Fuse Size Guide report
The IEC standard defines a fuse as a "fuse-link"; it is primarily intended for overload protection. Suppose the fuse is properly placed in the circuit. In that case, when the current abnormally rises to a certain height and heat, the fuse will automatically fuse to cut off the current and protect the safe operation of the circuit.
The fuse, invented by Edison more than a hundred years ago, was used to protect the then-expensive incandescent lamps. With the development of the times, fuses protect electrical equipment from overcurrent and overheating and avoid serious damage to electronic equipment caused by internal faults.
Fuses are very common in everyday life, but selecting these small parts is not as simple as you think. The fuse size must be determined according to various factors, such as circuit, working current, and voltage. If it is too large, it is easy to burn the wires in the home and even cause a fire; if it is too small, it is easy to fuse and cause unnecessary trouble. Here is a helpful fuse sizing guide for you.
Fuse Size Guide
Fuses are basic and simple components of safety devices widely deployed in electrical circuits. Each fuse is a thin metal strip or wire called a resistor that forms a link in an electrical circuit. Many metals are used to make resistors; tinned copper wire is a popular choice. Once the fuse has blown, it interrupts the current flow and becomes an open fuse. Not surprisingly, for such a widely used component, fuses are available in various types and voltage capacities for use in different industrial, manufacturing, and electronic environments.
Fuse Ratings
Fuses are primarily rated in terms of maximum current and how much voltage drop they will safely withstand after interrupting a circuit. Fuses can be designed to blow fast, slow, or anywhere between for the same maximum current level. There are three available principal fuse speeds:
- Ultra-rapid fuses: typically used in sensitive circuitry and transistors to protect against short circuits, reacting almost instantaneously. These are also Very Fast Acting, Super Rapid, and High-Speed fuses.
- Fast Acting Fuses: these are a more general-purpose fuse typically used with cabling and sturdier components. They are also known as Fast Blow or F-Type fuses.
- Slow Acting fuses include a delay mechanism that allows short, lower-power electrical surges to pass through the circuit without the fuse blowing. They are also known as Slow Blow or Time Delay fuses.
Common Fuse Types and Sizes
There are several types and ratings of fuse currently in use in the market, and the table below briefly describes each.
Fuse Type | Size | Voltage Rating | Current Rating | Interrupt Speed |
---|---|---|---|---|
Ceramic Cartridge | 5mm x 20mm | 250 VAC | 0.1 Amp | Fast |
250 VAC | 0.2 Amp | Fast | ||
250 VAC | 0.5 Amp | Fast | ||
250 VAC | 0.63 Amp | Fast | ||
250 VAC | 1.0 Amp | Fast | ||
250 VAC | 1.6 Amp | Fast | ||
250 VAC | 2.0 Amp | Fast | ||
250 VAC | 2.5 Amp | Fast | ||
250 VAC | 4.0 Amp | Fast | ||
250 VAC | 5.0 Amp | Fast | ||
250 VAC | 6.3 Amp | Fast | ||
Pop-up Indicator | 5mm x 25mm | 250 VAC | 0.1 Amp | Slow |
250 VAC | 0.25 Amp | Medium | ||
250 VAC | 0.5 Amp | Medium | ||
250 VAC | 0.8 Amp | Medium | ||
250 VAC | 1.0 Amp | Medium | ||
250 VAC | 2.0 Amp | Fast | ||
250 VAC | 4.0 Amp | Fast | ||
250 VAC | 6.3 Amp | Fast | ||
Ceramic Cartridge | 1/4" x 1-1/4" | 250 VAC | 0.5 Amp | Fast |
250 VAC | 0.5 Amp | Fast | ||
250 VAC | 1.0 Amp | Fast | ||
250 VAC | 2.0 Amp | Fast | ||
250 VAC | 3.0 Amp | Fast | ||
250 VAC | 5.0 Amp | Fast | ||
250 VAC | 7.0 Amp | Fast | ||
250 VAC | 10 Amp | Fast | ||
Glass Cartridge | 5mm x 20mm | 250 VAC | 63 mA | Fast |
250 VAC | 100 mA | Fast | ||
250 VAC | 125 mA | Fast | ||
250 VAC | 200 mA | Fast | ||
250 VAC | 250 mA | Fast | ||
250 VAC | 315 mA | Fast | ||
250 VAC | 500 mA | Fast | ||
250 VAC | 750 mA | Fast | ||
250 VAC | 1 Amp | Fast | ||
250 VAC | 1.25 Amp | Fast | ||
250 VAC | 1.5 Amp | Fast | ||
250 VAC | 1.6 Amp | Fast | ||
250 VAC | 2 Amp | Fast | ||
250 VAC | 2.5 Amp | Fast | ||
250 VAC | 3 Amp | Fast | ||
250 VAC | 3.15 Amp | Fast | ||
250 VAC | 4 Amp | Fast | ||
250 VAC | 5 Amp | Fast | ||
250 VAC | 6 Amp | Fast | ||
250 VAC | 7 Amp | Fast | ||
250 VAC | 8 Amp | Fast | ||
250 VAC | 10 Amp | Fast | ||
250 VAC | 15 Amp | Fast | ||
125 VAC | 6 Amp | Medium | ||
125 VAC | 8 Amp | Medium | ||
125 VAC | 10 Amp | Medium | ||
Glass Cartridge | 1/4" x 1-1/4" | 250 VAC | 100 mA | Slow |
250 VAC | 250 mA | Slow | ||
250 VAC | 500 mA | Slow | ||
250 VAC | 750 mA | Slow | ||
250 VAC | 1 Amp | Slow | ||
250 VAC | 1.25 Amp | Slow | ||
250 VAC | 1.5 Amp | Slow | ||
250 VAC | 2 Amp | Slow | ||
250 VAC | 2.5 Amp | Slow | ||
250 VAC | 3 Amp | Slow | ||
250 VAC | 4 Amp | Slow | ||
250 VAC | 5 Amp | Slow | ||
250 VAC | 6 Amp | Slow | ||
250 VAC | 6.25 Amp | Slow | ||
250 VAC | 7 Amp | Slow | ||
250 VAC | 8 Amp | Slow | ||
32 VAC | 10 Amp | Slow | ||
32 VAC | 15 Amp | Slow | ||
32 VAC | 20 Amp | Slow | ||
32 VAC | 25 Amp | Slow |
Conclusion
A general fuse consists of three parts. The melt is the core of the fuse, and it cuts off the current when it is blown. The melt of the same type and fuse specification has the same material and geometric size, and the resistance value should be as small as possible and consistent; the most important thing is that the fusing characteristics should be consistent. Household fuses are often made of lead-antimony alloys. When choosing a fuse, the following parameters must be attention to normal current, fusing current, open circuit voltage, short circuit current, and inrush current. If you have any doubts, please ask professional sales staff for help.