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JCOF Auxiliary Contact

MCB Accessories

JCOF Auxiliary Contact

JCOF auxiliary contacts are mechanically operated contacts in an auxiliary circuit. It is physically connected to and activated simultaneously with the main contacts, providing an additional level of control and security to the circuit. Although it does not carry as much current as the main contact, its role as an auxiliary or control contact is vital to ensuring the proper functioning of the circuit. In addition, auxiliary contacts are often used to provide feedback or signals on the status of the main contacts, thereby enhancing monitoring and control of electrical systems.


    A JCOF auxiliary contact (or switch) is an auxiliary contact added to a circuit to protect the main contact. This accessory allows you to check the status of your miniature circuit breaker or supplementary protector from a remote location, providing convenience and enhanced monitoring capabilities. Auxiliary contacts facilitate efficient management of electrical systems by remotely determining whether a circuit breaker is open or closed. Furthermore, the functionality of the auxiliary contact goes beyond remote status indication as it plays a vital role in preventing unnecessary power being supplied to the contactor coil in the event of a power circuit failure.
    The function of a miniature circuit breaker is to protect the motor by cutting off the power supply in the event of a fault such as a short circuit or overload. However, closer inspection of the control circuit revealed that the connection may have remained closed, causing unnecessary powering of the contactor coil. This is where auxiliary contacts come into play, providing an extra level of control to prevent situations like this from happening.
    The function of an auxiliary contact is to allow one switch to control another switch (usually a larger switch). It consists of a coil with two sets of low-current contacts at each end and high-power contacts inside. Contact groups designated as "low voltage" are often identified, clearly indicating their purpose in the circuit. This demonstrates the versatility and importance of auxiliary contacts in ensuring efficient and safe operation of electrical systems.
    The auxiliary contacts are similar to the main power contactor coils and are designed to operate continuously throughout the plant and are equipped with a time delay element to prevent arcing and potential damage if the auxiliary contacts open while the main contactor is still energized. This feature ensures the safe and reliable operation of the electrical system.
    Auxiliary contacts serve a variety of purposes and are critical to the efficient operation and protection of electrical equipment. They are used to obtain feedback from the main contactor in the event of a trip, providing valuable information for troubleshooting and maintenance. Additionally, auxiliary contacts play a vital role in protecting circuit breakers and other equipment, helping to better protect against electrical damage and reduce the likelihood of electrical failure. By enhancing the durability of circuit breakers, auxiliary contacts help increase the overall reliability and service life of electrical systems, making them an indispensable component in industrial and commercial applications.

    Product Description

    Main Features

     ● OF: Auxiliary, it can provide MCB "trip" and "close" status information, providing valuable feedback for the status of circuit protection devices.
     ● Indicates the location of device contacts for easy monitoring and visual confirmation of MCB operation.
     ● Special pin design is adopted and installed on the left side of MCB/RCBO to ensure convenient and safe installation while maintaining correct alignment with the circuit protection device.

    Difference between the main contact and the auxiliary contact:

    In an MCB, it is the principal contact mechanism that connects the load to the supply. Control, indicator, alarm, and feedback circuits use auxiliary contacts, also known as helpful contacts
    The main contacts are NO (normally open) contacts, which signifies they will only establish contact when the MCB’s magnetic coil is powered. Both NO (Normally Open) and NC (Normally Closed) contacts are accessible in auxiliary contact
    Main contact carries high voltage and high current Auxiliary contact carries low voltage and low current
    Sparking occurs due to high current No sparking occurs in auxiliary contact
    Main contacts are main terminal connection and motor connections Auxiliary contacts are utilised primarily in control circuits, indication circuits, and feedback circuits.

    Technical Data

    Standard IEC61009-1 ,  EN61009-1
    Electrical features Rated value UN(V) In (A)
    AC415 50/60Hz 3
    AC240 50/60Hz 6
    DC130 1
    DC48 2
    DC24 6
    Configurations 1 N/O+1N/C
    Rated impulse withstand voltage(1.2/50) Uimp (V) 4000
    Poles 1 Pole (9mm Width)
    Insulation voltage Ui (V) 500
    Dielectric TEST voltage at ind.Freq.for 1 min (kV) 2
    Pollution degree 2
    Mechanical features Electrical life 6050
    Mechanical life 10000
    Protection degree IP20
    Ambient temperature (with daily average ≤35℃) -5...+40
    Storage temperation (℃) -25...+70
    Installation Terminal connection type Cable
    Terminal size top/bottom for cable 2.5mm2  / 18-14 AWG
    Tightening torque 0.8 N*m  /  7 In-Ibs.
    Mounting On DIN rail EN 60715 (35mm) by means of fast clip device

    MCCB Production Line Real Showing

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