Grounding system, which one to use?

There are still many doubts about residential grounding, for example, what is a grounding system? What is the application of the grounding system? What is the ground wire used for in electrical installations? Among other doubts. We explain what electrical grounding is, what electrical grounding is for, and what types of grounding, come on guys!

What is the electrical grounding?

Basically, electrical grounding is one of the ways to interfere in electricity safely, in order to protect and ensure the proper functioning of the electrical installation and mainly to protect ourselves through protection devices.

Electrical grounding means placing installations and equipment at the same potential so that the potential difference between the earth and the equipment is zero. The grounding is done so that, when operating electrical machines and equipment and when performing maintenance, the operator or professional in the area does not submit to the electrical discharges of this equipment, either by leakage current, which is going to the ground or by electrostatic discharge.

Grounding schemes:

There are several types of grounding according to the NBR-5410 standard, such as:

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 different, 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.

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.

Explanation of electrical grounding.

TN-CS scheme

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

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.

In the case of the fault current, the path of the mass phase current includes the earth, which limits the value of the current due to the high value of the resistance offered by the earth, it is important to remember that this current is not sufficient for the isolation of protection devices, but it’s 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:

What is the grounding for?

Grounding systems have several functions, one of which is to make the equipment and devices of the circuit perform better and be fundamental in the functioning of the protection systems and devices, in addition to guaranteeing the physical integrity of people.

The objectives for the earth cable to existing are:

Make sure that electrical charges that arise abnormally in electrical equipment are conducted directly to earth.

Avoid further damage to the installation due to electrical surges, such as lightning strikes.

Contribute so that the protection devices present in the circuit work perfectly, being activated instantly after the failure.

To be an excellent ground, it is necessary that its main characteristic is a very low resistance, close to zero, having the ability to safely conduct any fault current.

This low resistance facilitates the operation of the protection devices and drives any undesirable currents that cause noise to the earth, such as static current and leakage current.

What is the best grounding system?

It is not possible to determine which grounding scheme is best to be used, each one has its uniqueness, so it is necessary to analyze each situation, such as where it will be used and what the standard requires for each situation.

We hope to have answered all questions about electrical grounding! If you still have any questions on this subject, leave it in the comments!