific to your home.
Ask Origin to reconcile the OUC response with the final permit-ready design.
Book an Origin Direct review →Scope, pricing and availability are confirmed for your property. A consultation does not establish utility or incentive approval.