Burning electrical wiring is a serious hazard. To extinguish it, you need to use special fire extinguishing agents that guarantee efficiency and safety in the elimination of fire. It is necessary to clearly know which fire extinguisher can and cannot be used when extinguishing energized wiring.

Causes of an electrical fire

Electrical networks in a house or enterprise are a source of danger to humans. Failure to follow safety precautions can result in severe electric shock and fire.

The main causes of fire:

• Electrical fault. The state of all nodes of the engineering network should be taken into account. This is a switchboard to which the main supply cable, branches are connected and protection devices are installed. All devices must be operational. It is necessary to provide backup protection in case of failure of one of the devices. Particular attention should be paid to the quality of the connections of the conductor contacts. For the reliability and safety of the operation of electrical wiring (especially in wet rooms), residual current devices will be needed.
• Unsafe use of electrical appliances. When connecting any devices, it is worth considering the possibilities of the maximum load of the network and the presence of a grounding contact in the outlet. One of the reasons for the ignition of the electrical wiring is a large load on one of the outlets, to which several units are connected at once through splitters and extension cords. In addition, damaged cords and plugs of appliances are a danger.

After turning on the electrical appliance in the network after a while, it is necessary to turn it off and check the plug for overheating. If the plug is hot, then there is damage to the contact fasteners.

• Lighting malfunctions. Lighting fixtures often cause fires in electrical wiring. In rooms with high humidity, it is necessary to provide protection for lamps from splashes and switches from moisture.

The main requirement for any problems with electrical wiring is its complete shutdown. To prevent fire, at the first sign of a short circuit, it is necessary to de-energize the network, and only after that proceed with the repair. Only professional electricians in a special protective suit can work with a live network, eliminating the danger of electric shock.

Short circuit - the cause of the ignition of the wiring

The occurrence of a powerful and destructive current pulse in the network is called a short circuit. It occurs at the moment when the wires of the circuit are connected, but the current does not flow to the electrical appliance. The wiring heats up and a fire starts.

If sparks and open flames appear, turn off the electricity immediately.

If access to the plugs is not possible, the wires must be cut off with any tool that has electrical insulation.

The first signs of an impending short circuit may be interruptions in the operation of lighting and electrical appliances. They should be checked for the integrity of the wires and contacts.

There is current in a burning live wiring, so if it is not possible to turn off the shield or cut the wiring, firefighters must be called.

Extinguishing burning electrical wiring

Extinguishing live electrical wiring with water is prohibited. Water is an ideal current conductor and a person who will water the wiring with water is guaranteed to receive an electric shock. If the network is de-energized, then water, sand or any fire extinguisher at hand can be used.

If it was not possible to de-energize the network, only a fire extinguisher can be used, on the body of which it is noted that it can be used in class E fires. This classification corresponds to fires in electrical installations.

To eliminate fire in electrical installations, some powder and aerosol, carbon dioxide extinguishing agents are applicable. They are designed to extinguish wiring and electrical installations under voltage not exceeding 1000 volts (optimally about 300 volts). If there is a higher voltage, it is necessary to look for ways to de-energize the network.

It is impossible to use foam-air and foam-chemical compositions under voltage.

You can try to extinguish a burning outdoor electrical wiring in winter with snowballs. They will cause a circuit and trigger the protective mechanism of the network.

Rules for extinguishing wiring with fire extinguishers

• Powder-filled fire extinguishers can extinguish burning electrical appliances with voltages up to 1000 volts;
• The carbon dioxide composition is suitable for extinguishing electrical installations with voltages up to 10 kilovolts;
• If the length of the jet of carbon dioxide composition is less than three meters, it is possible to extinguish only equipment under a voltage of 1 kilovolt.

Types of fire extinguishers and their scope

Water and foam formulations

Fire extinguishing devices such as OVP, OV, OHP can be used to extinguish a de-energized network. They can be used to eliminate a visible fire when the cable line that feeds the burning equipment is broken.

Powder formulations

A burning electrical panel with a voltage of up to a thousand volts can be extinguished with a powder fire extinguisher. The powder knocks down the fire and creates a dense layer that blocks the access of oxygen to the place of ignition.

The high efficiency of devices of the "OP" series was noted. They can be used at voltages up to 1 kilowatt.

Carbon dioxide compounds

They are considered the most effective in eliminating the ignition of electrical installations. The OU series knocks down the flame and lowers the temperature of the heated areas. When working with this fire extinguisher, it is worth considering that carbon dioxide emits harmful fumes and it is unacceptable to use it indoors. However, it has a number of undeniable advantages:

• It leaves no traces after complete evaporation. This is important for complex electronics.
• It extinguishes electrical units with voltage up to 10 kilowatts.

If you do not have a fire extinguisher suitable for extinguishing electrical wiring, you can use sand.

Safe distance from which you can extinguish electrical wiring:

• At voltage up to 10 kW - at least 1 meter with a carbon dioxide fire extinguisher;
• At voltage up to 1 kW - at least 1 meter with a powder fire extinguisher;
• At voltage up to 0.4 kW - at least 1 meter with a freon fire extinguisher.

The basics of the fire brigade when extinguishing electrical installations under voltage:

1. When working with foam compositions, grounding of foam generators, barrels and pumps of fire engines is carried out.
2. Maintain safe fire extinguishing distances.
3. Foam fire extinguishers are not used.
4. Extinguishing is carried out in specialized clothing.

conclusions

If it is necessary to eliminate the ignition of electrical wiring at home, it is necessary to use all possibilities to de-energize the network. Typically, the consumer network voltage does not exceed 380 volts. If for some reason it is impossible to turn off the power, a powder or carbon dioxide fire extinguisher should be used.

It must be remembered that if the insulation is damaged, an electric arc can form, it is dangerous for humans.

You can extinguish electrical wiring under voltage with the following fire extinguishing devices:

• Up to 400 Volts - powder, freon and carbon dioxide compounds;
• Up to 1000 Volts - powder and carbon dioxide;
• Up to 10,000 volts - carbon dioxide.

It is forbidden to extinguish energized electrical wiring with foam and water compositions, including sea water.

Electrical fires can be caused by a variety of reasons, including:
- the use of low-quality fuses to protect the network;
- failure of insulation of electrical wiring elements;
- exposure to rodents;
- unprofessional installation of the electrical network.

If the organization of the electrical wiring is carried out in accordance with the PUE, then the network will work without failure for several decades. Operation of faulty devices, network overload, mechanical impact can cause damage to wiring and fires.

Types of wiring damage

The main types of damage are breaks, breaks of cores and short circuits. If the electrical wiring caught fire, the first thing to do is to immediately turn off the current and remove the plugs from the sockets. There are times when access to switches is difficult. Then it is necessary to cut off the wires with any insulated tool.

If concerns about the reliability of the wiring turned out to be fully justified, it is better to completely replace it. When the machines are triggered, you need to inspect the electrical panel, in particular, the terminals. Touching anything is strictly prohibited. The darkening of the machine is a sign that it needs to be replaced. A short circuit can occur due to the simultaneous inclusion of powerful devices. It is necessary to determine which devices were turned on at the time the automatic protection was triggered.

The most common cause of a wiring fire is a faulty power cord. To prevent serious consequences, check the sockets with the machine turned off. When a source of ignition is detected, the electricity is first turned off and the socket is dismantled with a screwdriver. Next, carefully disconnect the damaged wires with pliers.

Most often, sunbathing occurs on the cord of irons. In this case, you must immediately disconnect the device from the mains, cover the flame with a rag and extinguish the fire. There is no need to panic if an open cable suddenly caught fire. The electricity supply is promptly turned off and the place of sunbathing is covered with earth (many houses have flower pots). When eliminating fires in electrical wiring, it should be remembered that soldering or connecting various wires is possible only in junction boxes. That is, if the wiring breaks under the plaster, you need to replace the damaged area, and not just connect the ends of the wire.

The use of modern automatic fuses allows you to save property, and often people's lives.

A fire broke out in the village of Lenkovshchina, Molodechno district. The residential building burned out completely from the inside, the ceiling and roof were destroyed throughout the area. A man died - a disabled person born in 1994. The cause of the tragedy was faulty wiring. As it turned out, the mother, leaving for work, left the TV on for her son.

It was in the room where the TV was on that the fire started...

For nine months of this year, 903 fires occurred due to violation of the rules for the construction and operation of electrical networks and electrical equipment. 29 people died in the fire.

The problem of violating the rules for the installation and operation of electrical wiring becomes especially relevant with the onset of cold weather, when the load on the power grid increases, - said Yury Lapitsky, chief specialist of the supervision and prevention department of the Ministry of Emergency Situations.

New owners, old wiring

In the 1980s, household electrical appliances in the average apartment could be counted on the fingers of one hand. But then a young family moves into an old apartment or house. Modern man can no longer imagine his life without a washing machine, microwave, computer. Electrical equipment creates an increased load on electrical networks designed more than 30 years ago and designed only for a refrigerator and TV ...

Even in new, newly built apartments, the wiring is designed for the average number of electrical appliances, and not for three TVs, two refrigerators and several laptops connected to the network at the same time, rescuers say. And here safety should become the concern of the residents themselves.

When entering a newly built house or apartment, it is advisable to invite a specialist who would advise what protection devices should be installed in the switchboard, - says Yuri Lapitsky. - The same is important to do when purchasing an apartment or a house built decades ago. Only a specialist can assess the required level of protection for the power grid - for example, an electrician from the housing and electrical service, another specialized organization. As a rule, safety devices are installed for every two or three electrical appliances in operation. In the event of a dangerous power surge, the fuses will cut off the electricity supply to the corresponding section.

As a rule, in a modern house, the kitchen is the most difficult area in terms of load - in addition to the refrigerator, hood, backlight, microwave oven, electric kettle, etc., housewives also like to install a TV and a food processor there. And it is in such areas that an additional protection device is needed, which will turn off the supply of electricity in the event of a short circuit.

Of course, you need to invest some money. But this is an investment in your own safety. Protection devices are inexpensive and are sold in almost every hardware store, in hypermarkets and building supermarkets. They are delivered to rural settlements by raipo auto shops.

Three million for a "bug"

The risk group is poor categories of citizens: single and lonely pensioners, the disabled, large families, - says the interlocutor. - The positive trend in the reduction of fires was largely facilitated by the implementation of relevant state programs, which include, among other things, bringing electrical wiring to a fireproof state. Wiring has already been replaced as part of these programs this year in 10,000 households.

For violation of fire safety norms and rules, administrative liability is provided - a fine of up to 30 basic units.

Any adult is able to assess when it is time to change the wiring: if the wiring cannot withstand the load, the fuse constantly works, as they say, “knocks out the plugs”. If the wiring is dilapidated, the braid crumbles, there are cracks on the insulation. And of course, it's time to take action if bare wires show through.

The employees of the Ministry of Emergency Situations oblige the owners of the house or apartment to change the wiring when they find a “bug” in the fuse - an uncalibrated fusible link. "Craftsmen" wind the wire around a faulty fuse and insert it into the meter. There is light and all electrical appliances are working, but if there is a short circuit, the protection device will no longer turn off the power supply to the dangerous section of the electrical wiring, and in the best case, the refrigerator or TV will fail, and in the worst case, the house will instantly flare up along the perimeter.

Of course, the most problematic category of such “craftsmen” are those who lead an asocial lifestyle. But quite prosperous citizens also sin with such tricks. Someone is too lazy or has no time to go to the store for new fuses, someone has a maximum load on the network and constantly “knocks out traffic jams” ... People hope for a chance, and they can pay for carelessness with the loss of property, their lives and the lives of loved ones. Isn't the price of carelessness too high?

Faulty electrical wiring poses a strong danger to people and structures, because in most cases it is a source of fire. In the event of a fire from electrical wiring, the first thing they try to find out is who is to blame for this and at whose expense it is necessary to carry out restoration work. Next, we will consider the main causes of wiring fires and ways to protect against this dangerous situation.

Causes of ignition of electrical wiring

In case of neglect of safety measures in the room, a fire may occur. Also, electric shock can lead to serious consequences. We will consider the most popular causes of ignition of the wiring below.

Technical difficulites. It is important to monitor the condition of all network wiring, as well as their connections. This includes the main and switchboard, because it is in such places that the main cable lines are supplied, and various protective devices are installed. All devices must be in working order. Back-up protection should be installed in the switchboards in advance, which can be used in case of some dangerous situation (for example, protection against short circuit). Basically, ignition of electrical wiring is possible due to poor contact, therefore, special attention should be paid to the junctions of the electrical wiring. For safety and reliability during operation, it must be installed in an apartment, in production or in workshops, especially where there is high humidity.

Smoothly moving from one reason to another, it should be noted that often the ignition of the wiring in the apartment occurs due to the fact that incorrectly selected circuit breakers. The fact is that the purpose of the machine in the shield is to instantly work in case of a short circuit or overload in the network. So, with regard to overload, when choosing a circuit breaker, you need to pay attention to the fact that the nominal value of the machine corresponds to the cross section of the wiring to protect which it is installed. Otherwise, when overloaded, the cable in the wall will start to melt and may catch fire, and the machine will not work, or it will work when it happens, which may be too late and still cause a fire in the house or apartment.

Incorrect or unsafe operation. Each device has a load limit. The cause of the fire may be the connection of various splitters or extension cords to the same outlet. Damaged plugs or appliance cords are a great danger. If a short time after turning on some electrical appliance in the network, the plug or splitter heats up, this means that there is a problem in the contact connections.

Lighting group fault. Lighting devices eventually become the cause of the outbreak. For example, it is necessary to protect an incandescent lamp from splashes, and a switch from moisture.

Technical failures include connection of aluminum wire with copper. Even if everything is connected correctly and the neutral wires are connected with a special bar, a fire in the wiring can occur. For such connections, a bar made of brass material is not suitable, because over time it oxidizes and aluminum with brass heats up, which consequently leads to a fire. If such a compound was inside a combustible plastic shield, then the consequences would be even worse, because instead of preventing combustion, it begins to melt and support the hearth. It is possible to connect aluminum with copper, if it is impossible to perform electrical wiring in any other way. However, the connection must be made either through special or using special sleeves.

Another reason is poor quality and old sockets. After all, the plug of the electrical appliance itself must fit tightly into the outlet. If the plug gets hot or sparks, change the socket immediately. It is better to pay a little more, but buy a quality outlet. Although they may look the same, in cheap models, the plastic heats up and lights up, and the contacts do not have compression springs. About that, we told in a separate article.

The next reason is old aluminum wiring. In old multi-storey buildings, switchboards are located in the stairwell. Often they are in a very neglected state, so there is a particular risk of fire. Also, in most old houses, the electrical wiring has never changed, which means that it has already outlived its usefulness, the insulation becomes unusable, and, accordingly, does not protect against a short circuit in the wall. To this we can add that now much more electrical appliances are used than before, therefore the load increases on the old wires, which can be aluminum and withstand small loads.

Today there is a problem low-quality electrical goods. These products do not withstand the load declared by the manufacturer. It is often necessary to troubleshoot a house or apartment that has only recently been rewired. After about a couple of years, the cable insulation cracks and begins to crumble, and this inevitably leads to a fire.

Visually, some of the causes of a wiring fire are discussed in the video:

Fire protection measures

Various protective measures should be taken to keep the wiring in good condition, such as running it under plaster and not under flammable building materials. As for the shields, it is better to choose them from metal or non-combustible plastic - this will serve as protection against the spread of fire. We have covered this in detail in a separate article.

It is also important to do at least once a year: look at all wire connections in sockets, switches, junction boxes and in the electrical panel itself. Timely detection of poor contact and melted wires is one of the effective ways to protect against fire.

If the wiring is old, be sure to replace it with a new one at the next repair. Cracked insulation, old sockets designed for a lower current load, plugs in the shield. All this can lead to a fire at any moment. If it is not yet possible to spend money on, be sure to install machines and RCDs in the shield. They will save you from a fire at the right time. It is also desirable to install a fire RCD for 100 or 300 mA at the input in wooden houses, as an additional measure of protection.

The fire RCD is described in detail in the video:

In addition to all this, it is important to know and in no case repeat, which we wrote about separately. For example, a poorly made twist can cause a short circuit and further ignition of the electrical wiring. Therefore, twists do not need to be done at all.

And of course, if the apartment smells of burnt wiring, and you yourself are not able to find and fix the problem, be sure to call an electrician, after turning off the machines in the shield.

How and how to extinguish a burning electrical wiring

To extinguish burning wiring, it is necessary to use special effective fire extinguishing agents. It is necessary to understand well what to do, how to extinguish, what should be the procedure and which fire extinguisher is applicable when extinguishing wiring.

Among the most urgent problems in the field of fire safety is the fire protection of residential buildings and public buildings. When investigating the causes of fires, as a rule, one of the main versions is a malfunction of electrical wiring and other electrical products.

All-Russian statistics claim that 25-30% of fires occur due to malfunctions and violations of the rules for the operation of electrical wiring and electrical appliances.So, in the period from 2009-2013, due to violation of the rules for the construction and operation of electrical equipment, 3011 fires occurred on the territory of the Khanty-Mansiysk Autonomous Okrug-Yugra, which is 25% of the total number of fires that occurred during this period (in total -12272). In the fires that arose for the indicated reasons, 81 people died - 15% of the total number of deaths during this period (532), and 224 people were injured - 19% of the total number of victims (1196).Out of 3011 fires due to violation of the rules for installation, operation of electrical equipment, electrical networks, household appliances and protection devices, 1783 fires occurred over 5 years - 60% of cases.

Why do these fires happen?

For each electrical load, determined by the number and quality of devices connected to the power grid, a certain section of the electrical wire is selected accordingly. If the cross section of the electrical wire does not correspond to the load value, then the wire will heat up and the greater this discrepancy, the more the electrical wiring heats up.Most of our housing stock is houses 20-30 years old, or even older. The electrical wiring of these houses was designed for a certain, limited consumption of electricity - up to 1500 watts.The number of electricity consumers during the design and construction of these houses was limited - TV, refrigerator, radio, a few light bulbs. Now we have televisions - almost in every room, in addition, air conditioners, microwave ovens, washing machines, stereos and other benefits of scientific and technological progress, which are now in abundance. The load on the power grid has now increased significantly, and the electrical wiring has remained old, and sometimes dilapidated. Connecting the next purchase to the power grid, we hardly think: “Will it withstand the next increase in load, will the inclusion of the next electrical appliance lead to overheating and ignition of the electrical wiring?”.

In addition, when the load is more than permissible, the automatic shutdown is triggered or the fuse in the plug fuse blows. Then, in place of the calibrated fuse insert of the cork fuse, the “craftsmen” use all kinds of “bugs”, or even just such a device that is unacceptable in electrical engineering like a nail or something like that. Sometimes they change the circuit breaker to a more powerful one, the operation current of which does not correspond to the state of the wiring. In this case, the electrical wiring operates in an overloaded mode - it heats up, its insulation melts, and the two conductors touch each other, that is, a short circuit occurs. This is accompanied by a sharp increase in current strength, while the wires instantly heat up to a high temperature, intense sparking occurs, and if combustible materials and structures (curtains, wooden furniture, etc.) are nearby, they instantly ignite.

There are also other causes of ignition of electrical wiring insulation:

1. Overheating of electrical wiring, which can be:

Local, arising in a certain place in the electrical circuit due to a large contact resistance, that is, poor electrical contact. For example, at the junction of electrical wires "twisted" or when the contact surfaces are oxidized;

On an extended section of the electrical circuit, due to overloading of this section. For example, when using one outlet to connect several sufficiently powerful consumers of electricity.

2. Sparking at the junction of electrical circuits, at the terminals of electrical appliances, due to loose electrical contact. In particular, due to the loose contact of the plugs in the sockets of the socket outlet, significant heating and melting of the socket occurs.

3. Current leakage:

From uninsulated sections of the circuit through pollution and conductive dust in junction boxes, switchboards, etc.;

From isolated areas through damaged insulation.
Today, on the territory of the Khanty-Mansiysk Autonomous Okrug-Yugra, 8878 multi-apartment residential buildings with low fire resistance are registered. In the period from 2009 to 2013, 1044 fires occurred at these facilities - 8.5% of the total number of fires in this period (12272) with the death of 98 people. Fires in such houses are accompanied by the rapid spread of fire and the destruction of the building completely.

Unfortunately, we have to state that today the level of fire prevention of operated electrical installations of buildings is very low. The main methods of prevention are visual inspections of networks, protection devices, including checking their calibration, and other elements of the electrical circuit. Therefore, reducing the fire hazard of electrical networks is one of the main tasks in the prevention of fires.

The occurrence of emergency modes in electrical installations is not a spontaneous event, but "originates" and intensifies gradually from day to day. However, even at the very initial stage, it is already possible to diagnose such modes, because in the places of their "origination" anomalous heating immediately begins to occur. First, these are units of degrees, then tens, and, reaching heating over 100-200 degrees Celsius, an irreversible process begins that will inevitably lead to ignition of the wire insulation, followed by the occurrence and development of fires.

It is also important that modern protection devices and devices for protective shutdown of electrical circuits are not able to “recognize” most emergency modes in time (such as loose contact, insulation damage, incomplete short circuit, etc.), and sometimes do not de-energize the electrical chains even when combustion has already begun.

Therefore, in our opinion, one of the most promising methods of fire prevention of electrical installations is the thermal method of non-destructive testing (thermal imaging diagnostics), which allows you to detect defects in contact connections, areas of cable overload by exceeding the temperature, to assess the thermal state of electrical equipment during its operation without removing voltage . Thus, it becomes possible to detect many defects at an early stage of their development and thereby prevent possible fire hazard situations.

As you can see in photo No. 3, at first glance (image on the left), the contact group looks quite ordinary and does not cause any concern. However, thermal imaging diagnostics shows that one of the cores (in red insulation) at the point of contact has abnormal heating, which is absent on the other two cores in the group. Such heating indicates the presence of a loose contact connection, which, during further operation, will heat up to higher temperatures and ultimately lead to a fire. With the timely diagnosis of such a malfunction, a simple tightening of the connections will be sufficient and the heating of the core will be eliminated.

The relevance and effectiveness of introducing thermal imaging surveys into practice are confirmed by the results of the testing laboratory of the municipal institution "Ramenskaya Rescue and Crisis Response Service" (MU RamSpas). In the period from November 2008 to February 2010, a selective thermal imaging survey of electrical of which 137 are children's institutions, 17 are cultural institutions and 44 are other, including residential facilities.The surveys were repeated at 52 facilities.

A total of 455 defects were identified at 134 (that is, 68% of the number of surveyed!) objects, of which 101 are emergency, fire hazardous, requiring immediate elimination. No defects were found on 64 objects. The main causes of accidents were poor-quality bolted contact connections and uneven load distribution by phases. In some electrical panels, overheating reached values ​​​​of more than 300 ° C!

As can be seen from the foregoing, surveys of electrical networks of objects using a thermal imager are highly effective in identifying and targeted elimination of fire hazardous elements in electrical equipment. The indisputable advantages of a thermal imaging survey are: the objectivity and accuracy of the data obtained, no need to turn off the electrical equipment. In addition, the method is distinguished by the simplicity of documenting defects and the ability to identify defects at an early stage of development, which makes it possible to use thermal imaging surveys to assess the state of electrical equipment in terms of its fire safety in practice.