Resettable Fuses
Resettable fuses or thermal device circuit breakers, are designed to trip during a short circuit or overload to protect components and equipment from electrical faults. The tripping element is a bimetal strip made of steel and zinc and an electrical heating element. When exposed to an overcurrent, one metal expands faster than the other causing the bimetal strip to snap open. The spring-loaded contact mechanism is tripped and the flow of current is halted.
Thermal device circuit breakers come in three types of reset methods. Type I resets automatically after the bimetal strip cools. If the overcurrent is not removed, the breaker will continue to cycle on and off until the cause is corrected. Type II is non-cycling and will not reset until the until the overcurrent is removed or the power is shut off. Type III is reset manually by an external button or lever.
Resettable fuses vs Traditional fuses Traditional fuses completely stop the flow of current after they have been blown and must be replaced. Resettable fuses may still allow the equipment to operate, except in extreme cases. Because they reset automatically, they are a better choice for applications where overcurrent events are expected to occur more often or for circuits that are difficult to access or may be in remote locations.
