Fuses and circuit breakers are common protection equipment in the power system, their role is to cut off the current in the circuit when anomalies occur in order to protect the safe operation of power equipment and systems. However, although they have a common goal, but the fuse and circuit breaker in the working principle and structure there are some obvious differences.

1, The working principle is different

The working principle of the fuse is mainly based on the thermal effect of the current. In the current exceeds the fixed value, its internal fuse will melt so as to achieve the circuit breakers, to protect the equipment will not be burned by the role of high current.

Circuit breakers are much more complex, but basically rely on the solenoid, the solenoid with the increase in current and magnetization and pull the contacts open, thus achieving the same purpose. Of course, circuit breakers can be operated not only automatically but also manually by controlling the breaking and closing action of the circuit breaker.

2, The protection mode is different

The protection mode of the fuse is used in the form of fusing. After eliminating the fault, you need to replace the fuse to restore power supply, so the maintenance is not very convenient.

Circuit breaker protection is used in the form of tripping. After eliminating the fault, only through the closing action can restore normal power supply, so in the maintenance and recovery will be much more convenient than the fuse.

3, Action speed is different

Fuse action speed can reach microseconds (μs) level, that is to say, its speed compared to the circuit breaker to speak on a lot faster, this ability is usually more suitable for similar rapid cut-off requirements of the occasion for installation and use.

Circuit breaker tripping action speed is milliseconds (ms) level, which can be seen than the fuse is much slower, so it can only be applied to the interrupting speed requirements are not very high occasions for use.

Fuses and circuit breakers have very similar functions – both cut off circuits in the event of a current surge or short circuit. However, there is a key difference. Circuit breakers are switches and, like all switches, can be put back into service once cut. Most fuses, on the other hand, can only be used once. Once they blow, they must be replaced. By design, this is one of their weak points.

Fuses are inexpensive and can be replaced quickly and easily with little downtime. It is important to install the correct current rated, fully compatible type for the equipment. Fuses are more sensitive than circuit breakers.