Fuses are safe and effective, and while locating problems with the wiring is simple, it still may be a little time consuming. Although fuses may no longer be a part of modern home wiring circuit protection, they are still a safe and effective device for protecting lights and appliances. When a fuse does burn out it generally indicates that there is a problem. In most instances it seems that fuses burn out at the most inconvenient times. This is why you should always have spare fuses on hand in a ready location for replacement. A burned out fuse is generally easy to identify. A small glass window distinguishes whether or not a fuse is good. When a fuse burns out or blows, the glass is covered in a dark black color. Fuse replacement is typically a simple task of screwing the old one out and inserting the new one. This operation is mainly for all 120-volt alternating current or 120-vac circuits. If you are not sure about the condition of the 120-volt fuse, you can test it by following the method described for the 240-volt type fuses. The 240-vac fuse is generally cylindrical in shape and has no see through indicator to show you it has burned out. You must test the fuse to find which of the two fuses needs replacing. A simple volt ohmmeter, or VOM for short, is a wonderful inexpensive tool that no home should be without, especially a home that has fuses for its circuit protection. The test for checking the fuse is quite simple. First, you must pull the fuse socket from its receptacle on the main panel board. There should be a metal handle attached to the plastic fuse holder. A strong pull is required to remove the holder from the panel's contacts. Do not remove the fuses from the holder yet, as you do not know which fuse is bad. Follow the manufacture instructions on the volt ohmmeter for setting the meters switch to ohms, and place the leads to the separate ends of one fuse. If the meter indicates continuity then the fuse is good. If the meter shows that an open has occurred, then you should replace the fuse. Never, under any circumstances, check a fuse for continuity while it is still energized. This practice is very dangerous and can lead to a severe burn or a fatal shock. Once you replace the fuse, return the socket to its receptacle with a firm push. The circuit should now be delivering power. In most instances of a fuse burn out, an appliance or circuit was drawing too much power and the fuse did its job in protecting the circuit. If the fuse blows again then you may have either a wiring problem or a faulty appliance. Follow the easy steps below for any type of electrical circuit to determine if you have either of the described problems. 1. Pull the fuse socket and thoroughly inspect the wiring on the load side of the fuse. The load side wiring is the wires that lead to the house appliance or circuit. Be sure, to check with the voltmeter, to see if the circuit is truly off. Then check the wire connections on the screw terminal that holds the circuit wire in place. Many times overheating of the circuit can occur and loosen the wires. If the wires are tight, check the remainder of the load side wiring. 2. There could be a problem with the receptacle outlet, appliance, or lighting circuit, which is causing the fuse to blow. Unplug or disconnect the device and check the circuit. Now with everything pulled from the load side of the circuit, replace the fuse to the receptacle. You can check the receptacle outlet by inserting the leads of the voltmeter into the slots of the receptacle, following the voltmeters manufacture instructions. If the fuse delivers power to the outlets, the appliance is faulty. If the meter does not read power, then you blew another fuse. The problem is more than likely in the wire itself or on the wire connections to the outlet receptacle. 3. If a lighting circuit is on the system, shut the switch off and unscrew the bulb. For testing the lighting circuit, if you still have the light bulb pulled from the socket, turn the switch on. Then check the fuse again to see if it is still good. If the fuse blew, then you have a wiring or connection problem in the switch. If the fuse was still okay, turn the switch off, replace the light bulb into the socket and turn the switch on. If the light turns on your problem is solved, if not, there is a problem in the wiring, leading from the switch to the light or in the light fixture itself. By following a simple method of tracing the circuit from the source to the loads, any electrical problem can be solved. It may take a little time and a couple of fuses, but eventually you will find the problem by staring at one end of the circuit and continuing down its path. No special skills needed. Tools Screwdriver.