Utility Interconnection Process: What Contractors Need to Know
Utility interconnection approval is separate from building permits and often takes longer. Understanding the process for major utilities—particularly California's IOUs—is essential for setting realistic project timelines and avoiding costly delays.
Major California Utilities
PG&E (Pacific Gas & Electric)
Submit via PG&E online portal. Include SLD, equipment specs, site plan. Pay $145 application fee. Timeline: 3–6 weeks residential, 8–12 weeks commercial.
SCE (Southern California Edison)
Submit via SCE interconnection portal. Fast track available for systems ≤ 30 kW (2–3 weeks). Standard review: 4–8 weeks residential, 10–16 weeks commercial/storage.
SDG&E (San Diego Gas & Electric)
Submit via Blue Sky portal. Often requires meter socket adapter ($150–300 hardware). Timeline: 3–5 weeks residential, 6–10 weeks commercial.
Pro Tip: Start the interconnection application as soon as building permit is submitted — don't wait for approval. Parallel processing can save weeks.
Common Rejection Reasons
| Issue | % of Rejections |
|---|---|
| Incomplete single-line diagram | 38% |
| Non-compliant inverter (not UL 1741-SA) | 22% |
| Missing homeowner signature | 18% |
| Incorrect NEM tariff selected | 12% |
| Panel rating issues (120% rule) | 10% |
NEM 3.0 (California)
New California interconnections since April 2023 use NEM 3.0. Export rates vary by time of day and are typically lower than NEM 2.0. Battery storage is now highly incentivized to maximize economics.
How EnersolConnect Handles Interconnection
We manage the complete process: application preparation, SLD, equipment specs, submission, tracking, and PTO coordination for PG&E, SCE, SDG&E, and 100+ utilities nationwide.