A fuse panel is a part of an electrical system which is designed to divide a source of electricity into an assortment of circuits, each of which is protected from overcurrent by a fuse. These panels are also known as fuse boxes or fuse blocks, depending on the application, and they can be found in association with a wide variety of electrical systems. One very common form is the automotive fuse panel in vehicles, which handles the electrical supply in a car or truck.
Fuses provide protection from overcurrent by failing when there is too much current or the fuse gets too hot. When the fuse fails, the circuit opens, and is no longer able to conduct electricity. Fuses which have failed are said to have “blown” and they must be replaced to re-energize the circuit. When fuses blow, it protects devices on the circuit from overcurrent, and reduces the risk of fire and other electrical problems caused by overcurrent.
In structures, the fuse panel is located near the service drop, the site where electricity is fed from the grid or a power generating system into the structure. The panel breaks the feed up into dedicated circuits of varying voltages, depending on which devices are connected to those circuits. In vehicles and boats, fuse panels direct the power from the battery.
Ideally, when a fuse panel is installed, an electrician will create a wiring diagram which clearly labels each of the circuits in the panel and diagrams the wiring which extends from the panel to various locations. In cars, there is often a fuse panel diagram on the door of the panel, so that when drivers experience an electrical problem, they can immediately find the fuse involved. Labeling is also important because it allows people to safely turn off desired circuits.
When a fuse blows, it is important to determine why the overcurrent occurred. If the fuse is simply replaced with a new fuse, the new fuse may blow again because the issue has not been resolved. Fuse panels themselves also need to be regularly inspected for signs of problems, and they may need to be upgraded and replaced periodically to cope with changing needs. Using a fuse panel which is not rated for the application it is being used for can be extremely dangerous, and the fuses in the panel may fail to act as they should.