What are fuses and why do they come in different sizes?
Fuses are devices placed in electrical circuits as protection for those circuits. They consist of small pieces of wire, sometime as ribbons, and are placed in series with the circuit so that the current passing through the device must pass through the fuse. A device that draws, say 1 ampere of electrical current may have a 2 ampere fuse in it. The device works ok unless and until something happens that causes more than 2 amperes to flow through the circuit. At that point, the fuse literally melts, stops conducting the electrical current, and the system shuts down. But suppose we have a device that uses 8 amperes. Then we must use a larger fuse; i.e., a 2 ampere fuse would be no good because it would not allow the device to operate. An air conditioner may use 20 amperes so we would put a slightly larger fuse to operate that. That in a nutshell is why fuses come in different sizes; i.e., we pick a size that fits the job we want to do.
To find out what fuses are and why they come in different sizes, we need to understand how fuses work and their role in electrical circuits.
1. What are fuses?
Fuses are protective devices used in electrical circuits to prevent damage caused by excessive current. They consist of a thin piece of metal, usually a wire or ribbon, that acts as a conductor in the circuit. When the current passing through the fuse exceeds its rated value, the metal melts and breaks the circuit, interrupting the flow of current.
2. Why do fuses come in different sizes?
Fuses come in different sizes, or current ratings, to match the specific requirements of different electrical devices and circuits. The size of a fuse is determined by its current-carrying capacity, measured in amperes (A).
The primary reason for using different fuse sizes is to provide protection based on the expected current draw of the device or circuit they are used in. If a device or circuit draws more current than the fuse's rating, the fuse will blow, preventing excessive current from damaging the electrical components or causing a fire hazard.
When selecting a fuse size, it is important to choose one that matches or slightly exceeds the expected current draw of the device or circuit. If the fuse rating is too low, it may blow unnecessarily, causing frequent disruptions. On the other hand, using a fuse with a rating higher than necessary may create a safety hazard because it doesn't provide adequate protection.
For example:
- A small electronic device may have a low current draw, so it would require a smaller fuse, such as 1 or 2 amperes.
- A medium-sized appliance like a refrigerator may have a higher current draw, so it would require a larger fuse, such as 10 or 15 amperes.
- A high-power device like an air conditioner may have an even higher current draw, so it would require a much larger fuse, such as 20 or 30 amperes.
By using fuses of appropriate sizes, we ensure the electrical system's safety by preventing excessive current from causing damage while allowing normal operation.