Getting permits approved isn't the same as being cleared to turn your system on — interconnection is a separate process with your utility specifically.
Interconnection is separate from building permits
Local building and electrical permits confirm your installation meets code; interconnection approval is your utility's separate process confirming your system can safely connect to the grid and be enrolled in net metering. Both are typically required, and they proceed somewhat independently, sometimes with a specific required order.
What the utility is actually checking
Interconnection review typically confirms system size relative to your service, appropriate safety equipment (like an automatic disconnect), and compliance with the utility's specific technical requirements — this is where net metering enrollment officially happens, not just at system installation.
Typical timeline varies significantly
Interconnection approval can take anywhere from a couple weeks to a couple months depending on your utility's process, current application volume, and system complexity — significantly variable, so build buffer time into your project timeline expectations rather than assuming your installer's estimate is guaranteed.
Permission to Operate (PTO) is the final green light
Even after physical installation is complete, most utilities require a final "Permission to Operate" confirmation before you can legally turn the system on and start generating — turning a system on before PTO in areas that require it can violate your interconnection agreement, so confirm this specific step with your installer.
Larger or unusual systems may face more scrutiny
A system size that's unusual for your area, or one combined with battery storage in ways that require additional review, can extend the interconnection timeline beyond a standard residential system — ask your installer if your specific project falls into a category likely to need extra review.
Frequently asked questions
Can I turn on my solar system before interconnection approval?
In most areas, no — operating before official Permission to Operate can violate your interconnection agreement and utility rules, even if the system passed local building inspection; check your specific utility's requirements.
Why does interconnection sometimes take longer than the installation itself?
Utility review queues, application volume, and the specific technical review required can all extend interconnection timelines well beyond the days it takes to physically install panels — it's a separate administrative process, not tied to installation speed.