Circuit Breakers are mechanical devices that involve a magnetic solenoid and a bimetallic strip inside. When the strip heats up (due to current), it bends and activates the solenoid – which in turn trip the circuit breaker and stop the flow of power.
Fuses (on the other hand) are components existing of insulating material with a filament in the middle of it. When the fuse heats up (due to current), the filament will break. Thus breaking the flow of electricity in the circuit.
There are noticable differenses between circuit breakers and fuses:
Fuses are less expensive than circuit breakers.
Fuses needs to be replaced when it blows. Circuit breakers have the advantage of being able to reset the breaker when they trip once the fault has been cleared.
Fuses typically react very quickly to overcurrent whereas a circuit breakers will take a bit longer to react.
Fuses are quicker to react which is nice for sensitive electronics.
Fuses have a disadvantage of being single use, which can lead to either being out of fuses or selecting the wrong type of replacement fuse.
Fuses usually blow more often on circuits that might have high inrush currents on startup.
Selecting a fuse or circuit breaker all depends on the application you are using. If you have something that requires high sensitivity you might prefer fuses, whereas if you have high inrush current you will choose circuit breakers.
It can also depend on ground fault or arc fault applications, which would generally be protected by a circuit breaker. Mostly because you can choose between slow blow and quick blow fuses. They can also have different types of filaments inside that allow them to react differently. Not all fuses are created equally, there are specialty fuses for special applications such as drive fuses or ac or dc fuses only.
With breakers, you can have multipole breakers, arc fault, and ground fault breakers, as well as adjustable trip units within the breaker which allows you to dial in the breaker for your application.
Breakers also have different trip curves. You want to ensure that you’re selecting the right type of curve. When looking at the curves you will see a multiple of current along one axis and time along the other. When reading the curves, it will show how long a breaker can withstand current before tripping. This can be important to make sure you select the right type of breaker for the application such as high inrush on a motor so that you don’t trip the breaker too soon and cause nuisance tripping or taking down a whole line unexpectedly.
Selecting the right type of protection for the circuit is important to ensure that in the event of some type of overcurrent (or other unintended means of operation) that the device you selected reacts the way it should to make sure that the circuit is removed from power. At the end of the day, it’s important to select the right type of breaker or fuse to ensure the safety of everyone involved.
Contact us at Amped Electrical Suppliers in Vereeniging for your circuit breaker and fuse needs.