Electricity is paramount for powering the countless appliances and electronics that we rely on every day, but it is also a volatile force that needs to be managed for safety. When an excessive amount of current passes through wires due to a short circuit, a great amount of heat may be generated and sensitive components can be seriously damaged. Additionally, short-circuiting can even cause electrical fires and dangers to individuals which can be extremely dangerous for certain applications such as aviation. In order to prevent the damages and hazards associated with overload conditions, electrical circuits are guarded with circuit protection devices. The most common circuit protection devices are fuses, current limiters, and circuit breakers. As each device type has its own features and capabilities that dictate their use, it can be very beneficial to understand the differences between each.
Fuses are a basic component for circuit protection, and they are a thermal device with an element which exhibits a low melting point. Fuses generally have low current carrying capacities, and they are designed to melt in the occurrence of a short circuit. With this method of operation, fuses can quickly interrupt a circuit for safety. The element of the fuse may be constructed from varying materials, and the most common are lead silver, tin, bismuth, and their related alloys. To provide ample protection for the circuit, fuses must be placed near the power source so that they may manage the entire cable. For aircraft applications in particular, fuses are often heavy-duty and may serve AC and DC sources. Furthermore, aircraft often employ fuses for both the circuit and devices for redundancy and further protection.