Fuses and circuit breakers are, in a nutshell, devices that protect assets and equipment that are hooked up to a working power grid. Their basic function is to break the circuit between the equipment and the power grid in the event of something that could cause damage to either. These include a short circuit, a ground fault, and a power overload.
How do they work?
While fuses and circuit breakers practically have the same functionality and purpose, the way in which they perform their main function makes them different.
A fuse works by completing the circuit between the power grid with a piece of conductive wire that has a very low melting point—i.e. it melts very easily. Should the current of electricity flowing through the circuit get high enough that it starts to get very hot, the wire inside the fuse melts, breaking the circuit and thus cutting off the power. The fuse is now ‘blown’ and needs to be replaced.
A circuit breaker, on the other hand, works by completing the circuit with two kinds of metal, one of which expands much more quickly than the other when exposed to hot temperatures. Like with what happens with the fuse, should the current become too much that it starts to heat up, the metal reacts by expanding and bending out of alignment with the other metal, thus breaking the circuit.
Unlike the fuse, however, a circuit breaker can be reset once it’s been tripped, either manually or automatically, and can also serve as a hard on/off switch for the entire house or workplace should there be a need to cut off all power. A variant where an electromagnet is used to break the circuit whenever the current gets too high also exists.
What can make a fuse ‘blow’ and a circuit breaker ‘trip’?
The following faults can blow a fuse or trip a circuit breaker:
> Overload. An overload occurs when there are way too many appliances hooked up to the power grid. As such, there is too much power being drawn into the circuit to accommodate for the heavy demand. This could cause damage to the wiring inside your home or place of business as they are only rated to handle up to a certain amount of electric current and could spark or burn up into flame as a result.
> Short circuit. A short circuit occurs when something happens to the circuit that makes the current in it behave abnormally and travel in unintended directions, such as when wiring gets frayed enough that the two wires—the hot wire and the neutral wire—touch. A faulty appliance can also be a cause of this. Like an overload, this can cause electrical fires stemming from either the wiring or the appliance involved in the short circuit.
> Ground fault. A ground fault is a type of short circuit that happens when the ‘hot’ wire comes into contact with anything metal that’s not supposedly part of the circuit, such as when frayed wiring comes into contact with the metal box housing it. This causes the current to drain somewhere else and can potentially cause an electrical fire, just as a short circuit could.
Fuses and circuit breakers protect your property from damage by preventing the above events from turning into electrical fires whenever they occur. This is why they’re so important and should never be neglected. Make it a habit to check on your fuses and circuit breakers regularly.
Which should I get for my home or commercial property?
Ideally both, especially if you have important or expensive appliances that are required to be hooked up to electricity most of the time (refrigerators, computers, servers, etc). Investing in other protective measures such as surge protectors is optional, but it is also recommended as they add another layer of security against electric damage.
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