Compare and contrast a circuit breaker and a fuse?

Answer 1

A circuit breaker is something you can reset. When the switch "trips", the position of the switch goes to the middle. To reset it, move to Off, then On.

When a fuse blows, its two external contacts are no longer connected by the internal piece of fuse wire and an electrical current can no longer flow.

More technical details about fuses

In all types of disposable fuse, two contacts which are on the body of the fuse are connected to a piece of fuse wire inside. The material used to make the fuse wire, and its thickness, designed to melt - and thus break the circuit - if the current flowing through it exceeds a certain amperage, which is known as the fuse's "maximum rated current".

There are many different types of disposable fuse: some are screwed into what looks like a light bulb socket.

Other types are small tubes - made of glass or ceramic - with a metal contact at each end. They are held in a fuse holder that has contacts, clips or springs which make contact with each of the fuse's end contacts.

Some commonly used automotive fuses are made of plastic and have two flat metal "pins" which plug into a pair of contacts in the fuse box.

Answer 2

Compare:

both interrupt current

both have limitations on how much can be interrupted

contrast:

fuse operates once, circuit breakers can be reset

breakers are more complex than fuses

breakers are more expensive than fuses

Answer 3

Both circuit breakers and fuses are safety devices meant to prevent catastrophic damage when there is an overcurrent condition in an electrical circuit. One example would be in residential wiring: if there is too great a load on a circuit (perhaps the homeowner plugs too many things into a single outlet), we would rather have the circuit breaker or fuse "pop" than to have the wiring in the wall overheat.

There are several differences between a circuit breaker and a fuse. For the end user (such as a home owner), the most noticeable difference is that a circuit breaker can be reset while the fuse must be replaced after each overcurrent event. Other differences include cost (circuit breakers generally have greater initial cost but may be cheaper over the lifetime of the circuit) and trip characteristics (ordinary fuses generally trip more quickly, which may or may not be a good thing).

These differences arise because fuses and circuit breakers operate on different principles. The simplest fuses contain a thin piece of wire that melts from resistive heating when too much current flows through them. Circuit breakers often use resistive heating, too, but these devices generally contain bimetallic strips that change shape temporarily and can be reset. This type of circuit breaker takes much longer than a typical fuse to react to an overcurrent condition, so it can be useful for inductive loads like motors that cause a surge of current when they are first turned on. They are less useful for sensitive electronics or when there is danger of electric shock. Another type of circuit breaker uses a magnetic actuator to trip in an overcurrent condition: these can sometimes be faster than a fuse and are suitable for sensitive electronics. Either kind of circuit breaker is more complicated than a fuse, so they typically cost more; however, you may save money in the long run because a circuit breaker can be reset many times.

Answer 4

Fuses and circuit breakers are both overcurrent protection devices, which will disconnect a circuit in the event of a prolonged overload current or in response to a short circuit.

Fuses operate due to the heating effect of an electric current, by melting in response to the overcurrent. The speed of operation depends on the level of overcurrent.

Circuit breakers operate due to both the heating effect and the magnetic effect of an electric current. The heating effect protects against overload currents, and the magnetic effect protects against short-circuit currents.

Answer 5

The circuit breaker preforms three functions where as a switch disconnect preforms one. A breaker will automatically disconnect the load if a short circuit fault occurs or if there is an overload condition on the conductor caused by the load. The third function is that a breaker can be used as a manually disconnect to isolate the load. Where as a switch's only function is to just isolate the load from the supply system.