Contact Information

Interstate Electrical Contractors, Inc. specializes in power substations, industrial and medium voltage power distribution projects.

12725 West 54th Drive Arvada, Colorado 80002 (303) 420-6400
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Interstate Electrical

Founded in 1984 by James A. Cillessen and Joyce K. Cillessen, Interstate Electrical Contractors, Inc. has grown to be an experienced electrical contractor in the Midwest and Western United States. Interstate Electrical Contractors has successfully completed hundreds of substations and underground medium voltage distribution projects throughout the United States. Using the three core principles of Safety, Quality, and Productivity, IEC has successfully executed these jobs. We are a long-standing member of Associated Builders and Contractors (ABC).



Jim Cillessen

Vice President

Joyce Cillessen


ABC STEP Diamond Safety Award


ABC STEP Diamond Safety Award


ABC STEP Diamond Safety Award


ABC STEP Diamond Safety Award

Founded on the Core Principles of

Safety, Quality & Performance


EMR Safety Rating

Project Bonding Through Westfield Insurance Company

Have Performed Contract Sizes over $16,000,000

Average Contract Size $3,500,000

Interstate Electrical Contractors did a very good job at completing this project in the time specified with attention to detail and workmanship. Anadarko will be using them again on our next substation named Amberjack. Based on their work at Pecos Express we have expanded their scope to include the entire construction of the Amberjack facility.

U.S. Onshore Power Engineering Supervisor

Anadarko Petroleum Corporation

I am happy to say that the work was completed ahead of schedule within budget and was of high quality workmanship…The whole Interstate Electrical Contractors team were a pleasure to work with.

Electrical Superintendent

Colorado Highlands Wind Project

Over my 40 plus years with Okonite I’ve witnessed crews working on numerous construction and utility sites and your crew at Fort Randall rank in my opinion, in the top 5% and I wouldn’t have to be pressed to say, “they are the best” I’ve seen.

Regional Engineer

The Okonite Company