Your local permitting office will have requirements for how your battery system should be installed. Your installer is responsible for reaching out to them and securing the necessary permits. Because battery systems are relatively new, some local permitting jurisdictions may not have updated their code requirements to include residential battery storage. If there are hurdles along the way, your installer should help navigate through this process.
Some utilities may require interconnection review and approval for battery systems in addition to permitting by the local jurisdiction. Interconnection is the approval process you go through to connect an electrical resource to the electric grid. It is unclear whether utilities will require this step for systems used for battery backup purposes only when the grid is out. This is because residential battery systems are still relatively uncommon and can be used for many different things. This includes providing services to the grid while the grid is working. You can work with your installer to identify your utility’s requirements.