Electricity has penetrated into all spheres of our lives, but its use is accompanied by a risk of electric shock. Their main causes damage to the insulation on the body, and a high voltage.
When you touch the body of the person receives an electric shock, which in severe cases can lead to death. Grounding and vanishing designed to protect against such hazards.
What is the difference?
Grounding is the direct connection of all the metal pieces of equipment, which nominally are not designed for the transmission of electric current, the grounding circuit of the property.
The vanishing based on the connection of these components with zero electrical bus network.
In the case of ground insulation in the breakdown appears current Ik, which is given immediately to the ground to inhibit the occurrence of high voltage to the metal device components, Figure 1.
When using nulling the housing sample equivalent to a short circuit, whereupon electroreceivers de-energized by operation of the protective device (automatic, cork) that Figure 2 shows.
If properly implemented, both the protection of species properly perform their functions. The differences between them are manifested in the fact that the Vanishing stress on the body is always strictly zero, and the residual potential may be present, usually by grounding constituting tenths of a volt.
Arrangement of earthing and neutral earthing
With the circuit point of view of grounding and vanishing are some differences, which Figure 3 shows. Chief among them - to implement the necessary ground 3-core cable. Earth conductor may have a somewhat smaller cross section as compared with the workers, and its isolation is always painted in yellow-green color.
One end of the ground wire is connected to the corresponding contacts on socket through which the ground potential is supplied to the body of the device to be connected. The second end is connected to the grounding bus switchgear panel.
the neutral conductor is also closed at Vanishing on the ground, as shown in Figure 3.
Determining the place of such a connection requires special knowledge and perform calculations.
Advantages and disadvantages
The very existence of two systems of protection indicates the absence of each of them decisive advantages.
The main advantage of vanishing - lower costs of implementation: it can be built on the cheaper 2-wire power cord.
Advantages of the ground - much better technical parameters. In particular:
- In contrast to the vanishing of that stops working when you switch on the power wires to the phase-to-neutral, grounded always works.
- Vanishing works reliably only when a short circuit phase to the housing.
- In case of breakage or burning-off of the neutral conductor to shield the protective effect of vanishing completely terminated. For grounding conductor this event is much less likely because it is in normal mode does not conduct current. Therefore vanishing requires constant monitoring, and ground maintenance is limited to checking once a year tighten the nut point of connection wires with the shield contact.
- The grounding allows the use of a part of RCD wiring.
- Correctly identify the place of execution of the neutral wire connection to the ground, which provides a normal efficiency of the protective effect of vanishing, can only be an electrical engineer.
conclusion
In new homes and apartments, as well as the overhaul of the organization is strongly recommended grounding. In older homes with two-wire power wiring should be replaced as soon as possible on the three-core with normal ground organization.