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Installation method of low voltage circuit breaker

By:Nader Updated:September 09,2020 11:31AM

The installation methods of low-voltage circuit breakers are divided into: fixed, plug-in and withdrawable.

  1. Fixed type: Fix the circuit breaker on the installation board of the complete set with mounting screws. Because the connecting wire must be removed when replacing the circuit breaker, the replacement of the circuit breaker takes a long time and is troublesome.
  2. Plug-in type: mainly suitable for plastic case circuit breakers, divided into front-board wiring and back-board wiring. On the installation board of the complete set, first install a circuit breaker mounting seat (there are 6 plugs on the mounting seat, and there are 6 sockets on the circuit breaker connection board). When using, first insert the circuit breaker directly into the mounting base, and then fix the circuit breaker on the mounting base with mounting screws. If you need to replace the circuit breaker, first remove the mounting screws and then pull out, then replace it. Because there is no need to remove the connecting wire when replacing, it is faster and more convenient than the fixed type. The plug-in type requires a certain amount of external force during insertion and extraction. Generally used for circuit breakers whose frame current does not exceed 400 A.
  3. Withdrawable type: Mainly suitable for universal circuit breakers and plastic case circuit breakers with frame currents above 400 A. Place the circuit breaker gently on the installation table, insert a rocker into the hole of the installation table, and rotate it clockwise. With the worm gear engaged, the circuit breaker gradually comes into close contact with the terminal block of the installation table; if taken out, Just turn the joystick counterclockwise. The drawer type has three positions of contact, separation and isolation (the circuit breaker is not energized), and the plug-in type has only two positions of contact and separation, so the drawer type is safer and more reliable when replacing the circuit breaker than the plug-in type.

Regardless of the installation method, it has been verified during the product type test and production process and meets the requirements of GB 14048-2. The circuit breaker can work normally under the specified conditions of use.

Choose installation method according to operating experience

The circuit breaker we selected in the design is a complete set of products that the switch manufacturer has assembled the circuit breaker in the switch cabinet or distribution box. Whether the circuit breaker is installed vertically or horizontally, the design is not too big Opinions, only need to use the unit operation operator based on operating experience, put forward the installation requirements of the circuit breaker when ordering the product. If the drawer type switchgear circuit breaker is selected in the design, it is generally installed horizontally, one side (left) incoming line is connected to the circuit breaker bus, and the other side (right side) outgoing line is connected to the load line. The problem to be considered is that if the electrical load capacity of the withdrawable circuit breaker is large, heat dissipation needs to be considered. According to the manufacturer, the temperature of the thermal release of the circuit breaker is generally set at 30 ℃. If the ambient temperature exceeds this value The coefficient of repair should be considered, or another grid should be used for another outlet to avoid the mutual influence of temperature rise.

Pay attention to the installation direction of the circuit breaker

I don’t pay much attention to the installation of the circuit breaker. The panel factory engineers are more interested in this topic. Of course, the correct installation of the circuit breaker will definitely have a lot to do with the realization of the designer’s vision and the stable running time in the future. The suggestion to the designer is that the installation direction of the circuit breaker's incoming line has a certain influence on the operation of the circuit breaker. The larger the volume and weight of the circuit breaker, the greater the effect of gravity on the breaking capacity. When the circuit breaker is designed, the fixed contact is on the upper part of the circuit breaker, the moving contact is on the middle, and the tripping part is on the lower part, so that the arc extinguishing cover and the main contact point are also arranged on the upper part of the switch, so the upper wire can reduce the heat of the terminal. Influence of heat conduction on the trip curve. The MCCB with residual current protection action function is strictly prohibited from entering the wire from the bottom. There are related instructions in our product catalog. In the case of lower incoming line, the leakage protection function will be lost.