Sooner or later you have to deal with such a phenomenon as a short circuit (SC). A suddenly switched off light in the apartment, a switched off computer, a silent radio, or a stuttering children's electric toy - all this may be the result of a short circuit in the current conductors. Electrical engineers comment on this situation with the short word “short”.
When it's short
Why are there short circuits in wires and contacts?
The main factor of a short circuit is a breakdown of the insulation of current conductors. Violation of the integrity of the insulating sheath of wires, breakdown of contact resistance in an electrical or electronic circuit - all this causes a short circuit.
The main causes of short circuits include:
- high voltage surge;
- insulation wear;
- mechanical damage;
- penetration of foreign objects;
- lightning strike.
High voltage surge
Voltage fluctuations in the centralized power grid are often observed in remote areas of rural areas; such cases also occur in urban environments.
During a voltage surge that far exceeds the permissible standard, the risk of breakdown of the insulation of wires or electrical circuits increases sharply. A situation is created in which the wiring shorts and a short-term arcing may occur.
Insulation wear
The old dielectric sheath of wires dries out over time and can self-destruct. Failure to replace old wires over decades often leads to short circuits.
Mechanical damage
External mechanical impact on the electrical network leads to damage to the insulating layer of conductors. An example of this would be drilling into walls with hidden wiring. A drill caught between the wires causes a short circuit.
Penetration of foreign objects
Dust and small debris that get inside the housing through the cracks of the ventilation grille of an electrical or electronic device most often provoke the occurrence of a short circuit between the elements of the device. Short circuits are sometimes caused by insects and small rodents.
Lightning strike
Natural electrical discharge “attracts” the electromagnetic field of various electrical equipment. A powerful magnetic circuit can become the target of lightning.
Consequences of a short circuit
During a short circuit, the voltage drops and the current in the electrical circuit increases. This process is very dangerous:
- A source of ignition appears in places where the conductors of the device elements come into contact, which often becomes the cause of fires.
- The resulting electromagnetic waves affect communication and communication lines.
- A drop in voltage causes malfunctions in the operation of household appliances and electrical equipment, including serious breakdowns.
- A whole chain of accidents may occur, which leads to a complete disconnection of electricity consumers from the system until the cause of the electrical short circuit is eliminated.
This is interesting. People have learned to use short circuits for their own purposes. For example, the operation of short circuiters is based on the principle of this phenomenon. These are special devices for deliberately closing a circuit for the purpose of protective shutdown of high-voltage lines in case of emergency situations.
What is a short-circuited turn
Hidden wiring is convenient and economical!
Many electrical appliances and devices use coils - these are chokes, transformers, magnetic starters, contactors. Electric motors have windings on the armature and stator. Short-circuited turns may occur in these parts. There are several reasons for the appearance of this type of short circuit:
- poor-quality winding of wires (overlapping turns, excessive tension);
- mechanical damage to insulation;
- moisture penetration;
- insulation burnout from a power surge.
Types of wiring closures
Hidden wiring in a wooden house: PUE
Electrical communications can be one, two, or three phase. All electric motors have windings consisting of many turns of wires. In all these types of power transmission there are short circuits:
- A short circuit in single-phase wiring occurs when the phase wire is shorted directly to the ground or to any grounded element. The cause may be improper grounding or a violation of the surface layer of the conductor.
- A two-phase circuit occurs when two current-carrying branches of an electrical circuit are in full contact. A short circuit also occurs when two phases are simultaneously shorted to ground.
- A three-phase or symmetrical short circuit is the connection of three wires with different phases to each other. This may be caused by mechanical damage to the conductors, overheating, insulation breakdown, or the result of overlapping wires.
- The closure of the windings of coil parts is called interturn. This type of short circuit is typical for electric motors, transformers and various devices.
- One of the dangerous types of short circuit is when the power wire breaks inside the power unit and its subsequent short circuit to the metal case. If the current is not turned off at this time, people may be unexpectedly shocked by high voltage.
Types of closures
Signs of a short circuit
The first signs that may indicate a short circuit in the apartment and which should not be ignored.
Melted insulation
Various melting of conductors, melting of metal parts, burns are a clear sign of a short circuit, especially if the shape of the melting is spherical, teardrop-shaped, oval, or in the form of recesses with uneven beads.
Socket sparks
Bright flashes and sparking when connecting devices to the network may indicate a short circuit in the apartment, which makes it impossible to use the equipment in the future.
The smell of burning
The appearance of a smell of burning wiring in the house means that some area is very hot, therefore, poor contact occurs there. Action should be taken immediately.
Causes and elimination of short circuits in cables and connections
Short circuit occurs for the following reasons:
- physical wear and tear of insulation;
- damage to insulation by rodents;
- significant overheating of cable insulation;
- direct connection of phase and neutral wires.
Physical wear and tear of insulation
Proper wiring – trouble-free electrics in the house
Insulating sheaths for wires are made mainly from polyvinyl chloride. Vinyl material can maintain its performance qualities for decades. But an aggressive environment can significantly shorten the service life of the protective layer of wires. All types of insulating tapes are subject to the same factor.
Elimination of short circuits due to physical wear and tear of cables and wires involves constant monitoring of the condition of the conductors and timely replacement with new electrical products.
Important! When the sound disappears in the right or left channel of headphones or speakers, you should check the condition of the power supply wires. Poor soldering and low-quality insulation can cause a short circuit, and sound-reproducing devices fail. This is often found in cheap Chinese products, where thin, wear-out wiring is used.
Damage to insulation by rodents
Mice and rats are often the culprits of short circuits. Cables installed in basements and underground areas are often at risk of damage from rodents. By gnawing through the protective sheath of power conductors, small animals provoke short circuits between exposed wires and to the ground.
Such negative phenomena of laying underground communications can be eliminated by using armoring of the surface layer of cable insulation. Armored cables have increased protection from external physical influence, including rodents. In this case, it is necessary to rehabilitate the habitats of small pests.
Note! Rodents often appear in garages. Feeding on food supplies in the basements of the boxes, mice and rats do not disdain the insulation of the car wiring. They can damage the wires coming from the battery, starter or generator. As a result, the power wires short out, which can drain the battery and cause a fire in the car when driving.
Significant overheating of cable insulation
As a result of high heating, the insulation is destroyed, which is even worse - it can catch fire. Overheating occurs as a result of a sharp increase in the number of amperes of current. This is usually caused by voltage surges in centralized power outlets.
The owner of the home decides how to protect against sudden increases in voltage and current. Sometimes it is better to contact specialists so that they can offer the best option to prevent overheating of cables and wires. An effective means of preventing a negative factor is the installation of automatic safety blocks.
The electrical network of a house or apartment is divided into separate branches, which are powered from a specific machine. The purpose of each device is marked.
In order to avoid overheating of the PC motherboard, the computer is connected to an outlet through a voltage stabilizer. Stabilizers are also connected to other electrical and electronic devices. In some cases, a single stabilizer is installed at the input of the power supply network.
Direct connection of phase and neutral wires
As a result of direct contact between the phase and neutral wires, a short circuit occurs instantly. The most dangerous thing is that an electric arc can occur, which can lead to a fire and cause significant destruction of the surrounding area.
Consequence of a short circuit in the electrical panel
When hidden wiring shorts
A short circuit in hidden wiring can be caused by the following reasons:
- mechanical penetration into wire cores;
- water leakage;
- voltage surges.
Mechanical penetration into wire cores
During repair work (sheathing walls with plasterboard, installing fasteners, changing the plaster layer, etc.), there is a risk of mechanical damage to the wire insulation. This is fraught with a short circuit of the exposed wires of the hidden wiring. Drills and hammer drills are often to blame for this. A drill or chisel, having pierced the wiring, shorts the wire strands, causing a short circuit.
Water leakage
Saturation of walls with moisture, leaks from above or from the outside of cracked vertical fences sometimes causes a short circuit in hidden wiring.
Power surges
A short circuit from overheating of old insulation occurs due to a sharp change in current characteristics. Heating melts the protective sheath of the wires, causing a short circuit.
Short circuit from voltage surge
External signs of a short circuit
The location of a short circuit can be determined by various criteria:
- Visual inspection.
- Using a megohmmeter or multimeter.
- Elimination method.
- Folk method by sound and smell.
Visual inspection
You can repair the wiring or contact connection by visually identifying the location of the short circuit. They find the section of the wiring where the short circuit occurred due to burnt insulation and leaks of molten metal cores. The same signs are found on the contact surfaces of electrical connections.
Using a megohmmeter or multimeter
These devices are effective detectors of breaks and short circuits in electrical circuits. A short circuit manifests itself as a lack of resistance on the phase path to grounding.
A megohmmeter is used to test high-voltage power lines. The multimeter is set to resistance measurement mode by setting the device's turn signal to the desired position. Using a multimeter is one of the best ways to find a short circuit in hidden wiring.
Additional Information. To test the windings of devices, it is easy to make an indicator of short-circuited turns with your own hands. A schematic diagram of such a device can be found at https://radionet.com.ru/shem/shem77.html.
Elimination method
To find a short circuit point in the circuit of a radio-electronic device or hidden wiring of a room, the exclusion method is used. The current-carrying branches of the circuit and individual wiring branches are turned off one by one. If a short circuit does not occur anywhere, then you need to continue the search until the short circuit manifests itself.
PCB short circuit
Folk method by sound and smell
The method for finding short circuits is quite simple. An unpleasant strong smell of burnt insulation emanates from the source of the short circuit. If the short circuit is accompanied by sparking, it produces a crackling sound and loud clicks.
How to find a short circuit in wiring
As a rule, the search for a short circuit occurs after the plugs or circuit breaker have been knocked out.
There are several options here:
- visual inspection;
- use of special devices;
- exception;
- by sound;
- by smell.
External inspection during short circuit
If you find that the insulation is damaged or the contact of two exposed wires is damaged, you can assume that the cause has been found.
Typically, such damage can be found in junction boxes, switches or sockets where wires are connected.
If you notice a burnt shell, this is a malfunction.
How to find short circuits using instruments
It is better to use a megohmmeter or multi-meter for this. They will quickly check the resistance in the circuit.
Connect one wire of the device to the phase and the other to ground (to zero).
If the device shows zero, the wiring is normal. Anything above zero indicates contact contact.
It is worth considering that the multimeter has a small resistance, so it is not always possible to determine a short circuit with its help.
How to find a closure using the elimination method
Everything is simple here, but the method is effective in case of fault of the electrical appliance.
When your breaker is knocked out, turn off all electrical power.
Then turn on the machine and start connecting each of the devices.
How to find a short circuit by sound and smell
When the contacts close, you can hear a crackling sound. The main thing is to have good hearing.
By the smell of burning plastic and light smoke, you can easily find a broken wiring in the house.
How to fix a short circuit
Your actions should be as follows:
- remove the damaged area and reconnect the contacts, being well insulated;
- As for sockets and switches, it is easier to replace them with new ones than to restore the contacts;
- It is recommended to replace the old wiring completely (although the pleasure is not cheap, life is more expensive);
- Repair your household appliances or get rid of them altogether.
If you have no experience working with electricity, it is better to call an experienced electrician who knows exactly what to do.
Remedies and prevention
First, they get rid of the reasons that caused the short circuit. The burnt wiring is replaced with new wires. Radio components and coils that have become unusable are replaced with similar new components.
Prevention of short circuits involves installing safety automatics, voltage stabilizers, replacing old equipment and worn wiring.
Safety circuit breaker block
Timely measures taken to prevent the occurrence of short circuits will preserve expensive equipment, electronic devices, and household appliances. We must remember that a short circuit can destroy not only property, but also people’s lives.
Short circuit and its elimination
What often affects the electrical wiring in an apartment, which sometimes requires partial replacement of the electrical wiring? Yes, a short circuit may be to blame. Every electrician will tell you that usually a call to an electrician, even an urgent call to an electrician, is required in the event of a short circuit. Many have experienced the shorting of electrical wires, followed by a bang with a flash, first-hand. We will tell you about what a short circuit in the electrical wiring in an apartment or house is, the possible causes of its occurrence and consequences. We will describe some ways to eliminate the consequences of a short circuit and prevent electrical wiring. Let us remind you that the services of an electrician come in handy not only when you need to carry out electrical installations or carry out new wiring.
