How do I apply for solar interconnection in Massachusetts, Rhode Island, or Connecticut? You apply to the utility that holds the customer’s electric account, through that utility’s portal, using the process track that matches nameplate and service type. You do not apply to the town building department for grid permission. The town permit and the interconnection application run in parallel. Permission to operate (PTO, sometimes called PPO or permit to operate) comes last.
This is the practical sequence we use on East Coast residential and light commercial jobs. Confirm every fee and day count on the live tariff. Those numbers change.
1. Confirm territory and account
Massachusetts jobs land on National Grid, Eversource, Unitil, or a municipal light plant. Rhode Island Energy covers most of Rhode Island. Connecticut is Eversource or United Illuminating (UI). The portal will reject an interconnection application if the address and account number do not match billing.
Rhode Island Energy tells applicants that a new or upgraded service should be requested before the DG interconnection application if there is no existing account or if you are putting three-phase generation on a single-phase service. Skipping that step is a common reason a “complete” packet is not actually complete.
2. Pick the right process before you open the form
National Grid Massachusetts describes Simplified for small listed inverter-based systems (its DG process page currently cites 15 kW single-phase / 25 kW three-phase on radial circuits). Expedited or Standard is for everything that does not fit. Pre-application reports are mandatory at 250 kW aggregate nameplate and optional below that.
Rhode Island Energy Simplified is listed inverter-based, 25 kW or less, radial, passing the tariff screens. Spot or area network jobs that look Simplified on paper often leave that track.
Connecticut Eversource’s Application to Connect page lists three published buckets: residential inverter-based generators in the smaller guideline set, Fast Track, and Study Process, with application fees shown as $200 / $500 / $1,000. UI uses its own PowerClerk instance under the same PURA guidelines. Do not create an Eversource PowerClerk job for a UI service address.
If you are unsure, read the utility’s current process page rather than last year’s spreadsheet.
3. Build the solar interconnection application package
A typical Massachusetts, Rhode Island, or Connecticut interconnection application includes:
- Customer legal name and service address exactly as billed
- Installer / interconnecting customer contacts
- kW AC nameplate, DC STC, inverter make and model
- UL 1741 listing for inverters
- One-line showing utility voltage, main, inverter, isolation device, and meter
- Site plan with the AC disconnect relative to the meter
- Cut sheets
- Signed terms or Exhibit A
- Application fee
- Insurance certificate when the Fast Track or Study track requires it (Eversource publishes minimum liability by nameplate on the Connecticut page)
Eversource Connecticut wants the isolation device visible and within 10 feet of the main utility panel, or clearly identified if it is farther, with written variance. That note belongs on the drawing, not in a sidebar comment the reviewer will miss.
Match this one-line to the permit design set. If sales sold a different inverter after the town packet went in, update both files before you hit submit.
4. Submit in the portal, then wait for completeness, not “submitted”
National Grid Massachusetts: after a Simplified case is submitted, the company has a completeness window (its Simplified application article currently cites 10 business days to review documents). Issues put the case on hold. A clean package moves to screening. Screening has its own tariff clock.
Rhode Island Energy CEI acknowledges materials, assigns an application number, and only then treats the interconnection application as complete. Incomplete means missing exhibits, not “we uploaded something.”
Connecticut PowerClerk (Eversource or UI) shows the next responsible party after e-sign and payment. Watch that queue. If the portal is waiting on you, the utility clock is not running.
5. Conditional approval is not PTO
Once screens pass, you get conditional approval to construct, an Interconnection Service Agreement (ISA) on expedited/standard tracks, or the portal equivalent. Build to that design. Field changes need a revision. Energizing for production before written authorization is how you pick up liability and billing problems.
Rhode Island Energy’s completion process is explicit: submit completion documents after install, wait for the bi-directional meter if you applied for net metering, then wait for Authorization to Interconnect. Operating behind a detented revenue meter can scramble billing.
Massachusetts closeout is a completion package plus, on Simplified, National Grid’s interconnect email after a clean review. Connecticut closeout is utility approval after municipal inspection and any meter work. Call it PTO, PPO, or permit to operate. The rule is the same: written utility OK.
6. Inspection, then moving forward
The electrical inspector signs the AHJ side. That sticker does not interconnect you. Upload the certificate of completion, as-builts if the array moved, inverter serials if asked, and the signed customer forms. If CEI or National Grid returns one item, fix that item.
PE-stamped one-lines reduce back-and-forth when the reviewer questions conductor size or disconnect rating. They do not skip completeness.
What this looks like on a real MA/RI/CT week
Monday: confirm account, process track, and whether a pre-application is required. Tuesday: freeze equipment. Wednesday: submit the interconnection application with the same one-line as the town set. The rest of the week is not “following up daily.” It is watching completeness notices. After install, the bottleneck is usually the meter appointment or a missing Exhibit A2, not the roof.
Athol Energy builds interconnection applications next to the permit set so installers in Massachusetts, Rhode Island, and Connecticut are not maintaining two conflicting drawings. Send territory, nameplate, and the bill PDF if you want a completeness pass before the portal.
Sources: National Grid MA process, Submitting MA Simplified Application, RI Energy project completion, Eversource CT Application to Connect, UI application process.