The main cause of fires associated with violation of the rules for the design and operation of electrical equipment and appliance is a short circuit. It occurs due to insulation failure in electrical wires and cables, caused by overvoltage, deterioration of the insulation, and mechanical damage. The danger of a short circuit is an increase in current strength by hundreds of thousands of amperes, which causes a large amount of heat to be released in the conductors in a very short period of time, which in turn leads to a sharp rise in temperature and ignition of the insulation.
What is a “short circuit”?
A short circuit is a connection of two points of an electrical circuit with different potentials, which is not provided for by the normal operation of the circuit and leads to a critical increase in the current strength at the junction.
Thus, a short circuit leads to the formation of destructive currents exceeding the permissible values. Which contributes to the failure of devices and damage to the wiring. In order to understand what can provoke this process, you need to understand in detail the processes that occur during a short circuit.
Causes of occurrence for appliance short circuit
In real conditions, a short circuit occurs in the following situations:
- Damage to the insulation of conductors. This can happen due to the deterioration of the insulation, as well as the mechanical impact on it. The cable cores are terminated directly or through the equipment case.
- Incorrect connection of electrical appliances to the network. This case is characterized by the assumption of a mistake by the master or the owner of the apartment, which is why a short circuit occurs.
- Ingress of water into an electrical appliance. Of course, water should not be allowed to enter electrical appliances, because it is a good conductor of electricity and closes the contacts.
Causes of a short circuit and how to prevent it
There can be any number of reasons, let’s dwell on those that, according to emergency statistics, happen most often.
- Deterioration of electrical equipment of energy systems or household electrical network. It happens when the insulation of the wires loses its dielectric properties. Then an unintended electrical connection occurs in such a section in the circuit.
- Exceeding the permissible load on the supply circuit. It causes heating of current-carrying elements, which leads to damage to the insulation.
- A lightning strike in overhead lines. In this case, a short circuit causes an overvoltage in the mains. lightning does not have to hit directly into the power line, if the discharge was close, it causes ionization of the air, which increases its electrical conductivity. As a result, an electric arc is formed between the power lines.
- Physical impact on the wires, which causes mechanical damage to the insulation, as well as the hit of metal objects on conductive elements. This violation can be caused by negligence in housekeeping.
- Connecting faulty equipment to the network. For example, it can be caused by a decrease in internal resistance.
- The human factor. A fairly broad definition, which includes a huge number of cases of careless or incorrect human action: errors in the installation of electrical wiring, unsuccessful repair of electrical equipment, improper work of substation personnel.
A short circuit occurs as a result of damage to conductors or electrical devices, their incorrect connection, or an overload of the network. The consequences in this situation can be very diverse: from a simple breakdown of the device to a fire or shock to people. As a preventive measure, a short circuit can be prevented by using the correct fuses, as well as cables with a suitable cross-section. Be careful when carrying out repair work. Do not allow mechanical damage to the wiring, carefully study the necessary diagrams of energy systems in your home. If you approach everything wisely, there will be no problems with a short circuit and then you will not need to fix it.