• AC-PRO, AC Trip Unit
  • AC-PRO, AC Trip Unit

    AC-PRO-II® Trip Unit

    The AC-PRO-II Trip unit is 55% smaller and has more features than the original AC-PRO.
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  • AC-PRO-MP installed an a Masterpact Breaker


    The AC-PRO-MP is a UL and CE listed, plug-in, direct replacement 60 Hz trip unit for the STR trip units on the Merlin Gerin & Schneider Electric Masterpact MP Circuit Breakers.
    Learn More

  • ZERO-Hertz DC Trip Unit


    The ZERO-Hertz trip unit is a solid state overcurrent device for use on one and two pole DC circuit breakers in voltage classes up to 1,000 volts.
    Learn More

  • QUICK-TRIP, Arc Flash Reduction System


    Dramatically reduce arc flash potential for those times when you must work on energized equipment down stream.
    Learn More

  • Retrofit Course, Earn NETA CTD credits

    Smart 1-Line is now available

    Smart 1-Line™ is URC's modern turn-key solution for monitoring your AC-PRO® and AC-PRO-II® networks at one convenient location.
    Learn More


Our offices will be closed on Friday July 3rd 2020 in observance of the American Independence Day Holiday. Emergency lines will still be available during this time.

March 24 2020

We're here for you

Keeping our employees, customers and communities safe and healthy is our highest priority at Utility Relay Company. We want you to know that as an essential business our commitment to providing outstanding service and solutions remains firm during these unprecedented times. We have been, and will continue to support those who need it most through our 24/7 phone, email, and online portal services. Please contact us at URCSales@utilityrelay.com or +1.888.289.2864. Thank you and stay safe.

Trip Units for Low Voltage AC and DC Circuit Breakers

Utility Relay Company is a leading manufacturer of microcontroller based, true-RMS solid-state trip units and trip unit retrofit conversion kits for AC and DC power circuit breakers. Utility Relay Company’s focus is providing high quality, reliable and versatile trip unit kits for low voltage circuit breakers.

The end result is an extensive line of retrofit kits that both provide reliable protection and are easy to install.

Utility Relay Company offers over 5000 complete conversion retrofit kit designs for existing power circuit breakers. Use our Kit Ordering Guide (KOG) to find the particular kits you need and to order directly online.

We design, produce, and offer kits for a variety of manufacturers’ breakers such as:

URC trip unit retrofit conversion kits replace legacy electromechanical series overload trip devices, thermal magnetic overcurrent releases, and older style electronic trip devices to provide greater accuracy, reliability, and functionality. Utility Relay Company provides life extension and modernization of older circuit breakers at a fraction of the cost of new breakers and eliminates the hassle of having to modify the switchgear.

Contact Utility Relay Company today to learn more about what we can do for you.

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