Eversource interconnection requirements

Sample preview — compiled from public sources 2026-08-19

Who this applies to

Eversource runs electric distribution in three New England states. This page covers the two with the most distributed solar activity, each under its own regime, kept separate throughout:

• Massachusetts (Eastern MA and Western MA service areas) — DG interconnects under the DPU-approved Standards for Interconnection of Distributed Generation, the statewide framework each Massachusetts utility files as its own tariff confirm current tariff revision. Eversource runs separate Eastern MA and Western MA DG groups.
• Connecticut — generator interconnection follows Eversource's published guidelines established under PURA Docket No. 03-01-15RE03, with tracks split by size and technology.

Covered project types in both states: solar, storage, and solar-plus-storage operating in parallel with the distribution system, residential through commercial scale. New Hampshire is Eversource territory too, but its separate state process is not covered on this page yet — see the FAQ. Wholesale and transmission-level interconnections are out of scope.

Application pathway overview

Both states apply through Eversource's PowerClerk online system — application, e-signature, payment, and status tracking in one place. An Eversource.com account is required; Connecticut DG contractor credentials also work for Massachusetts filings.

Massachusetts — three DPU paths

Connecticut — three PURA-guideline tracks

Required forms & documents

Massachusetts: the statewide Standards define the application package; Eversource takes it through PowerClerk. Structural contents:

• Simplified or Expedited/Standard interconnection application in PowerClerk, tied to the correct customer of record and service point confirm current revision
• Pre-application report — required for systems 250 kW AC and above
• Single-line diagram showing the point of common coupling, disconnects, and protection
• Equipment spec sheets — inverters meeting the IEEE 1547-series requirements Eversource publishes (new inverter requirements effective October 1, 2023 confirm current revision)
• Interconnection Service Agreement for Expedited and Standard projects
• Net-metering schedule information where the project takes net metering service
• Application fee payment per the fee schedule

Connecticut: per Eversource's Application to Connect page and the PURA-docket guidelines:

• Interconnection application in PowerClerk with e-signature confirm current revision
• One-line electrical schematic
• Site plan showing meter and AC disconnect location
• Proof of insurance — published coverage levels vary by capacity, from $300K to $5M verify current schedule
• Technical specification / data sheets with UL 1741 certification
• Proof of compliance with the applicable IEEE standards
• Guidelines acknowledgment for the correct track — inverter-based 25 kW or less, or Fast Track / Study Process
• Application fee payment (PowerClerk collects fees; Eversource has published options to pay at the final meter swap for some programs)

Print-ready packet checklist

Fees

Two separate schedules, both published by Eversource as accessed 2026-08-19.

Typical timeline stages

Massachusetts (statewide Standards, business days verify against Eversource's current tariff): every path starts with a 3-day acknowledgment and a 10-day completeness review.

1. Simplified — total maximum 25 days (30 with a screen #5 failure); the agreement is part of the application.
2. Expedited — screens within 25 days; Supplemental Review, if needed, 20 days; total maximum 45 days (65 with Supplemental Review).
3. Standard — initial review 20 days, Impact Study 55 days, Detailed Study 30 days; total maximum 135 days (160 if the application started in Expedited).
4. Witness test — within 10 business days of the Certificate of Completion, or by mutual agreement.

Connecticut (per Eversource's published table):

1. Application — submitted, e-signed, and paid in PowerClerk.
2. Review — 15 days for inverter-based systems 25 kW or less and Fast Track projects up to 2 MW; 105–120 days for Study Process projects above 2 MW.
3. Studies (Study Process only) — cost-based, scoped per the Fast Track and Study Process requirements.
4. Build, inspection, and meter work — install to the approved design and complete the utility's witness/meter steps before parallel operation.

Eversource has flagged that equipment lead times on ordered materials are unpredictable — from a couple of months up to a year or longer — which can affect any stage requiring utility-side equipment.

Common deficiency causes

Common ways applications fall short of the published requirements above — each item maps to a requirement in Eversource's or the state regulators' cited documents. Not drawn from SunDocket filing data.

• One-line schematic missing the point of common coupling, disconnect, or protection detail — both states require it explicitly
• Connecticut site plans that don't show the meter and AC disconnect locations
• Proof-of-insurance documents missing or below the published coverage level for the project's capacity (Connecticut)
• Inverter spec sheets without the required UL 1741 certification, or not meeting the IEEE 1547-series requirements Eversource publishes
• Customer or site data that doesn't match the Eversource account of record
• Massachusetts filings at 250 kW AC or above submitted without the required pre-application report
• Wrong track or wrong fee for the project's size and technology — both states' schedules vary by track
• Filing to the wrong Massachusetts DG group — Eastern MA and Western MA are handled separately

FAQ

Change log

• 2026-08-19 Page created from public sources.

Sources

• Eversource — DG, Interconnections & Net Metering (state directory) (accessed 2026-08-19)
• Eversource — Massachusetts Application to Interconnect (PowerClerk, paths, fee schedule) (accessed 2026-08-19)
• Eversource — Massachusetts Interconnection Resources (Eastern/Western MA DG contacts, tariffs) (accessed 2026-08-19)
• Eversource — Connecticut Application to Connect (PowerClerk, tracks, fee and timeline table, document list) (accessed 2026-08-19)
• Eversource — Connecticut interconnection resources (guidelines per PURA Docket No. 03-01-15RE03) (accessed 2026-08-19)
• Massachusetts Standards for Interconnection of Distributed Generation — statewide DPU framework, viewed via a utility tariff filing (time frames and fee tables) (accessed 2026-08-19)