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What are the differences between load switches and circuit breakers?

Switches are often used in life, and there are two major types of switches, load switches and circuit breakers, both of which can connect circuit power and cut off circuit power, but circuit breakers have overcurrent and overload protection functions. The following is a detailed introduction to the difference between the two.

The load switch refers to a control appliance that has a simple arc extinguishing device and can be equipped with a load switching circuit. It can make and break a certain load current and overload current, but cannot cut off the short-circuit current. It must be used in series with a high-voltage fuse and cut off the short-circuit current with the help of the fuse. Specially deal with current (fault current, rated current), the insulation level of the circuit breaker fracture is very low, so the ability to deal with overvoltage is very weak. The switch specially for dealing with voltage (the fracture insulation level is very high, which can deal with very high fracture withstand voltage value) is an isolating switch, commonly known as a knife gate, the isolating switch can not deal with any large current, rated current and short circuit current, can cut small current circulation .

The circuit breaker can switch on and off the circuit under load. When the system has a short circuit fault, it can quickly cut off the short circuit current. It can also automatically cut short circuit faults under the protection device. Can deal with current (rated current), can deal with voltage (fracture insulation level is higher than the circuit breaker, but lower than the isolation switch), but the load switch can break and close the rated current, close the short circuit current, but it is strictly forbidden to break the short circuit Current. Since the load switch cannot break the short-circuit current, a fuse must be installed to provide remote backup protection.


Load switch-without protection (only with rated load for diversion operation) Circuit breaker-with protection (except for the above, it can break the accident current) Isolation switch-plays an isolation role (can not be operated with load)
Fuse-protection element (can break accident current)
The main difference between circuit breaker and load switch
The circuit breaker can cut off the working current and accident current.
The load switch can cut off the working current but not the accident current.
No current can be cut off by the isolating switch. It can only be opened and closed when there is no current.
From a traditional perspective, load switches and circuit breakers are very different. The load switch is mainly used for breaking and closing the load current. The load switch can be used in conjunction with a high-voltage fuse to replace a high-priced circuit breaker to cut off the fault current, that is, the short-circuit current. The arc function is relatively weak, which reduces the manufacturing cost; precisely because the traditional load switch is not used to cut off the fault current, there is no need to connect the protection device and the automatic device, so most load switches are manually operated and cannot be operated electrically. When designing the circuit breaker, it is considered that not only can it break and close the load current, but also be able to cut off the short-circuit current after the fault, it must be connected to the protection device and the automatic device, so it has manual and electric closing and dividing Brake function. However, from a modern point of view, especially with the introduction of foreign technology, load switches are manufactured more and more like circuit breakers. Individual load switches have increased arc extinguishing capabilities and increased electric operation functions.

Date:2019-09-07 11:25

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