Replace a Fuse in 6 Steps

Before you ever have to change a fuse, check your breaker box and determine what types of fuses, if any, it uses. Most modern breaker boxes do not use fuses, but use amp-rated circuit breakers instead. If one of these trips, you can reset it by turning that breaker off and back on again. If the panel does require fuses, find out what type and what amperage rating. Pick up spares before you need them. For replacing glass bullet-shaped fuses, follow the six easy steps below.

Step 1 - Open the Fuse Box

First turn off appliances or lights in the affected area. Open the door of the fuse box. Since fuses are meant to be replaceable, you can usually accomplish the task by simply opening the door. If you cannot access the fuses from this position, you may have to use a screwdriver to remove the front cover.

Step 2 - Identify the Blown Fuse

The blown fuse should have a burnt or darkened area in the center of the flat fuse face. If you cannot tell which fuse has blown, and they are not listed in the panel, you may have to remove the fuses one at a time to find the correct one. If so, label the fuse box as you go to avoid future confusion.

Step 3 - Replace the Fuse

Unscrew and discard the old glass fuse. If your fuses are cylindrical box-fitted fuses, you will have to pull out the box in order to check the fuses. You may also need a fuse puller to swap out the old fuse for the new one. Follow the exact opposite procedure to put in the new fuse.

Step 4 - Replace the Cover

If you had to remove a cover to access the fuses, do not replace it until you have changed the fuse and verified power to that circuit. Always replace or close the cover when you complete the work to avoid objects causing a fire or electrical short by accidentally getting into the fuse box.

Step 5 - Identify the Cause

Once you have replaced the fuse, try to identify why it blew. Commonly a fuse will burn out if too many electrical items are connected to the circuit and overload the fuse's capacity to supply amperage. Remove some of the power demands from the circuit. Fuses will burn out naturally over time, but if you must replace the same fuse frequently, and the circuit is not overloaded, you may have a more serious problem.

Step 6 - Troubleshoot the Circuit

If the same fuse burns out twice in less than a month, troubleshoot the circuit for possible problems in the wiring. Begin by removing all loads from the circuit, and wait to see if the fuse still burns out. If it does, test your wiring circuits with a multimeter. Check for proper voltage, amperage, and resistance. Make sure there is not any obstruction in the fuse socket, and that the fuse is able to seat solidly.