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Electrical Service Cost Estimator

Typical System Modifications and Estimated Costs for Commercial Customer Connections

Designed for developers, engineers, and commercial customers in the early stages of project planning.

Planning a new commercial project or upgrading your electrical service? Understanding the potential cost of electric infrastructure is a critical step in early project planning and budgeting. This page provides typical system modifications and estimated cost ranges for connecting commercial projects to the electric distribution system in Massachusetts. Use these estimates to:

  • Build preliminary budgets
  • Assess site feasibility
  • Anticipate infrastructure requirements
  • Prepare for discussions with National Grid during project design

Our goal is to provide transparency into potential infrastructure costs so you can plan with confidence and avoid surprises later in your project. Please keep in mind: actual project requirements and costs can vary based on site conditions, system capacity, and design needs. These estimates are intended for planning purposes only and are subject to change. For a detailed evaluation and precise cost assessment, we recommend working directly with our team. To start the process, please call Customer Service at 1-800-375-7405.

The sections below outline common types of distribution system modifications and their typical cost ranges. Many projects will require one or more types of system modifications/additions.

The intention of this list is to provide you with insight on the cost to build the required electric infrastructure. In some cases, a portion of these construction costs may be offset by the expected electric distribution revenue generated after your project is energized. If the projected revenue does not fully offset the construction cost, the remaining amount becomes a Construction Advance (also known as a Contribution in Aid of Construction, or CIAC).

To provide you with electric service, our team will determine the equipment and infrastructure needed to serve your project safely and reliably. This design reflects the least-cost approach needed to meet your service requirements. If features beyond what is required to provide standard service (for example, special routing or upgrades for convenience) are requested, those costs are not included in standard service and may result in additional charges. The tariff description for this policy can be found in Section IV under Policy 3, page 4 of 6 of the Terms and Conditions for Distribution Service document.

Distribution Line Scope System Modifications are those that require changes to feeders, conductors, switches, and other localized pieces of equipment. Estimates for work associated with our Substations, Transmission System, and Civil Construction are not listed due to the range possible within these areas. This listing and these estimates are based on our best knowledge of current requirements and actions; however, actual requirements and results may differ from the equipment listing/actions and cost estimates.

This listing will be updated annually on or around July 1. Last updated as of June 22, 2026.

Typical System Upgrade/System Modifications

Typical Scope

Typical Cost Estimates

Conductor upgrade/Reconductoring

Scopes for cost range:
1. Install/remove one mile of wire with crossarm construction* assuming 25% of poles will need replacements and transfer associated equipment.
2. Install/remove one mile of wire utilizing spacer construction* with all new poles transfer associated equipment.

$1,331,000 - $1,959,000 per mile

Voltage Conversion

Scopes for cost range:
1. Install/remove one mile of bare wire*, assuming 25% of poles will need replacements, refurbish existing infrastructure, install/remove overhead transformers, and transfer associated equipment.
2. Install/remove one mile of wire utilizing spacer construction with all new poles transfer associated equipment, install/remove overhead transformers, and remove one mile of crossarm construction 

$2,007,000 - $2,379,000 per mile

Express Feeder extension - Double Circuit

Scopes for cost range:
1. Install one mile of spacer construction assuming 25% of poles will need replacements and transfer associated equipment
2. Install one mile of spacer construction assuming 100% of poles will need replacements and transfer associated equipment

$1,246,000 - $2,340,000 per mile

New Overhead Line extension

Scopes for cost range:
1. Install one mile of bare wire, crossarm construction with associated equipment
2. Install one mile of spacer construction with associated equipment

$1,084,000 - $1,373,000 per mile

Overhead Line extension – Single-phase to three-phase

Scopes for cost range:
1. Remove single-phase wire and install one mile of three-phase spacer construction assuming 25% of poles will need replacements and transfer/remove associated equipment as applicable
2. Remove single-phase wire and install one mile of three-phase spacer construction assuming 100% of poles will need replacements and transfer/remove associated equipment as applicable

$1,126,000 - $1,525,000 per mile

Install Overhead Primary Metering

Install new pole and overhead primary metering and associated equipment. Cost varies by size.

$50,000 - $54,000 

Single-Phase Overhead Transformer upgrade/installation (25-50kVA)

Scopes for cost range:
1. Install/remove a single-phase 25kVA overhead transformer
2. Install new pole, install/remove overhead transformer and transfer associated equipment

1. $5,000 - $15,000
2. $10,000 - $25,000

Three Overhead Transformer upgrade/installation (25 - 300kVA)

Install/remove a three-phase overhead transformer. Cost varies by size.

$20,000 - $68,000

Single-phase riser pole installation 

Install a pole with equipment to transition wire from underground to overhead and associated equipment. Range varies by size of pole.

$10,000 - $20,000

3-phase riser pole installation 

Install a pole with equipment to transition wire from underground to overhead and associated equipment. Range varies by size of pole.

$39,000 - $41,000

Recloser upgrade/installation 

Install a recloser and bypass disconnects. Price varies by size.

$137,000 - $149,000

Typical System Upgrade/System Modifications

Typical Scope

Typical Cost Estimates

Single-phase Pad-mounted Transformer upgrade/installation (25- 100kVA)

Install minipad foundation, transformer, and associated equipment. Cost and size varies by size. (25- 100kVA)

$10,000 - $30,000

Three-phase pad-mounted Transformer upgrade/installation (75 - 2500kVA)

Install transformer and associated equipment. Cost varies by size.

$32,000 - $102,000

Pad-mounted switchgear installation 

Install switchgear and associated equipment. Cost varies by size.

$129,000 - $208,000

Underground cable installation

Install one mile of cable in existing manhole and duct system with associated manhole racks and other equipment. Cost varies by complexity.

$691,147 - $898,491

Conductor upgrade/Reconductoring

Remove and replace one mile of cable in existing manhole and duct system with associated manhole racks and other equipment. Cost varies by complexity.

$729,107 - $947,839

UG Line extension – Single-phase to three-phase

Remove single-phase and replace with three-phase cable one mile of in existing manhole and duct system with associated manhole racks and other equipment. Cost varies by complexity.

$691,147 - $898,491

UG Primary Metering

Install riser pole and approximately 350’ of cable from riser to primary meter set up, pad-mounted recloser, pad-mounted primary metering cabinet, and pad-mounted switchgear. Cost varies by equipment size and set up.

$373,016 - $484,920

*Key Terms    

Crossarm construction: The hardware, materials, and methods used to attach and support horizontal arms on utility poles. These crossarms are used to separate, insulate, and secure power lines.

Spacer construction: An overhead power line arrangement where three heavily covered phase conductors are bundled and suspended beneath a high-strength messenger cable using durable plastic spacers. It is widely used by utility companies to minimize the risk of tree-contact fires, reduce outages in wooded areas, and shrink the required right-of-way footprint.

Bare wire: Bare wire is wire with no insulation. While lighter and less expensive, it is also more vulnerable to issues if it is touched or struck.