Commonwealth Edison.

Quality, Safety, and Timeliness

Project Description

These project pages demonstrate a few projects that ran concurrently, for the same client, with the same deadlines. Most of our projects must be executed with very strict adherence to a timeline. Part of the economics of a project involves timeliness; projects that do not finish on time never finish under budget. Projects that finish on time usually finish on budget.

Northwest Contractors has done hundreds of projects for Commonwealth Edison, usually in energized substations. Only through a high level of quality, safety, and timeliness can such a relationship exist.

In 1998 the city of Chicago experienced difficulties with the back-up and redundancy systems in its electrical supply. Commonwealth Edison vowed to solve the significant problem in record time. ComEd hired ABB Power T&D Company to design the system upgrades and manage the construction. ABB partnered with MJ Electric and Northwest Contractors.

Our responsibility was to perform all structure, excavation, concrete & ductwork for the new substations and to design and build three substation buildings. Each building required a 10,000 square foot footprint with 1 story below grade and 5 stories above grade. Design started in late December, all three buildings were under roof by April and all sites were energized on June 1st.

In addition to the fact that construction took place through the winter, each building had its own challenges. All three of these jobs ran concurrently, were under roof in four months, and the substations were energized by June.

California & Addison

Located between two transformers, our addition to this existing substation required that every yard of concrete and every pound of steel be placed while the transformers were live. In projects such as this, there is no room for error. There is no compromise in quality. Safety is paramount!


This site project involved a lot size of one acre, and new building of a control building and a 26 foot high, masonry screen wall. As with the other sites, the shear volume of work to be performed in such a short time frame created the biggest challenge. However, this site had the additional challenge of requiring the retention of 50,000 gallons of rainfall before a slow discharge through an oil-water separator and then into the city sewer system. Because of the extensive underground work within the footprint of the station, locating suitable storage for such a large amount of water presented a unique problem. With nowhere to store the water within the station, we designed the foundation of the perimeter screen wall as a box culvert to store the storm water.

Ohio & Kingsbury

This building was added to an existing substation. Live underground utilities, live transformers, and existing buildings created additional challenges. This substation is 10,000 square feet with floors that are 3 feet thick. With walls that are almost 5 story, pre-cast panels, the particular challenge of this project was access. We could only have access to it from Kingsbury because the other buildings you see in these photos were in the way. Usually, the frame goes up first and the panels attach to the frame. However, if we built the frame first, we would have had a 45 foot high by 2 foot wide space to maneuver up, over, and into. What did we do? We temporarily secured the panels and then built the final, structural frame with the panels already placed.

Project Details

  • Client Commonwealth Edison
  • Date August 24, 2015
  • Tags Architecture
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