What is a fuse?
Fuses are a type of over-current protection device. The essential component is a metal wire or strip that melts when too much current flows, which interrupts the circuit in which it is connected. Short circuits, overloads or device failures are often the reason for excessive current.
A fuse interrupts excessive current (blows) so that further damage by overheating or fire is prevented. Over-current protection devices are essential in electrical systems to limit threats to human life and property damage. Fuses are selected to allow passage of normal current and of excessive current only for short periods.
Fuses serve two main purposes:
1. To protect components and equipment from costly damage caused by over-currents.
2. To isolate sub-systems from the main system once a fault has occurred.
There are thousands of different styles of fuses available in the world. The primary way to group them is by Low Voltage (Voltage Rating less than or equal to 1500V) or Medium Voltage (Voltage Rating between 1500V and 40.5kV).
All fuses are designed to open a circuit to protect other valuable components from over-currents. However, they are not all designed to do it in the same way!
There are many different types of fuse performance options and selecting the correct performance for your application is vital. For this purpose, the IEC created 'Utilisation Categories' which define the performance characteristic of a fuse.
A fuse is a type of over-current protective device that is designed to be a sacrificial element in an electrical power system. Fuses are designed to open circuits when excessive over-currents are present and are designed to prevent further damage to the system that might result if the fuse were not present. The use of fuses in a circuit provides cheap insurance should there be an accidental or unintentional fault in the system wiring or components. Low voltage fuses are very common in electrical systems and they come in diverse styles, shapes and sizes. Low voltage fuses are defined as fuses with a voltage rating less than or equal to 1,500V. > Learn more
Medium voltage fuses are defined as fuses with a voltage rating greater than 1,500V and less than or equal to 36,000V (36kV). MV fuses are primarily used for the protection of transformers, motors, CT's and VT's. They are very common in electrical systems and they come in diverse styles, shapes and sizes. The most common styles in Australia & NZ are DIN style, British Standard Air and British Standard Oil type. MV fuses are available in three IEC performance categories: Back Up, General Purpose and Full Range.> Learn more