Why does a fuse blows

If the task of identifying the cause of a blown fuse is daunting, read on to discover nine reasons that a fuse may blow. Before we get to the root of the problem, it's important to know what a blown fuse looks like. The most obvious sign of a blown fuse is charring on the fuse itself, but another sign is that you will likely lose power in some or all of your house.

This is the circuit breaker doing its job, containing the fault and preventing it from affecting other circuits. Now that you know what a blown fuse looks like let's take a look at nine possible blown fuse causes. The most common cause of a blown fuse is when something draws too much power from the circuit.

This is most often caused by either too many lights or from using too many plug-in appliances at once. The biggest culprit for this kind of issue is a multiple outlet adapter plugged into a socket. Circuit breakers are there to prevent further electrical damage in the case of a blown fuse. But if the breaker continuously trips, this could indicate a problem. A short circuit, in simple terms, is when a current is diverted on a path it is not supposed to go down.

A number of things can cause this, from damaged wiring and accessories to moisture and insects! A ground fault is a type of short circuit where the current is redirected to the earth or ground hence the name.

If there are any problems with actual circuit connections, loose screws, or eroded wiring, this can cause an arc fault. These faults can be dangerous — they are the most common cause of electrical fires in the home. This issue can be one that is difficult to spot due to the wiring being behind the walls. In the event of a blown fuse, the condition of the wiring may still be something you may not think to check.

Check out this list of signs that there may be wiring problems in your home. If your electrical outlets are old, there is an increased chance of them having faulty wiring or loose connections. This can cause appliance fuses to blow if incorrect currents are reaching the plugs. Although fuses all look very similar, there are, in fact, many different types and sizes. Having the wrong fuse can be dangerous and cause significant damage in your home — if you suspect there may be an incorrectly sized fuse, stay away from the fuse board and call a professional.

If your home has issues with damp, or if any storm damage has been inflicted on your home, there is a chance that moisture has made its way into the wiring. Make sure the reason is not an undetected fault! If it happens frequently without any apparent reason and an electrician can't find anything, maybe you should replace the fuses with appropriately rated circuit breakers.

Then all you have to do is flip a switch when the lights go out again. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Why does fuse blow up sometimes? Ask Question.

Asked 9 years, 9 months ago. Active 5 years, 6 months ago. Viewed k times. Ron Ron 3 3 gold badges 7 7 silver badges 10 10 bronze badges. Last time, It blew up when I turned on the microwave oven. Add a comment. Active Oldest Votes. The amount of current which is guaranteed to cause the fuse to blow within a certain period of time. The amount of current and voltage which the fuse is guaranteed to safely prevent from flowing once it blows in some cases, the fuse's resistance once it blows will be sufficient to limit current to a safe limit provided its voltage rating is not exceeded; that is not always true, however, in the absence of external resistance.

In all cases the fuse is to weak. Thats what I guess in your case. Sorry for my bad english. Frank Frank 51 2 2 bronze badges. The reason why a fuse blows can be really manifold. Here are just a few, off the top of the hat: The fuse is designed for too small a current and does blow as it actually should at the given current.

You have a device in your household that introduces extra spikes that make the fuse give up. Check for large consumers, e. If the fuses blow when these are turned on, then they are very likely to be the culprits. Faulty wiring. This can be especially the case if your wiring is very old. In case it's older than 30 years, it might make sense to rip everything out of the walls and have the cables installed again.

Simply a faulty household appliance. Happened to me before. One of my lamps had the insulation gone off on a tiny section of the cable, right where it entered the lamp, under the gasket, so I couldn't see it. It produced a spectacular short which blew the fuse on that outlet and the fuse for the whole appartment Bad quality fuses Manufacturers designed them to stop the circuits from overheating. They have fail-safe mechanisms that prevent excess power from going through them.

When a mechanism in an appliance malfunction, it may create more amperage than its fuses will allow. When too much amperage travels through the electrical system, the wires in the fuses will melt. You would call them blown fuses. Furthermore, electrical surpluses that occur one after another may weaken filaments and cause fuses to blow. Circuits that short also cause fuse failure. A short can happen when there is a hot wire to the ground.

It may open a fuse and cause it to fail. Of course, fuses burn out over time. To find out if it is the cause of the blow, replace it. If there is still no power, your device probably malfunctioned. As mentioned above, some fuses have low melting points and are more fragile than others. A sudden surge of electric current may cause them to come apart. Getting to the root of the problem is a complicated process.

You may have to hazard a guess and find out if any appliance you're using has malfunctioned. Examine cords and connections to unveil the problem. Unfortunately, many of these problems are not so easily solved.