Why "short circuit"

  • Dec 14, 2020
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Almost all users with the words "fire" and "electrician" will supplement the phrase with the following: "short circuit". Many are accustomed to awarding KZ with almost magical power and blaming this physical phenomenon for all imaginable and inconceivable sins. But is it? First you need to figure out what a short circuit actually is.

What is short circuit

A short circuit is a connection of two elements of a circuit (most often conductors) with different potentials, or, more simply, voltage.

In everyday matters, this is most often the contact between "zero" and "phase", but the short circuit can be between:

  • In two phases. For example, in three-phase networks, the line voltage of which is 380 V.
  • "Phase" and "ground". Then the ground loop fulfills its main role - it removes the life-threatening potential.
  • Coils in a coil, transformer or motor winding.
  • The winding and housing of any electrical device.
Figure 1: Consequences of a short circuit in a conventional power strip.

A natural consequence of a short circuit is a multiple increase in current strength. Conductors with a cross-section designed for a certain nominal operation are not able to withstand such an amount of current, and therefore burn out.

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The real danger of short circuits

Short circuit is not dangerous because the wire will burn out, at least in an apartment or a private house. In serious production, where an unexpected interruption in work can bring millions of losses - yes, but in home dwellings, this will bring only minor discomfort, to eliminate which it is enough to cause electrician. But a short circuit carries another, much more serious danger.

Short-circuit, according to the Joule-Lenz law, causes a significant release of heat, and under other conditions, it can cause an electric arc. If the protective automatics are selected and installed incorrectly, then in a short period of time the arc can ignite nearby objects: insulation of neighboring conductors, furniture, interior items, personal things. And this is already a source of fire, which will continue to burn even after a power outage in the room.

Figure 2: Ignition of insulation due to short circuit.

How to prevent short circuit?

In order not to worry about the serviceability of the electrical wiring and the integrity of the home, you must do the following:

  • Install a circuit breaker for each separate power and lighting line in an apartment or private house.

Important! Before installing the machine, it is necessary to correctly calculate its value, otherwise the bagger may simply not "see" the short circuit.

  • It is best to mount separate machines on the boiler, hob, washing machine.
  • If the house is old and "plugs" are installed in the panel, they must be replaced with modern circuit breakers.
  • Check the quality of the connections, especially in sockets and junction boxes.
Figure 3: An incorrect machine rating will simply not disconnect a closed line.

And never ignore the first signs of wiring malfunction: sparks, popping, the smell of burnt insulation. Such signals, insignificant at first glance, can soon lead to a serious fire.

P.S. If you are interested in reading in more detail about a short circuit, then I recommend an article on my website - https://www.asutpp.ru/chto-takoe-korotkoe-zamykanie.html