Short circuits in electrical installations can lead to a real state of danger. Damage to electrical devices caused in this way is not only the cost of purchasing new system components - it is also much more serious, such as overheating of wires and even the risk of fire. As a result of an electrical short circuit, there is a rapid flow of energy, so large that it can exceed the permissible current in the circuit, which can lead to dangerous situations. As you can see, this is a very serious topic, which is why we have prepared a short guide in which we will present how to properly protect an electrical installation against a short circuit and how to detect the short circuit location. In addition, we will also present safety regulations and standards and mechanisms for switching off short circuit currents.
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What are the causes of an electrical short circuit?
First, however, let us look at the exact causes of electrical short circuits, a topic that we have already mentioned in the introduction. An electrical short circuit can occur in an electrical installation for various reasons, but it can always lead to irreversible, dangerous consequences. Like a domino effect, it is difficult to stop, which can cause such dangerous events as overheating of wires, damage to equipment or even fire.
The main causes of short circuits include various factors: damage to the insulation of wires (for example due to the ageing of materials), the action of mechanical factors, as well as atmospheric phenomena such as lightning. But not only that, because also incorrect connection of electrical devices, for example incorrect connections of wires in the switchboard.
Overloading the electrical installation, which occurs when the permissible current in the circuit is exceeded, can lead to overheating of the cables and their melting, which in turn contributes to the occurrence of short circuits. Unfortunately, there may also be other causes, such as mechanical damage to the cables (e.g. during renovation work) or simply through neglect in regular inspection of the electrical installation.
What does an electrical short circuit look like?
A short circuit in an electrical installation is a sudden and violent connection of wires with different potentials, most often a phase with neutral or ground. This causes a rapid flow of current with very high intensity. As a result, the temperature at the short circuit point increases very quickly. This can lead to an equally rapid melting of the wire insulation, damage to equipment, and consequently to the emergence of a fire source.
Such a rapid flow of electricity in electrical installations makes itself known in a gentle way, for example by turning off the lights, but it can also be more disturbing, which will be communicated to us by sparking, or even very dynamic, because explosions can occur. In such a situation, fuses in the switchboard can burn out, and circuit breakers can also be activated, which break the circuit to prevent further damage.
Interestingly, an electrical short circuit sometimes does not give any special symptoms, but the fact that it happened can be seen from dark traces or charring on the wires. Similarly, electrical devices can have such residues. In some cases, something else makes itself known - a characteristic smell of burning resulting from overheating and melting of insulating materials.
How to properly protect the installation against electrical short circuit?
As we can see, although the electrical installation works flawlessly on a daily basis, you never know if a threat is not lurking just around the corner, or rather in an inconspicuous box. We have also seen that the causes of electrical short circuits are so diverse that it is difficult to predict them. On the other hand, it is not about prediction, but about appropriately early protection. In accordance with the motto - prevention is better than cure, we can increase our safety by using several key protective measures.
- The basis is definitely an inspection of the electrical installation, which allows for early detection of potential damage to the insulation of wires that can lead to a short circuit. And as we already know, a short circuit is no joke.
- It is also important to use appropriate fuses, differential circuit breakers and overcurrent circuit breakers. Thanks to them, if the permissible current in the circuit is exceeded, the power supply will be automatically disconnected. Surge arresters are also used.
- A well-designed installation must take into account the appropriate load for each circuit, which minimizes the risk of overloading the electrical installation. The key here are especially the installations - grounding and surge protectors. This allows the installation to be protected from atmospheric phenomena, e.g. lightning.
- Equally important, ensuring that electrical devices are properly connected and protected from overload are also necessary steps to control short circuits.
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How to detect a short circuit in the electrical installation?
There is no doubt that a short circuit is the first step towards smaller or bigger problems. However, we should always prevent a short circuit so as not to pose a threat to ourselves and our loved ones. Sometimes, however, a short circuit in the electrical installation becomes a fact, so we need to know how to detect it. After all, we know that it does not always have to be "spectacular".
- To locate them, we must first - and this is very important - disconnect the power supply in the entire circuit. This way we will avoid electric shock.
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Once we have done that, let's use an insulation resistance meter to check which part of the installation is showing low resistance. This indicates the presence of a short circuit. - Next, turn off all devices connected to the suspect circuit and reconnect them one by one to identify if any of them are causing the short circuit.
- It may happen that it occurs in a fixed installation. In such a situation, we can turn on individual fuses or circuit breakers, which will allow us to narrow the search area. Unfortunately, it may also be that the situation is more complicated.
- If so, it is best to use specialist tools such as locators or thermal imaging cameras. They allow you to detect which wires are overheating at the point of short circuit.
- On the other hand, in the event of an electrical short circuit, sometimes the most sensible solution is to call an electrician.
Safety regulations and standards for electrical installations
In the context of safety, it is also worth knowing what the safety regulations and standards for electrical installations are. They are crucial for ensuring protection against short circuits and other hazards. In Poland, this is particularly the case with the PN-HD 60364 standard. It specifies the requirements for the design, assembly and operation of electrical installations.
It also specifies minimum requirements for wire insulation, grounding and protection against electric shock. In this context, regular inspections of the installation are particularly important, because they can detect any irregularities that could lead to dangerous situations. It is also important that the installations are carried out by qualified electricians. There is no joking about electricity!
How does the short circuit current disconnection mechanism work?
We already know a lot, but let's finally find out how the short-circuit current disconnection mechanism works. As we wrote earlier, it is of great importance in the context of securing the electrical installation. It automatically interrupts the electrical circuit when it detects excessive current flow, i.e. when a short circuit occurs.
It consists of a circuit breaker and fuses. The first one - reacts to exceeding the permissible current. It immediately disconnects the contact, interrupting the current and protecting the installation from damage.
Fuses work on a similar principle, except they are disposable. They contain an element that melts under the influence of high temperature by excessive current. In this way, the circuit is broken and the risk is averted.
Now we know what causes short circuits in electrical installations and how to prevent them. This is extremely important knowledge for anyone planning to repair or build an electrical installation. Taking this into account, the offer of the Onninen wholesaler will be useful, where there is everything you need, which we mentioned in the article, but not only, as exemplified by electrical equipment , modular equipment and many others.