Why Choose Fuses or Circuit Breakers

Most of you have installed fuses as well as circuit breakers. However few electricians know why each is chosen. Fuses are composed of a casing, usually glass, and a conductive core. This conductive core material varies depending on the application. Fuses allow a certain amount of current to flow across the conductive core until it reaches a predetermined level. Once this level is reached, depending on if it is a time delay fuse or not, the fuse blows. When a fuse blows the conductive core melts in two. This renders the fuse useless and in need of replacement. Fuses work regardless of ambient temperature. Here in lies the main difference. Circuit breakers have two main working principles. The first type of circuit breaker relies on an electromagnetic section to break the circuit and stop the flow of electricity. The second type of circuit breaker has a bi-metal blade that, when the current reaches too high, bends away from the terminal points and breaks the circuit. Both types of circuit breaker rely heavily on ambient temperature to function correctly. Circuit breakers can protect against short circuits as well as overloads. Whereas fuses only protect against overloads. Installed on many control panels will be a means of temperature control. This is correct ambient temperature issues with the circuit breakers located inside. Fuses are inherently useful for extreme temperature installations as well as time-controlled overload currents. However circuit breakers are reusable, not requiring replacement, after tripping. Hopefully next time you have to make the selection between fuses or circuit breakers you are more knowledgeable of the differences between the two.