There are several options for grounding systems. These include TN-C, TN-S, TN-C-S, IT, and TT systems. Grounding systems have their own markings. Their explanations are as follows.
The first letter of the system symbol indicates the nature of the grounding of the food source:
T (Terre-ground) - connected to the neutral ground of the food source;
I (isole-insulation) - all non-conducting but conducting parts are isolated from the ground.
N- zero working wire;
PE- zero protection wire;
PEN- combined (joint) zero working and protective earthing wire.
The second letter in the designation indicates the nature of the grounding of
non-conducting but conducting parts of electrical installations of the building:
T- indicates the connection of non-conducting but conducting parts of electrical installations of the building to the ground, regardless of the nature of the grounding of the power supply;
N (neuter-neutral) - non-conducting but conducting parts of electrical installations of the building are connected (reset) to the neutral of the power supply.
The letters after the hyphen after the letter N indicate the method of setting the PE zero protection and N working wires:
C (combined-connected) -wire functions are provided by a common PEN;
The function of S (separated-separated) -PE zero protection and N working wires is provided by separate (individual) wires.
TN-C grounding system
The TN-C grounding system is one of the first grounding systems to be more economical and simple. Throughout the circuit, the ground and neutral wires are connected in one wire. The main disadvantage of such an earthing system is that phase voltage occurs in the body of the device when the zero wire is broken there is a danger of coming. In other words, in this case, the uninsulated phase. If the wire falls into the body of the device, the first person to touch it is the "zero wire" and the current will pass through it. This is very dangerous.
TN-S grounding system
The TN-S grounding system is much more complex than the TN-C system.
In this system, the ground and ground wires are separate (individual) throughout the circuit.
The circuit includes an additional ground wire, ie this circuit is connected to the ground with an
additional wire. In a multi-wire house, this wire is connected to the ground at the transformer substation. This is a more modern and secure system.
TN-C-S grounding system
In the TN-C-S grounding system, a separate ground wire PE and zero wire N are provided and they are electrically connected to a PEN wire at the input. The TN-C-S grounding system is almost a modernized TN-C system.
IT and TT grounding systems
IT and TT earthing systems are practically less used in everyday life. In short, these systems are used when there are special requirements for electrical equipment. It is possible to come across a small TT system in the home, but the IT system is almost non-existent. The IT grounding system is designed for laboratories that conduct experiments with sensitive devices while minimizing the effects of all-electric and electromagnetic fields. The TT grounding system is used during the construction of private houses.
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