We know that electricity was one of the most revolutionary phenomena of all time. Today electricity is indispensable, and every day a new possibility arises through this phenomenon that has already become essential to human life. Any professional in the field know how important safety is when it comes to electricity, when carrying out any installation or maintenance, in addition to ensuring the safe and proper functioning of the installation or machine he is doing maintenance, it is very important to ensure your own safety and the safety of the people who use or frequent the facilities for which he is responsible. And to make mandatory some measures to protect the safety of people and facilities that the standards techniques. ABNT (Brazilian Association of Technical Standards) specifies, among other measures, that electrical installations are safe and work in the best possible way.
One of these measures to protect the installation and the people who frequent the installation is grounding. Electrical grounding is one of the safest forms of interference in electrical current to protect and ensure the proper functioning of the electrical installation, in addition to meeting the requirements of the standards for electrical installations. Before we talk properly about grounding, we need to understand some points.
The electrical distribution concessionaire basically supplies two power wires: neutral and phase. These threads can be identified on their surface or by colors. The neutral has the potential equal to zero and the phase cable is the cable through which the transmitted electrical voltage passes. However, this connection is not perfect, because there are variations in electrical voltage.
Probably the voltage level of your home is 110 V or 127 V. The potential difference between the cables generates the electric current, for example, the neutral cable with 0 V and the phase cable with 127 V, the potential difference ( voltage) between them is 127 V, at a point where there is this potential difference it is possible to circulate an electric current. However, the example cited is not always true, as there may be “dirt”, caused by the leakage of energy in electrical and electronic devices.
This leak is on the surface of electrical or electronic equipment, it can occur due to defects, failures or even on certain individual characteristics of the devices. When leaning against this surface, we are subject to an electric shock of varying intensity. The more electronic components the equipment has, the greater the intensity and frequency of this energy leak, as in computers.
The shock happens because there is a potential difference between the person touching this equipment and the equipment. Just like the potential difference in the cables, but in this case, the person suffers an electric shock. But if, instead of a person, an electrical appliance with a potential difference leaning against an appliance with a power leak, can cause damage to this appliance, however small, the most sensitive components can be damaged.
What is electrical grounding
According to ABNT, electrical grounding means placing facilities and equipment at the same potential, so that the potential difference between the earth and the equipment is as small as possible. The ground is the connector with a potential difference equal to zero, the difference between it and the neutral is that it does not change its value by means of “dirt”, on the contrary, by means of the earth this dirt are eliminated, which does not allow energy leaks to remain on the surface of electrical appliances. This dirt are eliminated to earth, hence the name.
Objectives and importance of grounding
As already mentioned, grounding is in compliance with safety standards dictated by ABNT, in addition to ensuring the proper functioning of the installation and safety regarding phenomena that may compromise the proper functioning of the equipment. We can point out some of the main objectives:
- Protection of the physical integrity of people:
As already explained, this leakage current that is on the surface of the equipment can be transmitted to the body of the person who touches this device. The intensity of this shock may not be as severe, but many of the consequences of undergoing electric shock are not linked to the intensity of the shock, but to external factors. So it is best to avoid this contact with energy.
- Facilitate the operation of safety devices:
Imagine a device with a power leak that is not in a grounding system, so the way in which this energy leak will be eliminated from the equipment will be when a person leans against this equipment. But if this equipment is connected to a grounding system, this excess energy will be carried by the ground cable, and if this excess is harmful to the operation of the installation, the safety devices ( circuit breakers , fuses, etc.) will come into action, interrupting the operation, for example.
- Discharge electrostatic charges from the equipment housing:
The permanence of these electrostatic charges on the equipment’s surface puts its performance at risk, as sensitive components can be harmed. Electrostatic charges are formed at all times by friction, for example.