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    Trip Units – part of the circuit breaker that opens the circuit in the event of a thermal overload.

    The main purpose of a circuit breaker trip unit is to selectively isolate faulted parts of the circuit breaker system. It must also allow short clearance times to limit the fault power and the effect of arcing faults. 


    As circuit breakers are an essential safety mechanism of one’s home, it is vital to be aware of how these unit breakers work and where they are readily available.


    Circuit Breaker Trip Unit

    A circuit breaker is an electrical switch, automatically operated with the purpose to protect an electrical circuit from damage that is caused by an overload of electricity or a short circuit. Circuit breakers are composed of several small circuits put together within larger circuits, which allow electrical charges to flow into a controlled system with even currents.


    The function of a breaker trip unit is to trip or open the operating mechanism in the event of a prolonged overload or short circuit fault condition. Aside from providing a means to open and close its contacts manually, a circuit breaker must automatically open its contacts when an overcurrent condition is sensed.


    The trip unit is the part of the circuit breaker that determines when the contacts will open automatically and opens the circuit in the event of thermal overload, short circuit currents, and specialist faults.


    Types of Trip Units

    Thermal Magnetic Trip Unit

    A thermal-magnetic trip unit has moving parts made up of a bimetallic thermal device that opens the circuit breaker with a delay depending on the magnitude of the overcurrent. This type of breaker trip unit has a system where magnetic forces equal to the current flowing through the circuit breaker are used to activate the breaker in the event of a short circuit. 

    Electronic Trip Unit

    An electronic trip unit is a machine-driven device that measures and times the current flowing through a circuit breaker and instigates a trip signal when appropriate.


    The electronic trip units use a microprocessor to process the current signal and operate the circuit breaker opening in case of fault. This type of trip unit provides more tripping criteria, which are not practical with electromechanical releases.

    How Does The Circuit Breaker Trip Unit Work?

    A trip unit works by opening the circuit of a circuit breaker in the event of a thermal overload, short circuit, or ground fault. The trip unit provides a level of safety as an open circuit will not conduct electricity because air or another insulator will stop or break the current flow in the loop.

    Our Product – Circuit Breaker Trip Unit Brands

    Electrical Supply Distribution offers breaker trip units in the Cutler Hammer brand, which is a brand known to provide a user-friendly experience; their breaker trip units promote higher levels of safety and inform homeowners when there are electrical problems that require urgent attention.


    Other brands of electrical supplies offered by ESD include:

    • Eaton General Electric
    • Siemens
    • Square-D

    Why Choose Us?

    When choosing Electric Supply Distribution for all circuit breaker trip unit needs, customers will receive competitive prices and products that offer high-quality electrical features.


    With over 10 years of experience in the electrical supply industry, they are known for offering their customers incredible pricing on a wide variety of inventory of the highest quality electrical products.

    Trip Unit Breaker From ESD

    For all things electrical, Electrical Supply Distribution has a team of professional and well-experienced individuals who are ready to assist. Call us today to get a free quote or contact us via our convenient online forum to have all your circuit breaker trip unit queries attended to.