What are the differences between load switches and circuit breakers

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

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

The circuit breaker can turn 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 remove short-circuit faults under the action of the protection device. It can deal with current (rated current) and voltage (the insulation level of the fracture is higher than that of the circuit breaker, but lower than the isolating switch), but although the load switch can open and close the rated current, close the short-circuit current, it is strictly forbidden to open the short-circuit Current. Because 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 sub-river operation) Circuit breaker-with protection (except for the above, can break the accident current) Isolating switch-for isolation (can not be operated with load)

Fuse-protection element (can break the accident current)

The main difference between circuit breaker and load switch

The circuit breaker can cut off the working current and the accident current.

The load switch can cut off the working current but not the accident current.

The isolating switch cannot cut off any current. It can only be opened and closed when there is no current.

From a traditional perspective, load switches and circuit breakers are very different. Load switches are mainly used to break and close load currents. Load switches can be used in conjunction with high-voltage fuses to replace expensive circuit breakers and cut off fault currents, that is, short-circuit currents. In this way, it also determines the off-load switch. The arc function is relatively weak, which reduces the manufacturing cost; it is precisely because the traditional load switch is not used to cut off the fault current, there is no need to connect with the protection device and the automatic device, so most load switches are manually operated and cannot be operated by electric power. When the circuit breaker is designed, it is considered not only to be able to break and close the load current, but also to cut off the short-circuit current after a fault. It must be connected to the protection device and the automatic device, so it has manual and electric closing and opening. Gate function. However, in modern times, especially with the introduction of foreign technology, load switches are made more and more like circuit breakers, and individual load switches have increased arc extinguishing capabilities and increased electric operation functions.