What section to choose a wire for grounding?

Ivan asks:
Countryside. The air line is single-phase. From the house goes to the line:
1. Automatic 25A + Separate grounding bus
2. Wire
3. Street vending machine 25A
4. Counter
We plan to make grounding according to the TT-scheme.

Those. we have a separate ground bus in the meter in our meter, all new wires are connected to the ground there. You can tell which wire (how many lived and what section to take) to the street vending machine. I wanted to take on 10 mm2 (with a margin of 🙂), three-wire, but I read the articles and realized that it is recommended to ground more than 10 mm2 from the shield.

Those are two options:
1. 3 core per 10mm2, then put one core to ground.
2. 2-core at 10mm2, and separately single-core at 16mm2, buy copper wires, except air duct, before grounding

The answer to the question:
In the sense? From the VLEP to the introductory automatic machine, SIPs are pulled over the air, where are you going to put the 3-wire? Are you going to pull 1 core from the bus to the ground electrode out of it, and the remaining 2 from the house to the street machine? NO.

There is a 2-wire circuit between the machines, a separate wire to the ground. If the earthing switch is located near the shield with a "street" machine, then a three-core can be.

the cross-section of the grounding conductor with a cross-section of phase conductors up to 16 mm² should be equal to the phase conductor, as this requires PUE (Table 1.7.5)
. This question was discussed in detail in this article. https://our.electricianexp.com/en/provod-dlya-zazemleniya.html .

(1 votes)
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2 comments

  • Ivan

    I have such a scheme.

    If you separate, as I understand it, it’s enough for me to take the same 10mm2 to ground
    Those total:
    1 cable. Two-core - 10mm2
    2 cable. Single core - 10mm2

    To answer
  • Ivan

    The point here is that between the home and street shields to throw a cable and there may be grounding with it, so as not to drag two corrugations.
    I will add also that I have the first shield of the house, and the street one is outside and there will already be an exit from the ground under it (planned so).
    I’m not going to pull out the core separately 🙂

    To answer

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