Working With Tricky Estimates: A day in the life on a complex project

Shutterstock / Thunderstock
Shutterstock / Thunderstock
Published On
Jul 15, 2022

As I write this, I am working on one of the more complex estimates I have taken on recently. Even though I have estimated more than 100 sewage pump stations, this one is very different. There are many things I have never seen before, making it a more difficult takeoff to perform. I thought you might be interested in the process I used for understanding and completing the estimate for an exceptionally challenging project.

Project description

This project is a new sewage pump station and it is larger than most I have worked on. The service is 600A, 480V three-phase, 3-wire. There is also a 600A motor control center that mostly serves an odor-control system. The eight 100-horsepower pumps are controlled by four duplex variable-frequency drives (VFDs). The structures consist of a block building for the electrical and mechanical rooms, a large, underground dry well where the pumps will be installed and two underground wet wells. The wells are defined as hazardous locations, National Electrical Code Class 1, Division 2.

The items I have not seen in a small pump station before are eight pumps, an odor-control system, duplex VFDs, the large number of redundancies and equipment installed in a large, hazardous, underground area.

The complexities of pump placement

The biggest challenge is the pump placement. In most of the projects I have estimated, the pumps are placed above ground, but this one has them in a large, underground dry well. The interior dimensions are 60-feet-long-by-24-feet-wide-by-20-feet-tall. The concrete walls are 3 feet thick. The entire area is a hazardous environment, so everything in it must comply with Code requirements for this classification. For most of my estimates, this area only includes a few float switches. For this project, it includes the 100-horsepower pumps, lighting, receptacles, switching, motor controls, sump pumps and instrumentation.

The pumps and instruments have a factory-terminated cable that is run through a cable tray system to the southeast corner of the dry well, where it enters a conduit system routed to terminal boxes on the outside of the electrical room. One complexity was separating the factory-supplied cable from the cables the contractor needed to supply, because the feeder schedule did not indicate the cables were furnished by others.

Due to the redundancies, the control requirements are much more complex than the pump stations I am familiar with. The controls alone require 70 feeders. The control single line—unzoomed on a 32-inch monitor—is almost a blob of black. Only by zooming in very close could I see the lines and text clearly. I feel sorry for estimators trying to perform this estimate on paper plans.

The final complexity is the immense number of notes and details on these plans. There are 20 or more notes on each plan sheet, in addition to 73 keynotes on a separate sheet. There are also 55 highly detailed diagrams spread throughout the plan set.

A strategy to work this project

My No. 1 strategy for dealing with projects such as this is to perform a review of all the electrical drawings before starting the takeoff. I also study some relevant drawings from other trades, including mechanical and architectural ones. By studying the plans before starting takeoff, I have built a general map in my mind of the project, in which I just need to fill in specific details.

I made a mistake on this project by not reading the 73 keynotes before starting the takeoff. A few feeders I had already taken off needed to be corrected because the keynotes required the pump manufacturer to provide the pump feeder cables. Fortunately, I learned about this requirement before taking off the instrumentation feeders, because they had the same requirement.

My order of takeoff for work this complex is different from other projects. After counting the light fixtures and sending the counts for quotation, I takeoff the feeders, as they can consume 80%–90% of the takeoff time. It is very important to study any detail referred to during the takeoff. Correcting takeoff costs a lot of time if you need to go back and fix it later.

On my final pass through the drawings, I found some small print that required stainless-steel conduit for penetrations into the wet well. That would have cost my customer over $20,000 if I had missed it. Projects such as this one require more time than usual to perform the takeoff. Study the notes and details carefully, as a small omission could cost thousands of dollars.

About the Author

Stephen Carr

Estimating Columnist

Stephen Carr has been in the electrical construction business since 1971. He started Carr Consulting Services—which provides electrical estimating and educational services—in 1994. Contact him at 805.523.1575 or steve@electrical-estimating.com, and...

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