A Connecticut interconnection application is filed with the electric distribution company that serves the meter: Eversource or United Illuminating (UI). Both follow PURA interconnection guidelines. Both use PowerClerk. They are not the same portal, the same queue, or the same email desk. File in the wrong PowerClerk and you will redo the interconnection application.
Permission to operate still comes from the utility after inspection and meter work. PTO, PPO, and permit to operate are installer shorthand for that closeout. Eversource’s public page talks about the application-to-connect lifecycle in PowerClerk. UI talks about interconnection and incentive-rate applications together for many Renewable Energy Solutions jobs. Read the status text. Do not energize on a yellow banner.
Eversource Connecticut
Start at Eversource’s Connecticut Application to Connect page. Guidelines and fees are filed with PURA. PowerClerk is how you initiate and track the job, including e-sign and payment.
Eversource publishes three application-fee rows on that page (confirm live):
- Residential inverter-based generators in the smaller guideline set: $200
- Fast Track (residential inverters greater than the small threshold; commercial and industrial ≤2 MW as they describe it): $500
- Study Process for complex projects greater than 2 MW: $1,000
A second table on the same page lists process, rating, time in business days, application fees, study fees, and liability insurance. Inverter-based 0 to 25 kW shows 15 business days and $200. Fast Track 0 to 2 MW shows 15 business days and $500 plus insurance. Study Process >2 MW shows 105 to 120 business days and $1,000 plus actual study cost. Those are Eversource’s published figures. They are not a guaranteed calendar for your feeder.
Drawing content they call out:
- One-line: utility voltage, main fusing, inverter make/model/rating, connectivity through the main and metering, isolation device, title block with customer name, address, revision
- Site plan: structures, metering, transformers, AC disconnect relative to the Eversource meter
- Isolation device visible and within 10 feet of the main utility panel, or clearly identified if farther, with written variance
- UL 1741 certification and IEEE surge references as they specify
- Insurance certificate when the table requires it (they list minimums by nameplate, starting at $300,000 above 0 to 100 kW on that table)
ISO-NE has a technical bulletin on utility-interactive inverters that Eversource flags for Connecticut applications. If you interconnect into Eversource CT, read that bulletin; do not assume a Massachusetts settings sheet is enough.
United Illuminating
UI’s application-process page and Renewable Energy Solutions interconnection page send residential and incentive jobs through UI’s PowerClerk. Fast Track in their write-up is for facilities in a mid size band that pass Connecticut guideline screens (they describe 25 kW to 2 MW class jobs that pass Section 4.2.1 screens). Study is for larger or failed-screen jobs.
UI also publishes interconnection fee rows (their page lists $200 for new 25 kW or less, $300 to upgrade from that track to Fast Track, $500 new Fast Track, $1,000 Fast Track 2+ MW, $150 additional site visit). Use UI’s live table, not Eversource’s, when the bill says United Illuminating.
UI often wants interconnection and RRES incentive materials in one package. That is convenient and easy to confuse. Incentive qualification is not PTO. See our Connecticut RRES installer guide for the incentive overlay, not as a substitute for this interconnection write-up.
Shared PURA rules, two desks
PURA Docket 03-01-15 and later orders sit under both EDCs. Technical screens are meant to be consistent. Day-to-day still differs: contacts, portal fields, whether RRES rides on the same ticket, how they label final approval.
Do not tell a Bridgeport customer “we filed Eversource.” Do not tell a Manchester customer to log into UI.
After you apply
Completeness, then screens or study, then an interconnection agreement, then build, then municipal electrical inspection, then meter work if the tariff needs a new meter, then written approval to operate. Moving forward in Connecticut is usually a PowerClerk task you own (upload the inspection, pay a fee, replace a one-line) rather than a phone campaign.
If the AC disconnect is 30 feet from the meter with no note, Eversource already told you that will bounce. Fix the permit design and the interconnection one-line together. PE stamps belong on the sheets that need a Connecticut PE in responsible charge.
Athol Energy files Connecticut interconnection drawings that match the AHJ set. State overview: Connecticut solar design services. City pages: Hartford, New Haven.
Sources: Eversource Connecticut Application to Connect, UI application process, UI Renewable Energy Solutions interconnections.