Home › Utilities › Connecticut › UI (United Illuminating)

Investor-owned utility

UI (United Illuminating) interconnection application

UI (United Illuminating) is an investor-owned utility serving 314,909 residential customers in Connecticut (EIA-861, 2025). Gridpol files UI (United Illuminating) interconnection applications for licensed installers – solar, storage and EV chargers – with single-line diagram and site plan, unlimited for $500 a month.

Get started Look up another ZIP

Partly researched from official sources. verify on first project: uinet.com timed out again on 2026-11-13 (/w/application-process, /w/distributed-generation); data still only from 2017 joint Eversource/UI CT guidelines. Confirm UI portal (likely PowerClerk) and URL, current residential kW limit, document list, fees, storage rules and RRES tariff on uinet.com. Archive.org is not reachable from our fetch tool and web search budget was exhausted on 2026-11-13.

UI (United Illuminating) at a glance

Utility

United Illuminating Co (Avangrid (Iberdrola))

Type

Investor-owned utility

EIA utility ID

19497

Residential customers

314,909 (EIA-861, 2025)

Net-metered residential customers

27,647 (EIA-861, 2025)

Service territory

2 counties in Connecticut

Who submits

Not confirmed from UI pages (uinet.com unreachable during research). Under the joint Eversource/UI CT guidelines the Customer submits the application with payment; installers commonly act for the customer.

Export compensation

Net billing – Residential Renewable Energy Solutions (RRES) - Netting or Buy-All
CT statewide RRES program (PURA); UI-specific tariff not reviewed.

Review time (official)

Joint CT guidelines (Eversource & UI): receipt 3 BD, completeness 10 BD, contingent approval 15 BD after complete application, witness test request within 10 BD of inspector approval.

Documents UI (United Illuminating) asks for

Interconnection application formSigned residential interconnection application (joint CT guidelines) Gridpol prepares this.
Single-line diagram (one-line) (when applicable)Not confirmed for UI Gridpol prepares this.
Final inspection sign-offMunicipal electrical inspector approval (joint guidelines 2.7)

How the UI (United Illuminating) process runs

Utility acknowledges receipt (3 business days) and checks completeness (10 business days); incomplete applications are put on hold and may be deemed withdrawn if missing items are not supplied within 15 business days.
Utility runs screens and issues Contingent Approval to interconnect (good-faith target 15 business days after complete application).
Install system; obtain municipal electrical inspector approval.
Utility may request commissioning/witness test within 10 business days of receiving inspector approval and schedules meter replacement/installation.
Utility issues Authorization to Interconnect (PTO); do not operate before.

Fees

Fee	Applies to	Note
$200	Residential certified inverter-based (joint 2017 guideline: <=20 kW)	Current UI fee not confirmed

Utility fees are paid by the installer or customer; they are not part of the Gridpol plan.

Size levels and limits

Level	Up to	Note

Joint guideline 2017 covered <=20 kW; later revisions raised the residential threshold (25 kW / possibly 50 kW). Not confirmed for UI.

Common issues the utility lists

Missing/incomplete material at completeness review -> application placed on hold; withdrawn if not cured within 15 business days (joint CT residential guidelines 2.3)

Gridpol’s pre-submission check covers these before we file.

Sources

Eversource/UI joint Guidelines for Interconnection of Residential Single Phase Certified Inverter-Based Generating Facilities (Docket 03-01-15RE03, May 2017): https://www.eversource.com/Content/docs/default-source/ct---pdfs/guidelines-residential-interconnection.pdf?sfvrsn=2 (retrieved 2026-11-13)

Connecticut interconnection rule

Commission

Connecticut Public Utilities Regulatory Authority (PURA)

Interconnection rule

PURA-approved EDC Guidelines: Docket 17-12-03 RE06 'Guidelines for Generator Interconnection - Fast Track and Study Processes' (Eversource/UI, 2023-12-20) and Docket 03-01-15 RE04 'Guidelines for the Interconnection of Residential Single Phase Certified Inverter-Based Generating Facilities' (<=25/50 kW) – Guidelines for Generator Interconnection · source

Applies to

The two electric distribution companies: Eversource (CL&P) and United Illuminating; not municipal utilities (CMEEC members)

Application form

Joint EDC interconnection request submitted through each EDC's online portal (Eversource PowerClerk); separate simplified residential inverter guideline application

Timelines

Fast Track/Study guideline: receipt confirmation 3 business days, completeness notice 10 business days, applicant 15 business days to cure; generator signs agreement within 30 business days; EDC witness test within 10 business days of request.

Fees

$200 inverter-based <=25 kW; $500 Fast Track; $1,000 Study + actual study costs (Table 1 of guideline; Eversource CT page).

Insurance

General liability per guideline Table 2: <100 kW $300,000; >100 kW-1 MW $1,000,000; >1-5 MW $2,000,000; >5 MW $5,000,000; Eversource page lists N/A for inverter-based 0-25 kW but asks proof of insurance in residential application.

External disconnect

Eversource CT: isolation device (AC disconnect) must be visible and within 10 feet of main utility panel/meter; variance needs written approval.

Export compensation

Net billing – CGS 16-244z (Residential and Non-Residential Renewable Energy Solutions programs); legacy net metering CGS 16-243h
Traditional net metering closed to new residential customers end of 2021; RRES offers netting or buy-all tariff at fixed rates for the program term; NRES for non-residential. Program-year details not verified here.

Not bound by the rule

Municipal electric utilities (CMEEC members, e.g. Norwich, Groton, Wallingford) are not under the PURA EDC guidelines and set their own interconnection/net metering policies.

Guidelines for Generator Interconnection Fast Track and Study Processes, Docket 17-12-03 RE06: https://www.eversource.com/Content/docs/default-source/ct---pdfs/guidelines-generator-inter-fast-track.pdf (retrieved 2026-11-13)
Eversource CT - Application to Connect: https://www.eversource.com/residential/about/doing-business-with-us/interconnections/connecticut/connecticut-application-to-connect (retrieved 2026-11-13)
PURA Distributed Generation Policy Working Group: https://portal.ct.gov/PURA/Electric/Interconnection-Policy-Working-Group (retrieved 2026-11-13)

Other utilities in Connecticut

All Connecticut utilities →

Gridpol Unlimited

$500 / month

Unlimited interconnection applications. 12-month agreement, signed online. The agreement starts the day you sign; first invoice right away, then monthly.

Unlimited interconnection applications
Single-line diagram and site plan for every application
Pre-submission check against the utility’s requirements
Homeowner e-signature link for the authorization
Filing in your utility portal accounts or by the utility’s method
Utility questions, corrections and resubmissions
Follow-up through approval, inspection and PTO
Customer list, exports, API and webhooks

Get started

Applications are typically submitted within 2 business days after complete documents. Utility review times are set by each utility.