The TT earthing system helps keep your home safe. It has a wide range of distribution, and is used in places where the TN-C, TN-C-S, and TN-S grounding systems are not fully provided. It is necessary to use this system if the overhead line is in unsatisfactory condition.
Today, most air lines are in poor condition. Most supports do not have additional grounding. This TT grounding system is also actively used to protect people from electric shock through metal surfaces. These surfaces include:
- Construction cars.
- Metal containers.
- Rooms that have a dielectric wall surface.
If you are interested, then read how to ground the car.
TT earthing system and its principle of execution
The principle of the TT system is quite simple. It is based on the fact that the protective conductor PE must be earthed independently of the neutral conductor N. Communication between these conductors is prohibited. Even if the ground conductor of the neutral conductor is located nearby, the protective conductor must be grounded through its ground loop. These contours should not be in contact with each other.
Thus, you can completely insulate conductive surfaces. Installing the TT grounding system is quite simple. Here is a diagram of the TT grounding system to help you complete the installation.
To install the system you need to conduct a protective conductor PE around the entire perimeter of the building. The conductor should be in the form of a plate or bar, which should be connected by a separate ground loop.
It is important to know!!! It is forbidden to connect the grounded parts of the structure and the housing of the electrical equipment with a working neutral conductor N.
TT earthing system requirements and features
Now we will list the main features that will help to complete the installation of the system:
All group lines must have an RCD whose setting must be no more than 30 mA. This is necessary to protect against indirect contact with live parts. It will also help protect your life when faulty wiring occurs.
- Zero conductor N
The neutral conductor must always be connected to the local ground loop and PE bus.
In order to protect all devices from overvoltage, you need to install surge arresters. You can also set surge suppressors.
- Ground loop resistance
This resistance must fully satisfy the PUE. In order to determine the effective resistance, it is necessary to measure the grounding resistance. To meet these requirements you need to use one vertical earthing switch in the form of a corner about two meters long. If necessary, you can make several grounding conductors. The ground loop in a private house can be connected to this system.
TT grounding system drawback
The TT grounding system has a number of advantages, which we talked about above. It may also have some disadvantages. To date, the fact of failure of the RCD and phase breakdowns to the grounded case can be considered a natural drawback. In this case, all conductors will be energized.
This can happen because the circuit breaker will not trip when the phase is shorted to PE. A single defense that will cope with this problem can be a potential equalization system. Only TT specialists must install the TT grounding system They have the necessary experience in this field.
We recommend to your attention: grounding system: TN-C-S.