The grounding system is fundamental and mandatory for all installations, whether residential, building or industrial. Grounding systems not only offer safety, but also have the characteristic of being functional. There are still professionals who have doubts on how to make a correct ground, so we will teach you how to make a residential ground, in addition to explaining what electrical ground is, what types of grounding and much more, come on guys!
What is the electrical grounding?
The electrical ground is one of the ways we have to safely interfere in electricity, it is important to point out that he not only has the aim of protecting us, through protection devices, but also to ensure proper functioning of the electrical installation.
When we refer to electrical grounding, it means that we are placing the installation and electrical and electronic equipment on the same potential, so that the potential difference between the earth and the equipment is zero.
What is the electrical grounding for?
The grounding system has basically three functions, one of which is to protect against rain with strong atmospheric discharges, since the grounding will protect the user of the equipment that is in use, so that an alternative path is created for the passage of the electric current towards the earth.
Another way that electrical grounding can act is on the housings of any machine or electrical equipment, as it is common in these cases to be accumulating electrostatic charges in the masses, and there is a need to be diverted drained towards the earth. It is important to highlight that in these cases, with a good execution of the grounding system, it guarantees the safety of the physical integrity of people, because it avoids electric shocks by indirect contact with the metallic parts that are exposed conducting electricity.
Last but not least, a good grounding system contributes to the proper functioning of protection devices, such as fuses, circuit breakers, residual differential switch (IDR) and surge protection devices (DPS), which will start working at the right times , minimizing the chances of more serious accidents.
According to the NBR 5410 standard, there are basically three types of grounding scheme, the IT scheme, the TT scheme and the TN scheme, which has its variations, being TN-S, TN-C and TN-CS, so know each one of them is essential to make a good choice and according to the specifications of the standard. Below is a video that will help you to clarify your doubts about each type of grounding and where they are most used.
To make a ground, it is not enough to make a hole in the ground and insert the copper rod in any way and make the connection of any wire and take it to the circuit distribution board (QDC), on the contrary! It is necessary to follow the standards, using appropriate materials and tools, to ensure an excellent electrical ground, starting with the parts for assembly as some below:
- Copper rod: it is the main piece that has the purpose of draining electrical charges to the ground, as it offers a very low impedance (resistance).
- Inspection box: guarantees the passage, diversion and access to the electrical networks and its structure provides greater durability to the installation
- Connectors: these are necessary elements to make the connections between the conductor of the mesh and the grounding rods, equipment and ungrounded metal parts.
- Conductors of the grounding mesh: these are the cables used to connect the ungrounded metal parts, such as the metallic structures, equipment or the descent conductors, connected to the grounding rod. It is important to remember that the conductors have specific colors and gauges according to NBR 5410. The grounding conductor must be of the same section as the phase cable, as long as it is up to 16 mm².
In order to know if the grounding was done correctly and if it will be efficient, use a thermometer, the NBR 5410 standard does not say exactly what the impedance (resistance) value of the grounding should be, but it indicates that this value must be very low, the closest to zero as possible.v