Connecticut Solar Permit and Interconnection Requirements

Connecticut is one of the more workable states for solar installers once you understand how the pieces fit together. There is no single statewide solar permit, but Connecticut provides a standardized Solar PV Permit Application Supplement that gives installers and local building officials a uniform format for residential PV project information. Connecticut solar permit requirements run through your local building department, while a separate track handles Eversource or United Illuminating interconnection and the state's RRES tariff program.

Getting a Connecticut solar interconnection application approved on the first try means treating these as two parallel projects rather than one linear process. This guide walks through municipal permitting, contractor licensing, utility interconnection, and RRES program mechanics, including the rate changes that took effect for 2026 enrollees.

Need a Connecticut plan set built to these requirements from the start? GreenLancer provides Connecticut solar installers with permit-ready PV plan sets, structural and electrical engineering reviews, Connecticut PE stamps, and solar interconnection application support for Eversource, United Illuminating, and other utility territories.

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How the Connecticut solar permitting and interconnection process works

A Connecticut solar project generally moves through the same sequence regardless of the town or utility involved. Knowing this order ahead of time helps you set customer expectations and avoid scheduling gaps between steps.

• Confirm your municipality's building department requirements and any zoning or historic district triggers

• Prepare permit drawings and the Connecticut Solar PV Permit Application Supplement

• Submit the municipal building and electrical permit application

• Submit the utility interconnection application through Eversource's or United Illuminating's PowerClerk portal

• Receive contingent approval from the utility

• Install the system and schedule the municipal electrical inspection

• Submit passed inspection documentation to the utility for meter setup

• Receive final utility approval before energizing the system

The municipal and utility tracks can run at the same time in most cases. Some utilities want proof of a passed inspection before they will finalize interconnection, so confirm the sequencing your specific EDC expects before you commit to a customer timeline.

Connecticut solar permit requirements by municipality

Connecticut doesn't have one statewide solar permitting process. Building permits are issued and enforced locally, which means the checklist you use in Hartford might look slightly different from the one in a small shoreline town. The state building code sets the underlying rules, but each Authority Having Jurisdiction, or AHJ, decides how it wants documents submitted.

Building and electrical permits

Most Connecticut municipalities require both a building permit and an electrical permit for a residential PV system. Roof-mounted systems typically need a structural review addressing attachment method and roof load, along with an electrical permit covering wiring, overcurrent protection, and grounding. Ground-mounted and pole-mounted systems can also trigger zoning review, and sites near regulated wetlands or upland review areas may need Inland Wetlands Commission approval on top of the standard permits.

Connecticut Standardized Solar PV Permit Application Supplement

Connecticut's building officials worked with the Connecticut Green Bank to create a standardized Solar PV Permit Application Supplement, which many towns accept alongside the regular building permit application. It's a one-page technical information sheet that gives building officials a consistent format for reviewing PV system details, rather than a replacement for your municipal application.

This form doesn't remove local variation entirely, since every AHJ can still ask for its own additional attachments. It just gives you one consistent starting point instead of reinventing the submittal for every town. You can read more about the supplement's origin and intent directly from the Connecticut Department of Administrative Services.

What goes into the plan set

The supplement itself references a set of standard attachments. Reviewers expect these to be complete and consistent with each other, since mismatches between drawings are one of the most common causes of a redline. A typical Connecticut residential PV permit set includes:

• Cover sheet with project and contractor information

• Site plan showing array location, setbacks, and conduit routing

• Roof or array layout drawing with attachment and racking details

• Electrical one-line diagram showing service rating, point of interconnection, and conductor, raceway, and overcurrent protection sizing

• Rapid shutdown documentation

• Equipment specification sheets for modules, inverters, and racking

• Required labels and placards

• Attachment for roof-mounted systems or the separate attachment for pole and ground-mounted systems, but not both on the same submission

• Structural calculations or evaluation when required by the municipality, often as a PE-stamped worksheet

• Additional subcontractor list if more than one licensed trade is involved

Larger systems can also use the supplement, but a municipality may request extra information as an additional attachment. The Clean Energy States Alliance publishes a broader Connecticut rooftop solar permitting reference that ties these documentation requirements back to the specific building and electrical code sections behind them.

When a PE stamp or extra review applies

Structural review requirements vary by town and by roof condition. Older roofs, systems above a certain size, and any project where the building department has questions about load capacity are the most common triggers for a PE-stamped structural evaluation. Ground-mounted systems are more likely to need a stamped foundation design given the added wind and soil considerations.

Zoning, wetlands, and historic districts

Ground-mounted arrays can trigger zoning review for setbacks, height, and lot coverage, and sites near wetlands may need an additional Inland Wetlands Commission review. Projects located in a historic district often need a certificate of appropriateness before the town will issue a building permit, and whether visibility from the street matters depends on the specific district's rules, so confirm with the local commission rather than assuming. Our ground mount solar permit requirements guide breaks down the structural and site plan documentation these projects typically need.

Connecticut solar contractor licensing requirements

Connecticut licenses solar electrical work separately from general electrical work, and getting this wrong on a permit application is an easy way to trigger a rejection. The Department of Consumer Protection oversees these licenses, and the scope of each one is more specific than installers sometimes assume.

PV-1 and PV-2 licensing

A PV-1 Limited Solar Electric Contractor license covers the installation, repair, and maintenance of PV systems. A PV-2 Limited Solar Electric Journeyperson license allows someone to do that same work, but only while employed by a licensed electrical contractor. Both are limited licenses, and standard E-1 and E-2 unlimited electrical licenses also cover solar work, since they permit all electrical work under Connecticut law.

One detail worth knowing before you staff a job: neither a PV-1 nor a PV-2 license holder can connect wiring to an existing panel, junction box, wiring, or circuit on the property. The Electrical Work Examining Board has clarified that both licenses are limited to terminating wiring into their own junction box or controller, one that isn't tied into the building's existing electrical system or utility meter.

If your crew needs to tie into an existing panel, that step needs an E-1 or E-2 license holder instead. Full scope details are available from the Connecticut DCP electrical license types page.

Home Improvement Contractor registration

Residential solar work also falls under Connecticut's Home Improvement Contractor law, so most installers doing residential jobs need HIC registration in addition to their electrical license. Written home improvement contracts must include the contractor's HIC registration number, and this is one of the first things a building department or a customer's attorney will check if a dispute comes up later. The Connecticut DCP home improvement page outlines the registration requirements in more detail.

Where license numbers need to appear

• PV-1, PV-2, E-1, or E-2 license number on the electrical permit application

• HIC registration number on the written contract for residential jobs

• Subcontractor licensing information on the PV supplement's subcontractor attachment when multiple trades are involved

• PE stamp and license number on any structural evaluation the municipality requires

Connecticut solar interconnection: Eversource vs. United Illuminating

Connecticut has two investor-owned utilities handling interconnection, and each runs its own application process. Eversource covers most of the state, while United Illuminating serves the New Haven and Bridgeport shoreline area. The underlying PURA guidelines apply to both, but the portals and day-to-day handling differ.

Eversource PowerClerk application

Eversource processes Connecticut solar interconnection applications through its online PowerClerk system. You'll create an account, submit system specifications and a single-line diagram, and track the application through each stage from acknowledgment to final approval. Details on getting started are available on the Eversource Application to Connect page, and general interconnection guidance is on their Connecticut Renewable Energy Solutions interconnections page.

United Illuminating's process

United Illuminating also uses a PowerClerk Renewable Energy Solutions Portal for residential interconnection and RRES applications, separate from Eversource's PowerClerk instance. Although the two utilities run separate portals and project workflows, both operate under the same PURA-approved interconnection framework, so the underlying technical screening criteria are consistent between them.

	Eversource	United Illuminating
Application platform	PowerClerk	PowerClerk Renewable Energy Solutions Portal (separate instance)
RRES administrator	Eversource	United Illuminating
Final approval term	Approval to Interconnect	Approval to Operate
Production meter	Utility-owned, required for RRES	Utility-owned, required for RRES

Interconnection review timelines

For systems up to 25 kW AC, Connecticut's interconnection guidelines set a general sequence rather than one single deadline. The EDC typically acknowledges receipt of a complete application within a few business days, follows with a completeness review, and then moves into tariff compliance review before technical screening begins. Once tariff compliance is confirmed, the EDC works toward a contingent approval notification within 15 business days if the application passes screening.

That 15-business-day window applies after tariff compliance is confirmed, not from the moment you hit submit, so build a realistic buffer into your project timeline rather than counting exactly 15 days from application date. Full technical detail on this process is in the 25kW-or-Less interconnection guidelines.

Final approval before energizing

Systems cannot be turned on until the utility issues its final approval, called Approval to Interconnect at Eversource and Approval to Operate at United Illuminating. This step comes after the municipal electrical inspector signs off and, in most cases, after the utility completes any meter changes needed for the RRES tariff structure you selected. Our solar interconnection agreement guide walks through what happens between utility determination and final permission to operate in more detail.

Need help managing the paperwork on both tracks at once? GreenLancer's interconnection application service prepares application packages for Eversource and United Illuminating projects, helping installers keep system specifications, one-lines, equipment data, and utility forms consistent across the submission.

Connecticut RRES requirements for solar installers

The Residential Renewable Energy Solutions program, or RRES, is how Connecticut compensates residential solar owners for the power their systems produce. It replaced the state's older net metering structure in 2022, and installers need to understand its mechanics well enough to explain them clearly to customers. The PURA RRES program page is the authoritative source for current rules.

Who qualifies for RRES

RRES generally covers qualifying Class I renewable systems up to 25 kW AC based on inverter nameplate capacity, on one to four family residential properties. Certain qualifying multifamily affordable housing facilities with five or more units can also participate under separate program requirements. Larger projects and standard non-residential systems fall under a separate program, which we'll cover further down.

One eligibility detail worth flagging to customers early: homes built before January 1, 1980 generally need a completed or scheduled Home Energy Solutions or Home Energy Solutions Income Eligible assessment to qualify. Homes built on or after January 1, 1980 can waive this requirement with a property assessor's card confirming the build date.

Newer homes without a completed HES assessment can sometimes qualify through a DOE Home Energy Score or Weatherization Assistance Program documentation instead. If an assessment hasn't already been completed, it generally needs to be scheduled as part of the application process. Program scheduling or budget constraints that prevent completion don't necessarily stop application or interconnection approval, but the step still needs to be documented before or during application, not discovered after installation.

Netting Tariff vs. Buy-All Tariff

Customers choose between two compensation structures when they enroll, and the choice cannot be changed once selected. Under the Netting Tariff, the solar system powers the home first, and any excess exported to the grid earns credits at the applicable retail rate, rolling over month to month. Under the Buy-All Tariff, the utility purchases all the system's production at a fixed rate set for the enrollment year, and the homeowner keeps buying their regular electricity from the grid.

Netting tends to suit customers who want to offset their own usage and possibly add battery storage later. Buy-All appeals to customers who want a predictable, fixed payment and don't mind that the panels aren't directly reducing their bill.

	Netting	Buy-All
Solar serves home load first	Yes	No, production is exported and separately metered
Export compensation	Applicable retail rate, changes over time	Fixed tariff rate for the enrollment year
What's fixed for 20 years	REC incentive rate and Solar Energy Adjustment (Netting only), not the retail export rate	The full incentive payment rate
Production meter	Required, utility-owned	Required, utility-owned

2026 RRES rates and the Solar Energy Adjustment

RRES compensation terms are set annually for each enrollment year, but what stays fixed over the 20-year tariff term depends on which tariff a customer picked. The Buy-All incentive rate is locked in at enrollment and doesn't change. Under Netting, the retail export value moves with the customer's applicable retail rate over time, while the REC incentive rate and Solar Energy Adjustment assigned at enrollment stay fixed. For 2026 enrollees, the Buy-All tariff rate is $0.3289 per kWh, and Netting exports are credited at the applicable Standard Service retail rate rather than a fixed number.

A newer detail worth flagging to customers directly is the Solar Energy Adjustment, which Eversource calls the Solar Energy Adjustment and UI calls the Solar Production Charge. This applies specifically to Netting Tariff enrollees.

For 2026 Netting Tariff enrollees, it's a non-bypassable charge of $0.0402 per kWh applied to total production measured by the production meter, and it has increased substantially since it was introduced at a fraction of a cent. This charge is set for the project's enrollment year and stays fixed for the tariff term. Rates and adders change from year to year, so confirm current figures against the RRES Program Manual before quoting a customer's savings.

RRES also includes additional incentive adders for low-income customers and for projects in economically distressed municipalities, and a system can only receive one adder even if it qualifies for both. For 2026, the low-income adder is $0.055 per kWh on Buy-All and $0.035 per kWh on Netting, while the economically distressed municipality adder is $0.0275 per kWh on Buy-All and $0.0175 per kWh on Netting. These figures are set annually, so confirm current numbers before building a customer proposal.

System sizing rules

RRES systems generally can't be sized to expect more annual production than the customer's highest annual usage over any 12-month period in the past 5 years, plus a 5 percent margin. On top of that base, the program allows additional capacity for planned future electrification. Installers need to flag these planned additions in the application itself, along with an expected purchase timeline, not add them after the fact.

• Up to two electric vehicles, at an estimated 3,285 kWh per vehicle per year

• A whole-home air-source heat pump, estimated at 3,608 kWh per year

• A whole-home ground-source heat pump, estimated at 2,458 kWh per year

For homes with less than 12 months of usage history under the current occupant, or for new construction, systems can generally be sized up to 9 kW AC without relying on that usage history. Larger new-construction systems need an accepted energy model, such as Manual J or REM/Rate, submitted with the application. Oversizing beyond what these rules allow is a common reason interconnection approval gets held up, so it's worth double-checking the math before you submit.

Metering and customer disclosure

RRES projects need a utility-owned production meter for both Netting and Buy-All systems, and getting the meter configuration wrong is a common source of delay between installation and final approval. For 2026, Eversource meter fees run $183 for a standard Form 2S meter and $234 for a Form 12S network meter, while United Illuminating charges a flat $348 regardless of meter type. These fees are billed to the system owner and can change from year to year, so confirm current numbers with the customer's EDC before you finalize the electrical design.

Connecticut also requires a Customer Disclosure Form to be provided before the customer signs a solar contract, with separate versions depending on whether the customer owns the system directly or is entering a third-party ownership arrangement. Getting this signed and filed correctly protects both the installer and the homeowner if questions come up later about what was promised.

What's changing next

Connecticut passed a substantial renewable energy bill in 2026 that touches several of the state's clean energy tariff programs and, more directly relevant to your daily work, permitting itself. RRES rules described above remain in effect for active applications. See the law updates section further down for what's actually changing this year.

RRES mechanics change year to year, and getting a customer's savings numbers right matters for your close rate and your reputation. Reach out through the form below if you'd rather have your permit and interconnection paperwork handled by a team that tracks these updates for you.

Connecticut commercial solar and projects above 25 kW AC

Not every Connecticut solar project fits under RRES, and it's worth being clear with customers about which program actually applies to their job. Commercial and non-residential systems fall under the Non-Residential Renewable Energy Solutions program, or NRES, which has its own tariff structure, project caps, and application process separate from the residential rules described above.

• Systems above 25 kW AC generally fall outside RRES eligibility

• Commercial and light commercial projects apply under NRES rather than RRES

• Ground-mounted arrays on larger properties may need additional zoning and wetlands review regardless of program

• Projects that add battery storage may need updated interconnection documentation alongside the original solar application

If your project includes energy storage, our solar battery storage permits guide covers the fire department review and updated interconnection steps that typically come with adding an ESS to a PV system.

Who approves a solar project in Connecticut

Requirement	Authority
Building permit	Local municipality's building official
Electrical permit	Local municipality's electrical inspector
Zoning	Local land-use authority
Wetlands	Local Inland Wetlands agency, where applicable
Interconnection	Eversource or United Illuminating
RRES tariff	PURA framework, administered by Eversource and UI
Contractor licensing	Connecticut Department of Consumer Protection
Structural PE stamp	Licensed engineer, when required by the AHJ

Connecticut solar permit and interconnection checklist

Stage	What installers need
Municipal permit	Building and electrical permit applications, PV Supplement, one-line electrical drawing, one-line site plan, structural evaluation if required
Contractor documentation	PV-1, PV-2, E-1, or E-2 license number, HIC registration for residential contracts
Utility interconnection	PowerClerk or UI application, system specifications, single-line diagram, tariff selection
RRES enrollment	Customer Disclosure Form, sizing documentation, tariff payment beneficiary information
Closeout	Passed municipal inspection, meter configuration confirmed, final utility approval before energizing

Common Connecticut solar permit and interconnection delays

These issues frequently lead to corrections, resubmittals, or delays on Connecticut solar projects. Building these checks into your internal quality process before submission saves real time on the back end.

• One-line electrical drawing doesn't match the utility interconnection application

• AC nameplate capacity is inconsistent between the permit set and the interconnection paperwork

• Proposed system size exceeds what RRES sizing rules allow for the customer's usage history

• Planned EV charger or heat pump load wasn't documented to support an oversized system

• Contractor license or HIC registration number missing or incorrect on the application

• Production meter configuration doesn't match what the utility expects

• Customer Disclosure Form incomplete or missing before the contract was signed

• Ground mount project didn't account for zoning or wetlands review timing

2026 Connecticut solar law updates

A smart solar permitting platform is coming, but not until 2028

This is probably the most directly relevant permitting change for installers, even though it's not immediate. Public Act 26-127 directs the Department of Administrative Services to implement a statewide automated smart solar permitting platform, similar in concept to SolarAPP+, by July 1, 2028. Municipalities then have until January 1, 2029 to accept applications through that state platform or an equivalent automated system of their own. The platform is meant to instantly review and issue building permits for qualifying residential solar and solar-plus-storage systems up to 25 kW. It's a real shift in direction, but it's a multi-year rollout, not something that changes your permit process this year.

Plug-in and balcony solar

Starting October 1, 2026, Connecticut will allow qualifying portable plug-in solar devices up to 1,200 watts without requiring the customer to get utility approval or enter into a traditional interconnection agreement. Utilities also can't charge a device-specific fee or require added controls beyond what's built into qualifying, UL-certified equipment. What the law doesn't do is exempt these devices from the State Building Code, Fire Safety Code, or local ordinances, so a local permit or other approval may still apply depending on the installation.

This applies to small portable or balcony-style systems rather than standard rooftop installations, and it doesn't change permitting requirements for conventional PV systems your crews are installing. It's still worth knowing about, since customers may ask whether it affects their existing or planned project, and worth clarifying that "no utility approval needed" isn't the same as "no permit needed."

Proceedings to watch

Public Act 26-127 directs PURA to develop successor programs for RRES, NRES, and the state's shared clean energy facility program more broadly. Among the specific proceedings the law requires is an August 1, 2026 deadline for PURA to initiate a proceeding establishing a successor to the Non-Residential Renewable Energy Solutions program, alongside a new Community Solar Program succeeding the shared clean energy facility program.

Installers should keep using the current RRES rules for residential projects while watching these proceedings, since program terms for other parts of the state's clean energy portfolio are shifting this year. Read the enacted language directly in Public Act 26-127.

How GreenLancer supports Connecticut solar installers

GreenLancer helps Connecticut solar contractors prepare permit and interconnection packages for residential, commercial, ground-mount, and solar-plus-storage projects. Services include permit-ready solar plan sets, structural and electrical engineering reviews, Connecticut PE stamps, and utility interconnection application support.

Connecticut solar permit plan sets

GreenLancer prepares permit-ready PV plan sets based on the project address, AHJ requirements, equipment, and site conditions. Packages can include site plans, array layouts, structural details, single-line diagrams, NEC calculations, equipment specifications, placards, and ESS documentation when applicable.

Connecticut solar engineering reviews and PE stamps

When the AHJ requires sealed documentation, GreenLancer provides structural and electrical engineering reviews through engineers licensed in Connecticut. Deliverables may include PE-stamped drawings, structural calculations, attachment reviews, foundation engineering, or electrical engineering based on project requirements.

Connecticut solar interconnection applications

GreenLancer provides solar interconnection application support for projects served by Eversource, United Illuminating, and other Connecticut utility territories. Services can include application preparation, supporting drawings, equipment documentation, and coordination between the interconnection package and permit plan set.

Complete the form below to get your next Connecticut project started.

FAQs on CT Solar Permitting, Engineering, and Interconnection

Does Connecticut have a statewide solar permit?

No. Solar permits are issued and enforced locally by each municipality's building department. Connecticut does provide a standardized Solar PV Permit Application Supplement that installers can submit alongside the local building permit application to give reviewers a consistent format.

What is the Connecticut Solar PV Permit Application Supplement?

It's a one-page technical information sheet developed by the Connecticut Green Bank, the CT Building Officials' Association, and the Office of the State Building Inspector. It standardizes how installers report system details for residential roof and ground-mounted PV projects, but it supplements rather than replaces your municipal permit application.

Does a solar installer need a Connecticut license?

Yes. Solar electrical work requires a PV-1, PV-2, E-1, or E-2 license depending on the role, and residential jobs also require Home Improvement Contractor registration. A PV-2 license holder can only work under a licensed electrical contractor and cannot connect to an existing panel or circuit.

How long does solar interconnection take in Connecticut?

For systems up to 25 kW AC, utilities generally work toward a contingent approval notification within 15 business days once an application clears tariff compliance and technical screening. Total timeline varies based on application completeness and any additional review needed for the specific site.

What's the difference between Eversource and UI solar interconnection?

Both utilities use PowerClerk, but through separate instances with different portals and workflows, and both follow the same PURA interconnection guidelines. Technical screening criteria are consistent across both, since they operate under the same regulatory framework.

What's the difference between the RRES Netting and Buy-All tariffs?

Netting credits excess solar production against the customer's own usage at the retail rate, with credits rolling over monthly. Buy-All has the utility purchase all production at a fixed rate set for the enrollment year, separate from the customer's regular electric bill.

What are Connecticut's 2026 RRES solar rates?

For 2026 enrollees, the Buy-All tariff rate is $0.3289 per kWh, and Netting exports are credited at the applicable retail rate. For 2026 Netting Tariff enrollees specifically, a $0.0402 per kWh Solar Energy Adjustment or Solar Production Charge also applies to total metered solar production. These figures reset annually, so confirm current rates before quoting a project.

How large can a residential system be under Connecticut RRES?

RRES covers qualified residential systems up to 25 kW AC. Sizing is generally tied to the customer's historical usage, with additional allowances available for planned electric vehicles or a fuel-switch appliance like a heat pump.

When does a Connecticut solar project need a PE stamp?

Requirements vary by municipality, but structural evaluations are more commonly required for older roofs, larger systems, and ground-mounted arrays. Check with the local building department early, since a required PE stamp affects both your timeline and your proposal.

Can Connecticut HOAs restrict solar panels?

Connecticut law generally prevents common interest community associations from adopting rules that outright prohibit unit owners from installing solar on their roofs, though associations may still have some ability to regulate placement and appearance. Review the specific association's governing documents before finalizing a design in an HOA community.

Does GreenLancer provide Connecticut solar permit plans and interconnection services?

Yes. GreenLancer provides solar installers with Connecticut PV permit plan sets, electrical and structural engineering, PE stamps when required, and utility interconnection application support for Eversource and United Illuminating projects.