The case of short circuit rises sharply. Short circuit, causes, consequences, protection

Welcome everyone to my blog! You know, what's happened short circuit , causes, consequences and what kind of protection is there? I'm sure you know. I won’t tell you anything new, so you don’t have to read any further))) Just kidding. Let's talk about the phenomenon of a short circuit.

Those who even occasionally read my blog know that I recently had an accident. I dedicated the post “” to this story. Read it.

The article gained great popularity on the Internet. A living example after all. Based on it, one “Electroshaman” wrote interesting article about "EXPLOSION bags".

What happened, what were the reasons? I read assumptions in the comments.

Answer to hide in a word - closure. Of course, I’m not 100% sure, everything happened quickly, but that’s what’s written in the accident report. I quote briefly:

When pulling, a short circuit occurred between the contact group and the body of the package switch through the tip of the screwdriver that AZ was holding in his right hand.

Soon I’ll tell you more about this act, what’s there, how, subscribe to the news so as not to miss it. So:

What is a short circuit?

This is a connection of two points of an electrical circuit with different potentials that is not intended by design.

There are:

• Single-phase,
• Two-phase,
• Three-phase,
• Interturns,
• On a metal body.

Consequences of a short circuit:

They are accompanied by a large release of heat, an electromagnetic field, melting of live parts, fire, which leads to fires, power surges, disruptions in the functionality of the electrical circuit, system accidents in power grids, etc.

I think each of you knows a case of fire that occurred due to a short circuit in the electrical wiring of a house or apartment. A common occurrence.

An electric arc can also occur from a short circuit, as in my case. By the way, as promised, a photo of that same electrical panel after the accident:

It's a little dark, but you can see it.

Causes of short circuit:

Can be caused by overload, various problems, for example: a fault in the switch or plug socket, weak connection in the lighting box, mechanical damage to the cable insulation, malfunction household appliances without system protection.

Malfunctions and damage can occur both due to careless handling and physical wear of system elements. For example, if the switch has a broken spring contact plate or a crack in the cover, it must be replaced.

The reasons can be listed for a long time, if anyone has unique cases, share your story in the comments, it’s interesting.

Probably every person has seen a short circuit in our lives. This is when two conductors, for example, phase wire and the neutral or phase A wire and the phase B wire, without any resistance, are directly connected. The current strength increases hundreds of times, resulting in a spark or electric arc, depending on the voltage and load in the network. Happening. A very dangerous thing that causes great harm to your electrical equipment.

What causes a short circuit

A short circuit is most often associated with phenomena such as load and overload electric current. Load is the passage of current through a conductor. The greater the load, the more the conductor heats up and the faster it becomes unusable (heating of the conductor also depends on its resistance, in other words, what material the conductor is made of). In this regard, you can look at. As long as the temperature remains within normal limits, the insulation copes with the load, a short circuit will not occur.

If the wire constantly overheats, the insulation will deteriorate faster and a short circuit may occur. Rubber shrinks and bursts, paper and yarn become charred, and plastic melts.

Overload is already a current that causes very strong heating of the conductor. Accordingly, the stronger the overload, the faster the insulation will fail and a short circuit will occur. If the insulation is lost, a short circuit occurs and the circuit is not disconnected, then an insulation fire may occur.

What happens and common causes of short circuit

A short circuit causes nearby ones to burn out or turn off. Very often, a short circuit occurs when an electrical appliance is connected to the network. I can advise you to look for the cause of the short circuit in a malfunction of the device itself.

In my experience, I can think of several reasons for a short circuit. Firstly, there is mechanical damage to the wire; secondly, careless handling of exposed wires; third, short circuit metal objects, pins , internal parts cartridge; fourthly, rubbing of the insulation in places where the wires are bent; fifthly, bending at right angles, etc.

How to avoid short circuit

Avoid short circuit when . To do this, we restore the route, that is, we virtually connect junction boxes, sockets, switches and lamps. The resulting lines will indicate where the wire runs. In these places, I do not advise you to drill or hammer anything in order to avoid a short circuit. Also, it is necessary to correctly install the protection to avoid short circuits.

Well, that’s basically all I wanted to tell you today about such pests as short circuits. I will be glad to see you again on my website. Lots of useful stuff related to electrical installation work and electrical engineering, can be found at. Write comments, all the best.

Every day, whether at home or at work, we close electrical circuit, and nothing explosive happens. Closing the circuit with plug electrical appliance, electricity is converted into:

• - V mechanical energy— engines of pumps, vacuum cleaners and various electrical devices.
• - V thermal energy — hot air hairdryer, boiling water electric kettle, thermal radiation from an electric convector.

This is a good closure, let’s call it conventionally as opposed to a short, “long” closure of the electrical circuit.

A short circuit has a negative result, that is, the energy positions itself in the form of sparks, bangs, often ignition of wiring and easily flammable materials - a fire.

What is a short circuit?

Example: A locomotive must deliver cargo, say from a city Nizhny Novgorod to a metropolis like Moscow. The journey of the train must be long. A locomotive, pulling 50 wagons of coal behind it, picks up speed. But suddenly, in the city of Vladimir, the dispatcher makes a fatal mistake, switching the arrow to the track where another train is located - an accident cannot be avoided.

A train that has gained high speed cannot be stopped quickly. A clear example may seem primitive, but I would like to show the underlying principle - this is strength, power, used for other purposes, bringing destruction. The route of the locomotive with many cars turned out to be short, incomplete, and did not reach the goal.

It is the POWER of current that produces destruction; during a short circuit, the current increases by 20 times, the amount of heat increases by about 400 times.

Here is another clear explanation of what a short circuit is.

It is known that faulty electrical wiring leads to a short circuit, which most often causes a fire. This is often mentioned in fire reports. What is a short circuit, and why is it dangerous?

In normal operation, the current in the wiring between phase and neutral wires flows through the load, which limits this current to a level that is safe for wiring. When the insulation is destroyed, current flows, bypassing the load, immediately between the wires. Such contact is called short because it occurs in addition to the electrical appliance.

Let's remember Ohm's law: I = U/R, which is usually pronounced like this: “The current in a circuit is directly proportional to the voltage, and inversely proportional to the RESISTANCE.” It is RESISTANCE that is worth paying attention to here.

The resistance of electrical wiring is, as a rule, small, so it can be neglected and considered equal to zero. According to the laws of mathematics, division by zero is impossible, and the result will tend to infinity. In the event of a short circuit, the current in the circuit will tend to this same infinity.

Of course, this is not entirely true, the wires have some kind of finite resistance, so the current, of course, will not reach infinity, but it will be strong enough to produce a destructive effect, a fairly powerful explosion. A voltaic arc occurs, the temperature of which reaches 5000 degrees Celsius.

Causes of short circuit

• Errors of personnel servicing electrical networks.
• Due to wear and tear of (outdated) electrical wiring.
• Incorrect wiring installation.
• Poor contact in wiring connections and electrical appliances
• Due to electrical circuit overload.
• May occur due to mechanical damage wires
• Shortcomings can be caused by rodents.

How to prevent a short circuit?

To prevent short circuit it is necessary.

• Properly install and operate electrical installations.
• Select electrical wiring in accordance with the current value.
• Carry out regularly scheduled inspections and measurements of insulation resistance;
• Choose the right automatic protection devices that are designed to disconnect the damaged area.
• Before working with the wiring, it must be de-energized.

Benefit of short circuit

Arc welding, which is used in production, was born on the basis of a short circuit. Point of contact between the rod and metal surface heats up to melting temperature, metal structure merges into a single whole. For example, modern car bodies are fastened precisely through a short circuit - arc welding.