What to Expect
We appreciate and thank you for your patience as we work hard to safely improve electric reliability in your neighborhood.

Over the next few months, you may see several different construction operations performed within city streets including excavation, the installation and welding of pipe, and roadway restoration.

One of the first activities that you may see is survey work to determine the limits of the excavation area as well as representative from Digsafe marking the location of other utilities in the roadway.

The first significant construction activities you may see are crews performing saw cutting and excavation operations within city streets.
  • Ethernet Cable
  • Spectacles
  • Ethernet Cable
  • Spectacles
  • Ethernet Cable
  • Leaning Tower of Pisa

The width of the trench is marked on the street and the pavement is saw cut. The saw cutting provides a clean break in the pavement and defines the trench for the digging activity. Saw cutting will occur several hundred feet ahead of the excavation crew.

As excavation begins, a backhoe is used to remove asphalt and sub-surface materials. The resulting trench is typically about 4-5 feet in both width and depth.

Dump trucks are used to remove the excavated materials off site daily for recycling or disposal. As crews complete excavation of an area, shoring may be installed to facilitate the installation of pipe.

Throughout the construction process, steel road plates are used to cover the trench when work is not occurring, and the site is swept clean each work day.

Typically, construction crews will occupy a designated work zone area, leaving the remaining roadway open for traffic to pass. In some areas where streets are narrow, it will be necessary to detour traffic, and signage will be clearly posted to direct motorists.

Following the trench digging crews will begin to install pipe. Workers will bend and fit 8-inch diameter steel pipe into the trench. The pipe is delivered on site typically utilizing a flatbed truck, and lowered into the trench using a crane. The pipe sections are then welded together and an X-ray of each weld is taken to ensure integrity.

After the quality control inspections are completed, the trench will be backfilled with a thermal sand to surround and bury the pipe. This concrete material, delivered by cement mixing trucks, helps to prevent settling of the trench which ultimately results in a better quality road surface. This concrete is filled up to within a few inches of the road surface, and the trench is then paved even with the street level.

At the end of the project, the line will be filled with dielectric cooling fluid. The bulk of this work will be performed from within the substations using larger fluid delivery trucks.

It is anticipated that construction will typically progress past a given location within approximately two to four weeks. The general work hours are between 7 am and 4 pm from Monday through Friday. Night work will occur in select non-residential areas generally between 8pm and 5am. This is a window of time during which construction will take place, although crews may not be in the work zone during the entire span.

Construction of the line does not require any scheduled interruptions in electrical service.

Copyright 2011, NSTAR, all rights reserved.
Legal Statements
Hotline number is 617-571-4582
Cambridge Reliability Project | What to Expect | Community Outreach | FAQ | Progress Photos