Automotive fuses: the main types of circuit protection, how to make a choice according to the parameters of the strips

Modern cars use various electronic systems that are responsible for safety and simplify transport management. The trouble-free operation of numerous electrical systems and all kinds of automatic control units is ensured by special automotive fuses that prevent short circuits, excluding the fire of the wiring and the transport itself funds.

Relay assignment

The main purpose of fuses is to protect the electrical wiring of the vehicle from short circuits and overloads. In cars in the electrical network, depending on the type of car, the voltage can be 12-24 volts. In the event of short circuits, the voltage in the network can increase, which leads to a fire in the wiring or the failure of expensive control units.

Fuses in the event of short circuits completely de-energize an individual circuit or the entire electrical wiring of the car, which protects it from heating and melting. Without such protective devices, even with minimal overloads or short circuits, the wires in the car straighten out, which can lead to a car fire.

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The principle of such protection is extremely simple. In the event of a short circuit and overload, they open the circuit by melting the fusible element, which is located inside the protective relay. After melting the protection, the circuit is opened, which prevents its heating and other critical damage. You just need to choose the right fuse, which in its parameters corresponds to the characteristics of the voltage in the car's network.

Device and classification of fuses

Today there are several types of fuses for cars, which differ in their design, principle of operation and purpose. There are also highly specialized modifications of protective relays that are designed for special equipment and heavy vehicles.

Cylindrical modifications

Cylindrical automotive protective relays were used at the end of the last century and were installed on cars from domestic manufacturers.

Initially, these fuses were made of the same color, but later, depending on the rated current, they began to be marked with different colors.

The disadvantage of this type of car fuses is the possibility of getting an electric shock and burns to your fingers when installing and removing the protective cylindrical inserts. Relays are not standardized, therefore, when choosing a car, car owners had to study all the technical characteristics and only then choose a fuse for their car.

Knife protective strips

Knife strips have a number of advantages over cylindrical modifications. First of all, this is complete protection against electric shock and burns when replacing them. They have a special insulated part made of durable colored plastic.

By the shape of the case and the color of the plastic, you can determine the rating and type of fuse. These protective relays were offered with different rated currents: from 1 Ampere to 100 Amperes for trucks and special equipment.

The body of the protective strips was made with a transparent insert, which made it easy to identify a blown fuse and replace it. Total three standard sizes of knife car fuses were offered:

• Mini - with a landing size of 16 mm.
• Standard - 19 mm.
• Maxi - 34 mm.

Due to its affordable cost and ease of use, car blade fuses have been popular in the market. They are still successfully installed on cars from domestic and foreign manufacturers. Their advantages include affordable cost, complete safety of use, the ability to easily select a protective relay for a certain rated current of the electrical circuit in the car.

Thermal varieties

On modern vehicles, where the maximum possible protection of the vehicle electrical circuit is required, use special thermal fuses, which include both thermal and electromagnetic protection.

The design of such a relay resembles a circuit breaker used in a household electrical network. In case of short-circuits and overloads, thermal and electromagnetic protection is triggered, which allows you to simultaneously prevent the failure of various electrical units and prevent the wiring from igniting.

The benefits of thermal varieties include:

• Maximum possible protection of electrical units and wiring circuits.
• Complete safety of use.
• The relay is reusable, which allows it to be reused.

Thermal fuses for cars are expensive, but they are reusable due to their special design. The insulated plastic case of the relay contains data on its rated power, which greatly simplifies the selection.

Threshold indicators

One of the characteristics of automotive fuses is their operation threshold, that is, the value voltage in the network, at which there is a melting of the conductive vein and the opening of the wiring circuit in car.

Melting of such a protective conductor occurs due to exposure to high temperatures at an increased voltage in the circuit. Accordingly, in the manufacture of fuses, veins of different fusibility indicators are used. This allows the relay to be made for circuits with specific voltage ratings.

Reasons for failure

There are several common reasons why automotive fuses blow out and need to be replaced. These reasons include the following:

• Bad fixing of the relay in the socket of the block.
• Wrong choice of the bar according to its rated current.
• The presence of faults in the wiring of the car.
• Mechanical damage to the plastic case, excessive heat and vibration loads.

Most often, fuses fail due to their mediocre workmanship. In order to save money, many car owners buy such relays, choosing the cheapest models that have the appropriate workmanship.

As a result, during the operation of the car under a significant load, for example, when the car owner simultaneously turns on the wipers and tries to start the engine, there may be slight voltage fluctuations in the network, which leads to melting of the case and complete failure protection.

Self replacement

If the headlight, any electrical unit, wipers and other electrical devices stop working, the car owner needs to check the fuse box and replace if necessary burned out relays. Such a replacement is not difficult and takes 15-20 seconds on the strength.

It is only necessary to correctly select the rated power of the replaced fuses, which will ensure subsequent absence of any problems in the operation of electrical equipment and guarantees protection of the electrical circuit against overvoltage and closures.

If the fuse blows out several times in a row, then you should look for existing faults in the electrical circuit. It is not recommended to operate such a car.

The car owner will need to worry in advance about the presence in the glove compartment of several spare relays with different ratings. They should be purchased from trusted manufacturers, since poor quality fuses are difficult to enter into landing sockets in the installation block and do not provide adequate protection to the power network, without de-energizing the circuit even with critical loads.

Features of work

When installing a new fuse instead of a blown one, it is necessary to use a relay with the same current rating. If you use protective strips with a rated current higher than the permissible, then such protection in case of abnormal situations and network congestion simply will not work without providing adequate security car.

If the value of the rated current is underestimated, the protective relay will burn out even with minimal voltage fluctuations in the network. Such small fluctuations can be noted at the time of starting the engine, when an increased load is placed on the battery and starter.

You should not try to repair a blown fuse by replacing the protective vein in it or installing a so-called bug. The cost of quality protective relays is minimal, while refurbished and remanufactured strips do not provide adequate protection for the vehicle. Savings of several hundred rubles may result in the car owner in the future in the need to replace the failed control units. Such repairs will cost tens and even hundreds of thousands of rubles.

If the fuse in the car constantly blows, this may indicate wiring problems and frequent short circuits in the network. Do not try to troubleshoot existing problems yourself. Ideally, the car should be de-energized by disconnecting the battery, and taken by a tow truck to a service where a specialist using a special voltmeter will be able to determine the nature of the problem and repair the broken one block.

Automotive fuses are special devices, the main purpose of which is to protect the electrical circuit and various automatic control units against overvoltage and short circuits. Protective relays are installed in a special block, they can be performed with different rated voltage, providing high-quality protection of the car. The car owner only needs to choose the right bar, taking into account its type, purpose and rated voltage in the network.