How the Earthing Process Becomes Perfect Now
If the device casing is not connected to the earthing conductor and inside the device for unknown reasons, there will be a “puncture” and the electric potential appears on the casing, this potential as it is not connected in any way to the ground (directly or indirectly), has nowhere to “escape”.
The risk is therefore obvious. A man approaches, who has an electric potential at the level of 0V, touches, willingly, wanting a housing that has a potential of 230V, which in effect causes that a person begins to flow a current of such a voltage. You can choose the residential electrician for the task.
To sum up the answer to this question,the combination of all devices with the ground, as a result, prevents the long-term maintenance of electric potential on the housings (and other elements) that are available to man during normal operation of the device (ie when the casing is closed). In the event of an electrical breakdown on the casing, when the latter is grounded, a short circuit will occur, which in turn will trigger the overcurrent switch (not to mention a residual current circuit breaker, if it is installed) in the home switchgear and disconnect the voltage before anyone it will touch the housing.
Symbols and symbols
In the case of cables, you can meet two basic signs:
- PE – marking the protective conductor (yellow-green color – more in the article)
- PEN – designation of the neutral conductor, which also acts as a protective conductor (blue)
If you are talking about symbols, then in the case of grounding you will encounter two of them most often:
In many devices (very often in “small” appliances), instead of a power plug with earthing, you will notice a plug in which there is no hole for the grounding pin. This does not mean that the device does not have protection against electric shock. The device’s housing usually has a so-called the nameplate on which you can encounter the symbol of two squares (one inside the other). This means that the device does not have any conductive elements available (the casing is usually made of plastic) and hence there is no need to ground it.
The presence of a plug without a hole on the grounding pin is not synonymous with the fact that the device has the proper protection against electric shock. Only the above symbol informs about this fact.
When it comes to home electrical installations, we have four basic network layouts. The main difference between them is the way of grounding:
- Supply network without earthing installation (expert TN-C).
- Supply network with a separate earthing installation within the flat / house. In the home switchgear, neutral and protective conductors are connected to each other (TN-CS).
- Supply network with a separate earthing installation, grounded in the same place as the transformer’s neutral point (TN-S).
- Supply network with a separate earthing installation grounded in a different location from the transformer’s neutral point (TT).