Electrical grounding, types and uses.

Grounding has the function of protecting electrical equipment, users, and also ensuring the proper functioning of the circuit. There are different types of grounding, some of which have variations. Here you will learn what these types of grounding are, when they are used and their applications. Come on guys!

All grounding systems must follow the NBR – 5410 standard, failure to comply with the items contained in the standard can put users and equipment at risk, in addition to malfunctioning of the circuit.

Symbology:

First letter – food situation in relation to land.
T- A point directly buried;
I- Isolation of all living parts in relation to earth or ground through an impedance.
Second letter: the situation of the installation’s masses in relation to land.
T- Masses directly grounded, regardless of the eventual grounding of a feeding point;
N- Masses connected directly to the grounded supply point which in alternating current the normally grounded point is the neutral point.

Other letters: Neutral conductor and protective conductor arrangement.
S- Neutral and protection function provided by different conductors.
C- Neutral and protection function combined in a single conductor.

Grounding schemes

TN scheme:

It has a feed point directly grounded, the masses are connected to that
point through protective conductors. This diagram has three variants according to the neutral and protective conductor arrangement, which are:

TN-S scheme:

The neutral conductor and the protective conductor are distinct, the neutral being grounded at the entrance and taken to the load, in parallel another PE conductor is used as ground and is connected to the equipment frame.

Grounding scheme TN-S.

TN-C scheme:

The neutral and protection functions are combined in a single conductor throughout the installation, so this scheme, even being standardized, is not indicated in certain installations, since the earth and neutral are made up of the same conductor.

TN-C earthing scheme.

TN-CS scheme

The function of the neutral and protective conductor is combined into a single conductor and part of the installation.

Grounding scheme TN CS.

TT layout:

This diagram has a feed point directly grounded, with the installation masses connected to a grounding electrode electrically different from the grounding electrode of the source, that is, the equipment is grounded with a proper rod, different from the one used for the neutral.

TT earthing scheme.

In the case of the fault current, the path of the mass phase current includes the earth, which limits the current value due to the high value of the earth resistance, it is important to remember that this current is not sufficient for the isolation of the protection devices, but it is a dangerous chain for users.

IT scheme:

This scheme is similar to the TT, but the source is grounded through an impedance with a high value. This limits the current so as not to allow the first fault to shut down the system. The installation’s masses are grounded with the following possibilities:

Grounded grounds on the same grounding electrode as the supply, if any

IT grounding scheme.

Masses grounded in their own grounding electrode, either because there is no grounding electrode for the supply, another possibility is because the grounding electrode for the masses is independent of the supply grounding electrode.

Many residential installations in Brazil do not have an adequate grounding system, even though it is mandatory according to the standards of electrical installations, it is important that you know the importance of having a grounding scheme in the installations.
Therefore, hire a professional in the area, so that you can choose and execute the appropriate scheme, as it is necessary to have a project built and based on collected data and tabulated parameters, in addition to taking into account soil resistivity