Business Details
42 Years
experience
Your Trusted Electrical Contractor in Arvada, CO
Founded in 1984 by James A. Cillessen and Joyce K. Cillessen, Interstate Electrical Contractors has grown into a leading electrical contracting firm serving the Midwest and Western United States. With over 40 years of experience, we specialize in power substation construction, underground distribution/transmission, and industrial medium-voltage power distribution projects. Our team executes complex electrical infrastructure projects using three core principles: Safety, Quality, and Productivity. As a long-standing member of Associated Builders and Contractors (ABC), we maintain a 0.70 EMR safety rating and have earned multiple ABC STEP Diamond Safety Awards. Our expertise spans design/build capabilities, from preliminary outline drawings to hard dollar pricing, delivering turnkey substation solutions. We have successfully completed hundreds of projects across the U.S., including large-scale contracts exceeding $16 million.Client testimonials highlight our ability to deliver high-quality work ahead of schedule while maintaining strict budget adherence. Our leadership team, including President Jim Cillessen and Vice President Joyce Cillessen, brings decades of industry experience to every project. We maintain bonding capacity through Westfield Insurance Company and serve key markets including utilities, renewables, industrial/oil & gas, and government sectors. Our project portfolio demonstrates consistent execution excellence, with clients like Anadarko Petroleum Corporation expanding our scope based on proven performance.
Services
Substation Construction
Underground Distribution
Transmission Projects
Industrial Electrical
Design/Build Services
Details
- Year established: 1984
Highlights and features
- We have over 40 years of experience in electrical contracting
- We maintain a 0.70 EMR safety rating with multiple ABC STEP Diamond Awards
- Our team executes complex projects exceeding $16 million in value
- We offer proven design/build capabilities from concept to completion
- Our clients consistently expand project scopes based on performance
Associations and certifications
- Associated Builders and Contractors (ABC)
What people say
Completed ahead of schedule
High quality workmanship
Top 5% performing crew
Expanded project scope
Pleasure to work with
Services
Substation Construction
We design and build complete power substations from concept to commissioning. Our turnkey solutions include all electrical components, structural elements, and system integration. With decades of experience executing complex projects across the Western and Midwestern U.S., we deliver reliable infrastructure for utilities and industrial clients.
Underground Distribution
Our medium-voltage underground distribution expertise includes installation, replacement, and maintenance of critical electrical infrastructure. We specialize in challenging environments like Fort Randall Dam and Oahe Switchyard projects, ensuring safe and efficient power delivery for government and utility clients.
Industrial Electrical
We provide specialized electrical solutions for industrial facilities including oil & gas plants and manufacturing centers. Our capabilities range from initial design to final commissioning, with project experience spanning from $3.5 million average contracts to complex $16 million+ installations.
Design/Build Services
We offer full-service design/build capabilities, transforming client requirements into complete electrical systems. Our process includes preliminary engineering, cost estimation, and execution of detailed construction plans while maintaining strict safety and quality standards throughout project lifecycles.
Transmission Projects
Our transmission expertise covers 115kV underground systems and high-voltage infrastructure. We deliver reliable solutions for utility clients like Teton Village and Foothills Substation projects, combining technical precision with proven safety performance across diverse geographic regions.
People
Jim Cillessen
President
As President and co-founder, Jim Cillessen leads with over 40 years of electrical contracting experience. He drives strategic growth while maintaining operational excellence across complex infrastructure projects nationwide.
Joyce Cillessen
Vice President
Vice President Joyce Cillessen co-founded the company and oversees key operations. Her leadership ensures consistent delivery of high-quality electrical solutions while maintaining the organization's founding principles.
Questions
What electrical contracting services do you offer?
We specialize in power substation construction, underground distribution systems, industrial electrical projects, and turnkey transmission solutions.
What geographic areas do you serve?
We primarily operate in the Rocky Mountain and Southwestern regions of the United States.
What safety certifications do you hold?
We maintain a 0.70 EMR safety rating and have earned multiple ABC STEP Diamond Safety Awards.
What project sizes can you handle?
We execute projects ranging from $3.5 million average contracts up to complex $16 million+ infrastructure developments.
How do you ensure project quality?
Our quality assurance follows three core principles: Safety, Quality, and Productivity across all project phases.
What industries do you work with?
We serve utilities, renewables, industrial/oil & gas, and government sectors with specialized electrical solutions.
