At various electrical network sections can be used unlike each other organization scheme ground, which immediately leads to the problem of the organization and the correct execution of the transition between them. In the residential sector is a typical case of occurrence of such a situation - pairing the ground wiring section systems from the substation to the panel ASPs residential building and subsequent intrahouse wiring. In the schematic form shown in Figure 1.
Such a shift in the practice of building a power supply networks is not uncommon, due to the following circumstances:
- the first of these sites is most commonly used TN-C system, which is the most economical in terms of capital expenditures for its implementation;
- in-house power wiring must be based on schemes TN-C-S, TN-S, which completely satisfy the requirements of the current version of the Rules of electrical devices (PUE).
The very process of transition from one scheme of laying the ground conductor to the other, which is formed by two separate wires, is the special name of "separation".
Features of the division
Needless separation combined protective conductor PEN at zero N and protective PE performed on the input electrical installation. In this case, the protective conductor PE is sometimes called a main earthing bus.
With respect to individual homeowners as separation place naturally selected introductory panel for houses apartment buildings it is advisable to carry out this procedure at ASU.
After performing the separation of the opposite association wires N and PE is not allowed on that points directly point 1.7.131 PUE.
The separation can be performed both in single-phase and three-phase network. Principal differences between them are not available except for the number of phase conductors.
To eliminate unnecessary loss of electricity separation it is expedient to perform a counter.
Implementation of separation
Given the presence of the output division points of two different conductors procedure itself operate using two separate buses. One of them is designed to connect the main conductors, the second serves protective. Tires compulsorily interconnected jumper. jumper functions can be assigned to any wire or rigid tire material and cross section which coincide with the main.
Practiced installation N bus by insulators, whereas the PE tire is mounted directly on the body ASP. Example tire assembly shown in Figure 2.
Tires must necessarily be provided with appropriate labeling.
Or jumper wires on the bus, and serving the working protective conductors are fed from special cleaving tire which is designed for PEN-conductor connection., Figure 3. In the absence of a part of this part of the wiring bus splitter circuit breaker does not apply that It allows significantly increase the operational reliability of wiring reduction in the number of bolted joints in her composition.
Their ease of use reasons not install several safety jumpers N-type.
In the implementation of the transition wire PE and PEN advisable to ground again. For this purpose involved specially organized by ground loops or grounding natural character. This feature is stipulated PUE in paragraph 1.7.61. The parameters of this species of ground current regulations are not defined, but, based on common sense and taking into account the functions performed, makes perfect sense to provide minimal resistance. As a guide can use a value of 4 ohms.