Build Daily

Electricity And Safety

August 12, 2017 18:07

What are the grounding system ?

To avoid electric shock when you touch the bare wires or damaged electrical equipment, the International Electrical Company (IEC), special protection has been developed, called the ground.Also, this system is standardized in the Russian GOST and a detailed description is available in the book of the SAE (device rules and operation of electrical equipment).What is a ground loop power grid?It's very simple, it is an additional conductor devices attached to zero.In the event of an accident, the breakdown of the insulation or the appearance of contact where it should be, phase energy goes on PE wire to zero, even in the event of accidental contact with the man will not be affected.Let us examine what are the types of grounding systems used in Russia.

Contents:
  • TN and its variants
  • TN-C
  • TN-S
  • TN-CS
  • TT and IT

TN and its variants

mostgrounding system common type - is TN, where zero is aligned with the ground throughout.This type is also called in the supply neutral to earth when a conditional zero N source is connected to the PE grounding device.grounding device is not difficult, but nevertheless technologically and represents a group of pins driven into the ground vertically to a considerable depth to the aquifer, from 2.5 meters or more.These pins are connected to the band or cable in single dwelling house ground loop.Consider what exists TN classification systems to date and what is the difference between all species.

TN-C

in the old housing fund is used to protect the type TN-C, is zero when N is also serves as a protective conductor PE, combined.This is the easiest and cheapest option electrical grounding to 1000 V.

TN-C scheme

type TN-C is obsolete and electrically dangerous because it has no separate protective conductor, and in the case of breakage of the neutral conductor, during the state of emergency, the full potential is onelectrical equipment, risking electric shock or fire.

TN-S

Therefore, in newly designed buildings using other subsystems TN-S, in this device there is a separate wire phase zero (neutral) and the protective conductor PE. conductors N and PE, from the substation to the earthed neutral are separate components of the electrical system.

TN -C

This type is the most reliable of the accepted type of ground power supply.Its disadvantages are the high cost, since requires additional conductor, from the substation to the consumer.

TN-C-S

Devoid of these shortcomings, in the implementation of a relatively simple system TN-C-S, which combines the advantages of the systems described above.It is also easy to implement during the renovation of old buildings.The point of this scheme is that the MSB is organized to TN-C system, then share the neutral wire PEN two conductors N and PE, further there is a TN-S system.

TN -C -S

disadvantage of this system is the same as the TN-C, in case of interruption PEN bus system is under full tension.With this lack of fighting installation of additional devices, such as voltage relays, emergency stop producing consumer from the network.

TT and IT

There are two kinds of supplies that are used in special circumstances, this type of TT - when electricity is organized delivery phase conductors from a source with earthed neutral, and ground is organized directly by the consumer.In this way, the connection is carried out mobile homes, temporary facilities.This type requires the mandatory use of protective devices RCD.

TT

Another option - IT system, supply the type that does not use earthed neutral.Zero source is connected through a special device with a high internal resistance, and is set directly at the consumer unit zero and protective earth (according to PUE 7, Chapter 1.7).This type of supply used in special laboratories as interference introduced in this way, the minimum.

IT

also recommend reviewing the video, which provided a description of each variety of grounding systems with a transcript of abbreviations:

What are the options for the protection of electrical installations up to 1 kV?
YouTube Preview

And finally, we want to pay attention - may not be used as a protective ground heating pipes, gas, water pipes, elements of metal fencing.In this case, the possible appearance of these elements of the total voltage of 220 volts, putting the lives of others in danger.Take care of yourself.

That's all that I wanted to tell you about the main types of earthing systems used in Russia.We hope you now know, what are the schemes of ground loops, and what's the difference between the existing options!

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