Any private house, first of all, should be safe, and then it should be comfortable, cozy, reliable, etc. Therefore, the first thing to look for when designing a home electrical network is the system grounding. And there are several of them and the regulatory documentation will help you quickly understand this issue, namely PUE - the rules for the installation of electrical installations.
What are the grounding systems
If the concept of a ground loop is covered in obscurity, then chapter 1.7 will help to dispel it. All necessary information is detailed in paragraph 1.7.3 of the PUE.
- TN. A system in which the ground loop is located separately, and all consumers are connected to it. TN is also called a solid grounded neutral.
- TN-C. There is a well-known system of "zeroing", in which the working and protective "zeros" are connected together. Most often used in apartment buildings of the last century.
- TN-S. Here the working and protective "zero" are separated along the entire length of the line. This means that the conductors do not touch in the interval from the current source to the consumer.
- TN-C-S. Zero conductors are aligned, but not on the entire line (as in the TN-C system), but only on its separate section.
- TT. In such systems, there are 2 ground loops. The first through the working "zero", and the second - directly to the consumer's sections, on which a separate ground electrode is "thrown".
There is also the less popular IT grounding system, in which the working neutral conductor is isolated from earth, or separated by a high resistance element, which is almost identical. Other parts of the consumer are connected to a separate ground loop.
Which grounding system to choose for a private house?
The answer is unambiguous and obvious: the best and safest grounding system for a private house is TT. Only then can we talk about safety when the local electrical wiring has a separate, unconnected circuit. But not everything is so simple, and there is a moment that requires periodic monitoring.
With a TT system, it is necessary to check the quality of the ground loop several times a year. Do not forget that its metal parts are in the ground, and at any moment, they can simply rot. The integrity of the contour will be violated, respectively, and the quality of contact with the ground will become more negative than positive. Therefore, it is better to call specialists in advance and keep this feature of the TT system under control.
You can, of course, check the grounding yourself, but this will require at least a special device, the cost of which is quite high.
TN-C - the least reliable grounding system
They are trying to get rid of it, because if the integrity of the working "zero" is violated, the entire protective net is under potential that is dangerous both for health and for life. The splitting of the working zero conductor only creates the appearance of safety, but in fact it turns out to be quite the opposite. Therefore, when designing an electrical network, it is better to postpone TN-C as the most unworthy.