United Illuminating solar interconnection reviewers bounce a PowerClerk file when the one-line ignores UI’s own samples: missing meter, missing AC disconnect, no title block, or a three-phase service drawn as a cartoon. UI tells you what a complete package is. The application-process page is a list, not a suggestion. If you submit a municipal supplement PDF and no UI one-line, you have not applied to interconnect.
UI territory is not “the other Connecticut utility.” Meter sequences, portal attachments, and sample symbols are UI-specific. Athol Energy files UI jobs on the same interconnection desk as Eversource, with UI’s checklist, not a relabeled CL&P sheet. New Haven and Bridgeport municipal notes stay on the AHJ set.
United Illuminating solar interconnection drawings UI will actually screen
UI’s application-process page says a complete interconnection package includes a complete signed and dated application, processing fees, a one-line electrical schematic, a site plan, and technical specification documents. Fast Track and Study also need proof of insurance and evidence of site control. Residential 25 kW certified inverter-based, single-phase, uses the Guidelines for Interconnection of Residential Single Phase Certified Inverter-Based Generating Facilities of 25 kW(ac) or Less, plus the signed 25 kW or less interconnection application inside the PowerClerk package. If you are over 25 kW AC on a house, you are not on that guideline. You are in Fast Track territory and likely out of RRES.
One-line content UI has called out in developer guidance: service voltage, main-panel fuse or breaker, inverter make/model/rating, utility meter, isolation or AC disconnect, transformer and site structures as applicable, IEEE-style symbols. Identify the disconnect location relative to the meter, especially if it is more than 10 feet away. Title block: customer name, account or site identifier, and address. If existing DG is on site, show it and say so in the application. Hidden legacy arrays are how screens fail.
Use UI’s samples as a punch list. Central inverter residential sample versus microinverter sample are different drawings. If you are installing micros, do not submit the central-inverter sample with the inverter count changed in marker. Non-residential samples exist; C&I should start there, then add NRES metering.
Site plan: UI links a residential sample. Show the building, array, meter, disconnect, and access. If UI requires outdoor, grouped meters on a job that currently has an indoor meter, draw the proposed location. NRES webinars have told developers that indoor utility meters get relocated outside near the production meter and the utility disconnect. Even some residential comments follow that habit. Put the proposed location on the plan instead of arguing from a basement photo.
PowerClerk attachments and the signed application
UI’s developer guide for the DG portal (older 20 kW form language still circulates in the PDF) walks through inverter entry, total AC nameplate auto-sum, existing DG, and the upload section. Current residential RRES filing is PowerClerk. Anything marked required must be filled or the application is not complete. Attach signed application, agent authorization, site plan, electrical drawings, technical specifications, and other required documents under the correct category. “Other” is not a junk drawer for the one-line. Put electrical drawings in the electrical slot.
First UI project of the year may need the installer-customer contract upload. UI’s RES interconnection page lists that among forms required for all applications, with the 25 kW guidelines PDF. If PowerClerk asks for it, attach this year’s contract, not a 2022 template.
Fees: pay in the portal. Do not invent a UI residential fee here if the live PowerClerk invoice is the authority. Eversource publishes $200 / $163 more loudly on a public HTML table. UI may invoice differently. [NEED SOURCE: current UI residential interconnection and RRES application fee amounts on the live PowerClerk or uinet fee table.] Fast Track processing fees are listed on UI’s application-process materials; confirm before you bid a 100 kW roof. [CONFIRM AS OF 2026-09-19]
Fast Track, Study, and PE seals
Facilities that can use Fast Track are described on UI’s application-process page: induction, synchronous, or certified inverter-based generators producing between 25 kW and 2 MW that pass Connecticut State Guidelines Section 4.2.1 screens. Fail screens and you may still interconnect with modifications, or you go to study. PURA-approved Fast Track and Study guidelines (EDC document, UI copy hosted on uinet) say the EDC concludes initial application review within fifteen business days and returns results. That clock starts on a complete package, not on a one-line without a fee.
NRES Year 3 webinar tips (still the clearest UI-facing drawing advice in circulation) asked for a complete, consistent, correct application; an accurate site plan showing existing and proposed equipment, meters outside, grouped, disconnect; an accurate one-line showing existing and proposed additions, PE stamped if AC rating over 50 kW; site visit before apply; signed application; site control; UL 1741 SB inverters; insurance before contingent approval; electronic fee. Buy-All NRES jobs have extra field-engineering steps. If you are actually on NRES, do not use a 25 kW residential one-line.
When UI or the AHJ wants a seal, Athol coordinates a Connecticut-licensed PE stamp on the same sheets. Do not stamp a UI sample. Stamp the project.
Municipal drawings are parallel, not a substitute
New Haven building permits are electronic. Bridgeport wants the CT Standardized Solar PV Permit Application Supplement plus a zoning plan for solar, through the Park City Portal. Those PDFs do not populate PowerClerk. Keep kW, address, and inverter SKU identical. New Haven permit design and Connecticut design are the AHJ pages. This page is UI.
Cold sequence versus hot sequence shows up on larger services. NRES slides said instrument-rated (greater than 400 A), 480 V, or network services that are hot-sequenced (utility, then metering, then main disconnect) must be upgraded to cold-sequenced (utility, then main disconnect, then metering), and that this must appear on interconnection one-lines. If your C&I UI job has a 480 V service, ask that question before you trace a 200 A residential sample.
Comments we answer on United Illuminating solar interconnection files: microinverter job submitted on a central-inverter one-line, disconnect more than 10 feet from the meter with no dimension, missing title block, indoor meter with no relocation plan, unsigned application PDF, Fast Track job missing insurance, existing DG omitted, and a 30 kW roof on the 25 kW RRES form. Answer with a revised drawing, not a paragraph.
UI field engineering notes that belong on the first one-line
Photograph the meter, the main, the service lateral or riser, and the wall where you want the AC disconnect. UI comments about a disconnect more than 10 feet from the meter are geometry. If the only code-compliant wall is 15 feet away, dimension it and add the extra plaque they will want instead of hoping the sample drawing’s 3-foot offset applies.
Indoor meters: if the existing meter is in a closet, draw the proposed outdoor location, the grouping with any production meter, and the 24/7 access path. NRES guidance has been loud about outdoor grouped meters. Residential RRES jobs get similar comments more often than sales expects. Budget the relocation in the contract before UI writes it as a condition.
Microinverters versus string: pick the UI sample that matches. A microinverter job submitted on a central-inverter one-line with “x 12” written on the inverter block is a completeness fail. Show branch circuits, the load center or combiner, and the rapid-shutdown devices you will actually install.
Existing DG: a legacy 3 kW array on the garage is not “close enough to ignore.” Show it, nameplate it, and say whether it stays. Screens and protection reviews need the aggregate. Hiding it is how you fail a screen you could have passed with a sentence.
Fast Track insurance and site control: put them on the bid checklist for any job over 25 kW AC. A 40 kW roof on a small commercial is not RRES. It will not move without those PDFs. Do not tell the owner “UI is slow” when you never uploaded insurance.
Cold sequence on 480 V and instrument-rated services is a construction change, not a drafting flourish. If the existing gear is hot-sequenced, the one-line must show the new order and who owns the work. The electrician and UI field engineers should not meet the first time at a failed witness of a sequence nobody drew.
New Haven or Bridgeport comments that move a disconnect must flow to PowerClerk the same day. Two disconnect locations, one on the city set and one on the UI set, is a guaranteed fail for one desk.
Compare portal habits with Eversource on Athol’s Eversource vs UI post if your crew works both territories in one week. Then file UI as UI. Send the bill, photos of the meter and main, equipment list, and whether the job is 25 kW RRES or Fast Track. We will use UI’s sample list as the completeness punch card before a United Illuminating solar interconnection file hits PowerClerk.