# Investigating Fuses: Explaining Why They Melt

• O_oSam
The thermal conductivity of the fuse material also plays a role in dissipating the heat. The thermal expansion of the wire is not directly relevant in this scenario. In summary, the conversation is about a missed Physics project deadline and the use of fuses in a circuit. Fuses melt due to the heat generated in them, which is influenced by factors such as resistivity and thermal conductivity. The thermal expansion of the wire is not significant in this case.
O_oSam
I have just started a Physics project which I have already missed the deadline for >_<

I have a very minimal set of results, I basically took a power supply>smoothing unit and put them in a circuit with a component holder and two resistors (in parrallel so I didnt blow the ammeter) and took readings.

Was wondering if I could get some helpful information etc. on fuses. Can anyone give me a detailed explanation of why fuses melt, I was hoping to tie in Electrical resistivity [I'm aware it changes as fuse heats] and possible thermal conductivity?

Does the thermal expansion of a wire have any relevance?

Thanks

Sam

Im not sure if I should tell you this, because its obviously something you should do yourself.

Fuses melt because the heat generated in them increases the temperature of the fuse wire beyond the melting point. The heat generated is equal to $$dh=i^2Rdt$$ and R is related to resistivity by the expression $$R=\rho \frac{l}{A}$$, where A is the cross sectional area, $$\rho$$ is the resistivity and l is the length of the wire under consideration.

## 1. Why do fuses melt?

Fuses melt due to an overload of electrical current. When the current flowing through a fuse exceeds its rated limit, it generates heat, causing the fuse to melt and break the circuit, preventing damage to the electrical system.

## 2. How do you determine the melting point of a fuse?

The melting point of a fuse can be determined through experimentation. By gradually increasing the electrical current flowing through the fuse and measuring the temperature, the point at which the fuse melts and the circuit breaks can be determined.

## 3. What materials are used to make fuses?

Fuses are typically made of a metal with a low melting point, such as copper, silver, or aluminum. The metal is encased in a non-conductive material, such as glass or ceramic, to contain the heat and prevent fires.

## 4. Can fuses be reused?

No, fuses cannot be reused. Once a fuse has melted and broken the circuit, it must be replaced with a new fuse. Attempting to reuse a melted fuse can be dangerous and may result in electrical fires.

## 5. What are the benefits of using fuses in electrical systems?

Fuses are an essential safety feature in electrical systems. They protect against overloading and short circuits, preventing damage to the electrical system and potential fires. They are also relatively inexpensive and easy to replace.

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