Business Details
42 Years
experience
Your Trusted Electrical Contractors in Arvada, CO
Founded in 1984 by James and Joyce Cillessen, Interstate Electrical Contractors has established itself as a leader in substation construction and industrial power distribution. Our team operates with unwavering commitment to Safety, Quality, and Productivity, principles that have guided the successful completion of hundreds of projects nationwide. As a long-standing member of Associated Builders and Contractors, we maintain a 0.70 EMR safety rating and have earned multiple STEP Diamond Safety Awards. Our expertise spans turnkey substation solutions, underground transmission systems, and medium voltage projects for utilities, renewables, and industrial clients. With contract sizes exceeding $16 million and an average of $3.5 million, we deliver complex projects on time and within budget while maintaining exceptional craftsmanship.Client testimonials from industry leaders like Anadarko Petroleum and The Okonite Company affirm our reputation for excellence. Our regional focus on the Rocky Mountain and Southwestern United States allows us to provide specialized local knowledge while maintaining national capabilities.
Services
Substation Construction
Underground Distribution
Industrial Power Distribution
Medium Voltage Projects
Turnkey Substations
Transmission Line Installation
Switchyard Upgrades
Renewable Energy Integration
Utility Infrastructure
Government Contracting
Details
- Year established: 1984
Highlights and features
- We have completed hundreds of substation projects since 1984
- Our team maintains a 0.70 EMR safety rating with multiple STEP Diamond Awards
- We handle projects up to $16 million with proven on-time performance
- Our design/build capabilities deliver complete substation solutions
- Client testimonials confirm top 5% industry performance from experienced engineers
What people say
Completed ahead of schedule
High quality workmanship
Top 5% performance
Pleasure to work with
Expanded project scope
Services
Substation Construction
We design and construct complete power substations from initial concept to final commissioning. Our turnkey solutions include equipment procurement, civil works, and electrical installation for utility and industrial applications. With decades of experience, we ensure reliable infrastructure that meets evolving energy demands while maintaining strict safety protocols throughout the construction process.
Underground Distribution
Our underground power distribution systems provide safe, reliable energy delivery for urban and environmentally sensitive areas. We specialize in medium voltage cable installation, conduit systems, and termination work. Our expertise ensures minimal environmental impact while maintaining accessibility for future maintenance and system upgrades across diverse terrain conditions.
Industrial Power Distribution
We deliver customized power distribution solutions for industrial facilities including oil & gas operations and manufacturing plants. Our systems handle medium voltage requirements with precision engineering. From initial design to final implementation, we ensure uninterrupted power supply and compliance with industry-specific safety standards for continuous operational efficiency.
Renewable Energy Integration
We connect renewable energy sources to the grid through specialized substation infrastructure. Our work includes collector substations for wind and solar farms, ensuring efficient power conversion and transmission. We adapt traditional electrical systems to accommodate variable renewable energy inputs while maintaining grid stability and regulatory compliance for sustainable energy projects.
Switchyard Upgrades
We modernize aging switchyard infrastructure with advanced protection systems and digital controls. Our upgrades enhance grid reliability while extending equipment lifespan. We implement safety improvements and capacity expansions to meet current standards, minimizing downtime through phased implementation strategies during critical system upgrades.
People
Jim Cillessen
President
As President and co-founder, Jim Cillessen leads with 40+ years of electrical contracting experience. He oversees project execution and strategic growth while maintaining hands-on involvement in complex installations. His leadership maintains the company's founding principles of safety and quality.
Joyce Cillessen
Vice President
Co-founder Joyce Cillessen manages operations and client relations with decades of industry expertise. She ensures financial integrity and administrative excellence while supporting business development. Her oversight contributes to the company's consistent growth and client satisfaction since 1984.
Questions
What geographic areas do you serve?
We focus on the Rocky Mountain and Southwestern United States, with extensive experience in Colorado, Wyoming, New Mexico, and Texas.
What types of electrical projects do you specialize in?
We specialize in power substations, underground transmission lines, and industrial medium voltage systems for utilities, oil & gas, and renewable energy clients.
Are you equipped for large-scale projects?
Yes, we handle projects up to $16 million with an average contract size of $3.5 million, maintaining strict budget and timeline controls.
How do you ensure worker and site safety?
We maintain a 0.70 EMR rating with comprehensive safety programs that earned us four ABC STEP Diamond Safety Awards since 2018.
Can you handle complex design/build projects?
Yes, our design/build capabilities include preliminary engineering, cost estimation, and complete system implementation for turnkey substation solutions.
Reviews (3)
Helen Harloe
May 18, 2021
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Justin was amazing and super punctual. He removed a large foyer light and replaced it with a chandelier. He also looked at our oven lights and overhead lighting. Prices are super reasonable and he even educated me on buying fans for our attic to reduce our electric bill. 5 stars! Service: Outdoor lighting installation
Texas Measurement
Apr 01, 2021
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They actually care about the accuracy of their tools. Their team submitted tools for us to calibrate. Our local electrical company does not get them done. This shows they care a bout quality in their work
David Carrillo
Oct 30, 2017
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We would highly recommend this company. It was 45 minutes until they were to close and Justin did not hesitate one second to come to our daughter and son in laws home. The situation at the time was a potential fire ready to happen. Justin also made it happen to get everything fixed within two days. If there is a true definition to customer service this company is it. Thank you so much for keeping our family safe and giving us such a great deal cost wise. Sincerely Dave and Brenda Carrillo
