Home Battery Storage Permit Requirements in Connecticut (2025)
Last updated: June 2025
Connecticut Bottom Line: A permit is required in all Connecticut municipalities. CT has a state building code with local enforcement. Typical fees: $225–$475. Eversource serves most of CT and has a residential storage interconnection process (3–5 weeks). CT adopted the 2020 NEC. Review time: 1–3 weeks.
How Connecticut Battery Permits Work
Connecticut has the Connecticut State Building Code enforced by local building officials. Every town requires permits for residential battery storage. Connecticut adopted the 2020 NEC in 2023. The state requires licensed electrical contractors for all permitted electrical work through the CT Department of Consumer Protection.
The Permit Process
CT towns vary significantly in size and permitting capacity. Hartford, New Haven, Bridgeport, and Stamford have online permit portals with 1–2 week review times. Smaller CT towns may use paper-based systems with 2–3 week review times. Eversource CT's residential interconnection application takes 3–5 weeks.
Documents Required
Required: permit application, single-line diagram, UL 9540 spec sheets, Connecticut DCP-licensed electrical contractor, site plan. Some CT towns require a homeowner affidavit for owner-occupied properties.
Permit application from your local building department
Single-line electrical diagram — your installer prepares this
Equipment spec sheets showing UL 9540 listing
Licensed contractor license number
Site plan showing battery location relative to the panel
Frequently Asked Questions
In virtually all incorporated areas of Connecticut, yes. A residential battery storage system requires an electrical permit wherever the NEC has been adopted. Always verify with your local building department before proceeding without one.
Typical review times range from 5 to 21 business days depending on your city. Smaller cities with online portals tend to be faster. Your installer can give you a current estimate based on recent project experience in your jurisdiction.
Most reputable installers handle permit filing as part of the installation package. Confirm this before signing a contract and request the permit number once it's issued so you have documentation for your records.
Informational only — not legal or electrical advice. Verify requirements with your local building department before starting any project.