Although many homeowners switched their electrical panels over to a breaker box, many home still contain fuse boxes. These fuse boxes rely on fuses in order to prevent power overloads and short circuits. If any issues occur, the result may be a blown fuse. To help identify, address and avoid blown fuses, here is some general information.
How to Tell If A Fuse Has Blown
It will be pretty obvious to you right away if you have blown a fuse in your home, as the switch you’re trying to flip, or the outlet you want to use, or even the appliance you’re trying to run, stops working or won’t turn on. You may also suddenly find yourself in the dark.
If you suspect you have blown a fuse, you can also go and look directly at your fuse box. Frequently, a blown fuse means bits of melted metal inside the fuse or discoloring in the glass window at the top of the fuse. If you’re still unsure if you’ve blown a fuse, you can try replacing the suspected damaged fuse with one you know is working correctly and if power is restored, then your problem is solved. Another way to test for a blown fuse is to use a tool called a multimeter, and connect the fuse to the multimeter to check for resistance. If there is resistance showing on the reader, the fuse is blown, and if no resistance registers then the fuse should still be good.
What Causes a Blown Fuse?
There are a couple of reasons a fuse is blown, including:
Electrical overload. Overloading the circuit occurs when too much power draws on a single circuit. For example, avoid running your dishwasher and dryer on the same circuit because they both use high amounts of power. If this occurs, you could easily cause a circuit overload. When the circuit overloads, the metal ribbon within the fuse will melt, causing the electrical connection to open. As a result, the power stops. A qualified electrician calculates and wires safe loads for your fuse box.
Short circuit. This occurs when electrical components accidentally touch or cross. This can occur anywhere along the circuit, from the wiring within your house, to the power cord of a device itself. To fix, you must isolate and identify the circuit containing the blown fuse. Next, check for any shorts by tracing the entire length of electrical wiring on that circuit. A qualified electrician can also perform this task.
You must replace a fuse after it has blown in order to restore power, as the fusible link within the unit has melted, eliminating the connection that completes the circuit and allows power to flow.
Types of Fuses
There are two main types of fuses commonly used in homes today. They are plug fuses and cartridge fuses. It’s a good idea to keep spare fuses on hand in case one blows.
Plug fuses feature a screw-in design and a glass window that lets you quickly see if a fuse has blown or not. They typically come in 15, 20, or 30 amp sizes and frequently used to protect 120-volt circuits. The cost of a plug fuse is typically around $2-$5, and will depend on amperage.
Cartridge fuses are cylindrical in shape and have contacts on either end that plug into the fuse box. They are frequently used to protect 240-volt circuits and often require a special tool called a fuse puller in order to be replaced. The cost of a cartridge fuse is anywhere from $10-$200, depending on specifications.
How to Replace a Blown Fuse
Replacing a blown fuse is actually a very easy task, and one that any homeowner can reasonably do themselves. The first step in replacing a blown fuse requires you to check the amperage rating of the fuse you need to replace. Newer fuse boxes contain a built-in safeguard, which allows you to screw in the correct sized fuse. Plus, this helps prevent electrical fires.
After ensuring that the device that may have tripped the fuse is unplugged or turned off, you’ll next need to unscrew the blown fuse (or pull out the cartridge), removing it from the fuse box. Take the new fuse out of the package and screw or slide it into the empty hole. That’s it — your power should now be restored. Be sure to dispose of your blown fuse according to local bylaws.
If your fuses continue to blow, you will likely need to reduce the load or check for shorts on that particular circuit in order to fix the issue. This may involve some rewiring of your home’s electrical system. This requires the skill and expertise of a qualified electrical professional and is not something homeowners should undertake themselves.