TOMAC
SubstationConnecticut
At a glance
TOMAC is an electric transmission substation in Connecticut. It is classified as sub-transmission (115 kv) and connects 1 transmission line. Substation proximity is one of the strongest speed-to-power signals for siting a datacenter — interconnection distance to an energized, high-voltage bus is often the binding constraint on time-to-energization.
Voltage & classification
Ownership
No owner is recorded for the lines that connect here.
Connected transmission lines
Lines terminating at or passing through this substation, by HIFLD line ID, highest voltage first.
| Line ID | Voltage | Owner | Status | Length |
|---|---|---|---|---|
| #106683 | 115 kV | — | IN SERVICE | 1.9 mi |
| #131072 | 115 kV | — | IN SERVICE | 0.0 mi |
| #149324 | 115 kV | — | IN SERVICE | 1.7 mi |
Nearby datacenter candidate sites
Scored candidate sites within roughly 25 miles of TOMAC, ranked by DC Readiness. Sites this close to an energized substation carry a strong speed-to-power advantage.
| Site | Type | State | County | Voltage | Capacity | Queue wait | Score |
|---|---|---|---|---|---|---|---|
| RAINEY | Substation-Adjacent | NY | New York County | 345 kV | 600 MW | 4.3 yrs | 72.2 |
| BRIDGEPORT RESCO | Substation-Adjacent | CT | Greater Bridgeport Planning Region | 345 kV | 600 MW | 4.3 yrs | 71.7 |
| Charles Poletti | Brownfield | NY | New York | 138 kV | 883 MW | 4.3 yrs | 71.2 |
| DUFFY AVENUE CONVERTER STATION | Substation-Adjacent | NY | Nassau County | 500 kV | 1,000 MW | 4.3 yrs | 70.2 |
| SHORE RD | Substation-Adjacent | NY | Nassau County | 345 kV | 600 MW | 4.3 yrs | 68.8 |
| PLUMTREE | Substation-Adjacent | CT | Western Connecticut Planning Region | 345 kV | 600 MW | 4.3 yrs | 68.2 |
| EAST GARDEN CITY | Substation-Adjacent | NY | Nassau County | 345 kV | 600 MW | 4.3 yrs | 67.6 |
| UNKNOWN129188 | Substation-Adjacent | NY | Westchester County | 345 kV | 600 MW | 4.3 yrs | 67.4 |
How does TOMAC compare with other substations in Connecticut?
Connecticut has 300 substation records in HIFLD, of which 154 carry a station name; the rest are unnamed tap points, risers and line ends. 121 named substations in the state are in TOMAC's 115–229 kV band (79% of named stations). 20 sit in a higher band. 20 named substations in Connecticut operate at 345 kV or above. The highest voltage recorded in the state is 345 kV, and the state median is 115 kV.
How do candidate sites near TOMAC score?
The 8 highest-scoring candidate sites within about 25 miles range from 67 to 72 on the 0–100 DC Readiness scale. They fall in New York County, Greater Bridgeport Planning Region, New York, Nassau County. The Connecticut average across 919 scored sites is 56.7. 171 of those Connecticut sites are classed as substation sites (candidate locations generated at an existing substation).
Frequently asked questions
What voltage is TOMAC substation?
TOMAC has a maximum voltage of 115 kV. That places it in the 115–229 kV band. The median named US substation in this dataset is 115 kV, so TOMAC is at the national midpoint.
How many transmission lines connect to TOMAC substation?
1 transmission line terminate at or pass through TOMAC in the HIFLD line data. The connected lines listed here run at 115 kV. Together the listed lines cover about 3.7 miles.
Where is TOMAC substation located?
TOMAC is in Connecticut at 41.0340, -73.5634. The datacenter candidate sites closest to it are in New York County, Greater Bridgeport Planning Region, New York.
Are there datacenter candidate sites near TOMAC substation?
GridCensus lists at least 8 scored candidate sites within roughly 25 miles of TOMAC. The highest-scoring is RAINEY at 72/100. Across Connecticut, the average DC Readiness score is 56.7.
Other 115 kV substations in Connecticut
- DEVON· 13 lines
- TUNNEL· 7 lines
- BERLIN· 6 lines
- MIDDLETOWN· 6 lines
- MILFORD POWER· 6 lines
- SOUTH MEADOW· 6 lines
- STEVENSON· 6 lines
- BOKUM· 5 lines
- All named substations in Connecticut· 154 stations
- Datacenter candidate sites in Connecticut· 919 sites
- Brownfield and retired plant sites in Connecticut
- Substations by state
About this data
Source: HIFLD Electric Substations and Transmission Lines (U.S. Department of Homeland Security), as published June 29, 2026. See the methodology for how records are matched, cleaned and scored.
Cite as: GridCensus, “TOMAC substation, Connecticut”, https://gridcensus.com/substations/connecticut/tomac-d6acb6f0 (data as of June 29, 2026).
Dataset updated . Screening estimates derived from public data sources.
Substation attributes are derived from public HIFLD / EIA infrastructure data and may lag real-world upgrades or retirements. Voltage and connected-line counts are screening figures — confirm available capacity and interconnection terms directly with the operating utility and ISO.
Go deeper than the public screen
Every site and score for TOMAC substation, Connecticut is free to browse. Pro adds Watchtower on 25 sites, alerts when new candidate sites, datacenters or interconnection-queue requests appear in your markets, score and capacity history, and CSV export. Enterprise adds team seats, weekly data files for all 147,272 sites, the REST API and an MCP server for AI tools.