To replace a blown fuse, unplug the appliance that is the cause of the problem, locate the blown fuse, unscrew the fuse, and replace it with an exact match. When working with a fuse box, it is essential to have dry hands and stand on a dry surface.
Fuses blow because the circuit is overloaded, there is a ground fault or there is a short circuit. Without fixing the underlying cause of the blown fuse, it blows again. As the number of electrical appliances operating in the average home today may be greater than was common at the time of the home's construction, many circuits are overloaded. The solution is finding another circuit to power the appliance or updating the wiring to meet current needs.
One method of determining the cause of the blown fuse is unplugging all the appliances from the circuit and turning off the lights before replacing the fuse. If the fuse blows with no appliances or lights, the problem is in the wiring. The next step is turning on the lights one at a time to determine if a light is the problem. If the lights are not the problem, the final step is plugging in each appliance individually to determine the one causing trouble. When the problem-causing appliance is identified, it should be removed from service, then replaced or repaired.