How to choose fuses for your car

How to choose the right car fuses

Despite its rather small size a fuse is very important for the proper operation of the car and each of its individual systems. The reliability and condition of the fuse directly affects the integrity and safety of the entire vehicle. Every motorist should know what fuses are and where they are located. This will allow, if necessary, to replace them with your own hands, without asking for help from specialists. Fuses are needed to protect the onboard power system from sudden voltage surges that occur in the event of a short circuit. Thanks to the fusible element, it melts when in danger, thus breaking the contact between the equipment and the power going to it. By breaking the mains, only the fuse burns out, but the component, system or unit that was protected by it remains intact. There is nothing wrong with the failure of these elements. Replacement is easy to do with your own hands, and they themselves are quite cheap. Their cost is dozens or sometimes hundreds of times less than the price of the equipment that protects the fuse.

How to choose fuses for your car


To begin with, let’s understand the existing types of car fuses. They can be classified according to the materials used and the design itself. Since everyone now knows what these very fuses are needed in the car, it is worth examining their varieties. Now to the question of what are the fuses used in the car. Let’s start with the materials of manufacture. Here the key role is played by what exactly the fusible component is made of. That’s why elements are divided into:

  • aluminum;
  • tin;
  • lead;
  • Alloy (combination of lead and tin).

The most important characteristic of the product is the speed or response time. That is, the time interval in which the fusible element has time to melt and disconnect the circuit. The faster the insert can melt, the less likely it is that the equipment being protected will be damaged. To achieve the desired result, these inserts are made of special alloys and metals with low melting points. They are capable of rapidly changing from solid to liquid. To increase the tripping speed, some fuses are additionally equipped with a spring-loading system. Structurally, fuses used for cars can be divided into finger-type and flag-type fuses.

Finger products are widespread on the classic models of cars of the domestic automaker in the form of AvtoVAZ. These are rods, on which a special fusible link is put on. At the same time, finger fuse constructions for cars are divided into plastic and ceramic fuses. Given some of the features of the fuse blocks, which are equipped with Zhiguli cars, the most preferred option is considered a ceramic element. It has greater resistance to high temperature, are considered more reliable and do not contribute to false triggering if the fuse begins to heat.

Fuse block

But on modern cars, the finger-type designs have been abandoned. Now the main mass of fuses is represented by flag safety elements. They are superior to their finger-type counterparts in terms of ease of use and also superior in terms of reliability. Flag fuses are also often referred to as blade fuses because they are designed with a pair of legs required for contact when installed in their socket inside the fuse block. The name flag fuses can be explained by the rectangular or square top where the fusible element or jumper itself is located. The heads on the flags make different colors, which directly depends on the rating. Visually really resembles a flag, hence the name. Flag elements in the fuse box are appreciated for the good and strong contact in the seating socket. But to remove the device requires the use of a special fixture.

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The automakers foresee this point, and place plastic pliers on the cover of the fuse box on its inner side. If necessary, such a tool is easy to find at any automotive supply store. If you operate in extreme conditions, or simply have no time to look for and buy pliers, you can grasp the flag with pliers. But here it is extremely important to be careful not to accidentally provoke a short circuit of the leads. It is still better to take a specialized device.

The concept of the rating

To learn all the existing types of fuses used for cars, it is not enough to know about the design and material. Here of great importance are the ratings, that is, the size of the amount of current that the element is able to pass through itself. When choosing fuses for the car, which are needed as a replacement for burned ones, it is always and necessarily necessary to look at this characteristic. The fact of the matter is that a different amount of electrical equipment in the vehicle is connected to different electric lines. Each power consumer has its own specific power. It is quite logical and natural that the circuit for powering the headlights needs a much higher capacity than in the case of the circuit for powering the interior lights. This means that the headlight fuse must have a higher capacity than the safety element for the interior lights. The rating, which refers to the amperage that can flow through the fuse, is measured in Amps. The rating depends a lot on what type of fuse is used. Flag fuses are much more varied in this component, and are presented with different ratings. And the already quite obsolete finger designs have only 2 types of ratings. These are 16 and 8 amps.

Color dependence on the rating

Dependence of color on the rating

Experienced motorists can simply tell by the color of the flag fuse exactly what the rating of a particular fuse is. It is not unreasonable to study all types of ratings and types of their color designation. The varieties of protective elements presented are standardized, and therefore apply to all modern cars. That is, automobile fuses of different makes and models still have approximately the same color designation depending on the value of the rating. They may differ in shades. We suggest you also look at this characteristic and find out at which color what the current rating of the protective component will be.

  • 1 Amp fuses are mostly colored in black;
  • If the color is gray, the current flowing through the element will be 2 A;
  • violet is the color for devices with a rating of 3 A;
  • 5 A is determined by the brown-yellow color;
  • pure brown color corresponds to 7.5 A;
  • if you see a red flag, that’s 10 amps;
  • for 15 amps they use blue paint;
  • all yellow fuses are 20 amps;
  • 25 amp fuses are white;
  • green items mean that the rating here is 30 amps;
  • orange flags provide for 40 amps;
  • blue identifies 60A fuses;
  • light brown elements mean 70 amps;
  • 80 A can be recognized by the light yellow color;
  • all lilac-colored devices go for 100A.
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It is important to keep in mind that the shades of devices may vary slightly. That is why it is better to look in the instruction manual of your particular car, and also carefully study the information on the fuse block cover and digital marks on the fuses themselves. The nominal value is calculated on the basis of what load is laid on the electric circuit, when all the consumers powered through a fuse are switched on, plus a small margin of safety. All these parameters are calculated at the production stage. Information about the location and purpose of each individual fuse is described in detail in the operating manual and in the repair instructions. Plus, the cover of the fuse block itself also contains useful and necessary information for the motorist. Before replacing a burned out element, you should check what its rating is, buy the same fuse, and install it in place of the old protection element.

Why it is important not to mix up the fuses

Every one of you already knows and understands very well that all fuses have a certain rating, and it is adapted to specific sockets. Each socket leads to one or another of the vehicle’s electrical lines. If the motorist mistakenly or due to a lack of proper knowledge misplaces fuses that are differently rated, quite serious problems can arise. When the rating turns out to be excessively small, the fuse element will break down very quickly under relatively small loads. The electrical-dependent equipment itself, to which this fuse is connected, can operate normally and under standard loads. But the protective element itself is adapted to a lower amperage. And if it encounters a value that exceeds its melting threshold, the fusible component is destroyed, the circuit is broken and the equipment shuts down. It doesn’t have to be a short circuit here. The fuse will burn out without it.

There is another situation, when fuses designed for a large load are installed in place of a fusible flag with a small rating. Then nothing can happen to the protective component even with a significant increase in current, up to a short circuit. The fusible component does not perceive the load as high, but for the protected equipment the values have exceeded the permissible standard. A short circuit occurs and the circuit does not open. Since the protective element did not work, the car wiring starts to burn, and all the equipment can fail. As you can clearly see, it is highly undesirable to confuse fuses that have different ratings. It is necessary to use only those fusible elements, which were provided by the automaker for each specific seat in the fuse block. The same factor forbids and strongly recommends not to use improvised means, such as a wire, a coin and other tools for replacement of fuses. Usually this is done in situations when you do not have special pliers and you need to replace a burned element urgently. But you risk a lot by using improvised tools. Especially it concerns any metal objects.

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Here it is important to understand that the fuse is unlikely to just blow, if it is installed in the correct socket and has the appropriate rating. You can’t use a wire or coin to open a circuit when electrical equipment has been shorted. You will only cause more problems. Your attempts to use a metal object can cause a fire and a fire. That’s why special pliers only. If you lose the factory tool, which is usually located on the inside of the fuse box cover, buy new pliers from an auto store.

How to choose a fuse?

Selection Recommendations

To ensure that the fuse did not fail at the most crucial moment, before installing it, you need to make sure that the protective characteristics of the element are effective. Old burned flags are not repairable. They are affordable consumables, which are replaced as needed. But before you install a new element, you need to understand the reasons for the failure of its predecessor. When there are problems in the car, a simple replacement won’t do anything. A new fuse will burn out just as quickly as the previous one. Changing it several times a week is definitely not an option. If the problem with the car is solved, then you can safely buy and install the protective component in the fuse box in the appropriate socket rated. When choosing, it is recommended to adhere to a few simple tips.

  1. Manufacturer. Trust well-established companies that make truly quality products. Since fuses are cheap and in high demand, many try to bring their own product to market. And not always it has a good level of quality. Even such elements are better to take from proven manufacturers.
  2. Place of purchase. Beautiful packaging and a well-known name on it does not yet indicate that in front of you a good fuse. Often motorists are faced with fakes and cheap copies of the original protective devices. To avoid such situations, it is advisable to go to certified sellers and stores with a good reputation.
  3. Thickness. It happens that fuses with different ratings have exactly the same thickness of fusible jumpers in their design. This is a clear sign of a counterfeit or low-quality product. The higher the rating, the thicker the jumper, because it is designed to melt under higher loads. If you notice the same thickness on nominally different fuses, feel free to throw out the entire package. Such items are not suitable for use.
  4. Short-circuit test. Rarely are fuses sold and purchased by the piece. Usually it is a whole package, which serves the car owner long and faithfully, stored in the garage or in the car, so that there is always a spare fuse if necessary. It is possible to sacrifice one of them, thus making sure of the quality of the whole batch. To do this, short-circuit it manually. Only it is not necessary to sacrifice your car for this purpose. It is enough to connect a pair of wires to the outputs of the protective element through the terminals type mom, and connect the opposite ends to the outputs on the car battery. Be sure to disconnect the battery from the power grid of the vehicle itself. After such a connection, a good and functioning fuse will burn out. If the fusible element remains intact, but the body itself begins to melt, you have bad fuses. Their use is strongly discouraged.
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The most effective way to ensure long and trouble-free operation for fuses is a series of measures aimed at preventing a possible short circuit in the onboard electrical network. Try not to overload the car with unnecessary equipment, realistically estimate the capabilities of the generator and the battery. Also always watch the condition of electrically dependent units, systems and mechanisms. It is impossible to be fully protected from short circuits and overloading of electrical system of the vehicle. For this purpose special fuses are foreseen, which actually sacrifice themselves, so that the equipment does not suffer. After all, its cost is much higher compared to the price of one simple fuse.

More expensive is better? Consumer test of car fuses

Responsible motorists try to choose quality parts for their cars whenever possible, but with fuses sometimes this pattern fails. Often fuses are bought on a “what was” basis. Can they be trusted and is it possible to economize on them?

To try to at least approximately answer these questions, we purchased six sets of Mini format fuses from those that could be bought “here and now”. The cheapest set cost a modest 1.59 rubles, the most expensive 7.50. The difference is impressive, and the three manufacturers did not skimp on the special tongs.

From left to right: 1.59 rubles, 2.29 rubles, 2.49 rubles, 4 rubles, 5.19 rubles, 7.50 rubles.

We are going to test the fuses in the consumer format with the help of a laboratory power supply and a stopwatch. We will be testing 5 and 7.5 amp fuses since the current capacity of our unit is limited to 10 amps. Allow two minutes for each fuse.

Which one gave up first?

To begin with the test with the rated current. It would seem, what surprises could there be? But it wasn’t: 5 amp representative from Airline made a click and was gone after 5 seconds. No way!

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Since the Airline dropped out of testing ahead of time, we will continue to work with five copies. We will increase the current gradually: each cycle will add 25% to the nominal.

The starting point is 6.25 A. Of all the test pieces, we can distinguish two. The Tesla fuse burned out at the 43rd second. There is a first result!

The second “marked” was the Bosch fuse, which visibly melted. The other fuses not only didn’t burn, but even heated up barely noticeably.

Increasing the current to 7.5 amps. Cheap Autostandart and Pilot got warmer, Alca fuse got hotter, and Bosch fuse turned the circuit off in few seconds after applying current.

We continue the test already with a current of 8.75 A. At this point, Autostandart, Pilot and Alca were left “alive”. Alca burned out after 9 seconds, but the first two do not seem to care.

And what about the maximum?

Finally, we increase the current to the maximum possible for the LBP 10 amps and connect each of the fuses for another two minutes. Both Autostandart and Pilot got hotter, but plastic didn’t change in the allotted time, fuses also refused to blow. There could have been a video here, but believe me, it is quite a boring sight. Not the best specimens?

Now it was the turn of the 7.5 amp fuses. All fuses passed the test this time, including the Airline fuse, which was doubtful because of the first test failure.

Since it is no longer possible to increase gradually the current due to the limitations of the power supply unit, we decide to set the maximum 10A at once.

Autostandart and Pilot again “distinguished themselves”: in two minutes they didn’t burn out, but the power unit became an absolute pity. The plastic case of the Pilot managed to get noticeably hot, melted and lost some shape.

The Airline, on the contrary, confidently “clicked” in 11 seconds after power-up. What was the fuse then at 5 amps?

The Tesla, like the previous time, was the first to show the result one would expect: at 10 amps the fuse lasted 8 seconds.

The Alca, on the contrary, remained unscathed. Rejoiced too early with the test result of the 5 amp representative?

At last, Bosch. The fuse from the most expensive set “gave up” at 28 seconds. It also did it more beautifully than the others, though such aesthetics will hardly be appreciated by someone when a fuse burns out in a car.

Our verdict

The results of all tests are summarized in the table. The three cheapest sets of fuses are definitely questionable. Tesla, Alca and Bosch showed themselves noticeably better, but the cost of Bosch raises questions: almost twice as cheap Tesla seems to win all, and therefore we give them our vote.

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