Help make a diagram of the distribution panel

Oleg asks:
Good evening everyone! My little son, he is thirteen years old, a big fan of YouTube videos on electrics. In the summer we are going to build a small house, on a plot of 60 square meters. m., son himself, on the basis of the watched video channel "Notes electrician" depicted the distribution panel diagram, power 15 kW, for the future house. I’m not very strong in electrics, although I got a general electrician’s crust, but it was still in the USSR, and I got it, at a marine school, at DOSAAF courses, in front of the army, sent there from the military registration and enlistment office. Well, people of my generation will understand me, they know this whole gimp. In general, I did not work a single day in this specialty, and therefore we are contacting you. Please see what we did right and what not. Advise. We also have several questions on this scheme:
1. Is it possible to drive a working zero from the input machine not to the bus, but directly to the voltage control relay?
2. Did the little son choose the ratings of the circuit breakers?
3. Did he correctly distribute the load in phases?
4. Are wire cross-sections selected correctly?
5. Is it necessary to ground the switches to the light if the TN-C-S grounding system is selected?
And another question, if possible. What can you recommend Three-phase voltage relays, with displays and which are installed without contactors, otherwise only two DigiTOP and Euroautomatics were found. Thanks in advance. Little son is worried, because this is his first exam.

The answer to the question:
Hello, regarding: 1. it is possible; 5 - to be honest the first time I hear that they are grounded. Usually no one does this.

On questions 2, 3 and 4, there’s a small snag - the circuit has attached itself in a small resolution and I can’t see it very well, you can send it through the cloud, for example. But what I saw:

- Everything that through the outlet (washing machine and roses. Groups) to 16A should be, and the wire is 2.5 mm². This is exactly so for you (but I repeat that I can’t read everything, as it’s shallow).

- Wire cross sections where 4 and 6 mm² from automatic machines 25 and 32A are correct. But it’s not clear how you enter 4 poles at 25A, and the sub-machine is lower (the right side of the circuit, it seems there is written “electric stove” but I can be wrong) at 32A ??? How can it be more introductory? Maybe a typo?

With zeros at the input, it is not clear why 3 zeros come out of the input 4-pole AV, and the bus is not clear why? Or does it leave 1 zero and simply draw it so that it goes from the machine to the bus, connects to it and passes behind the machine to the LV?

Pay attention to the products of Meander and Novatek, but Euroavtomatika and Digitop are in good demand as well as good reviews of many electricians.

p.s. Write questions and send the circuit in a good size, though almost nothing to parse.

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8 comments

  • Oleg
    To answer
    • Admin

      you still haven’t answered my questions, everything seems to be fine according to the scheme, the only question is about the electric stove’s differet machine.

      To answer
      • Oleg

        Good evening. About the differential.machine for electric stove. Here, frankly, I myself am in doubt, on the one hand, the power of the electric stove is 7.5 kW, sort of like a cable of 6 square meters. mm and the differential for it 32A converges, and on the other hand, the differential automaton in 32A, will be larger than the input automaton by 25A, any meaning of its installation is lost. And tell me, for a plate with a single-phase connection with a power of 7.5 kW. differential automatic 25A suitable? Or have to invent something? And yet, I wanted to ask about the fire protection RCD, I want to put it in the metering board at the output (ShchU input: three-phase, three-pole circuit breaker for 25A, three-phase Mercury counter, fire protection at the output) What rating should this RCD have in order to to maintain selectivity, with RCDs operating in the RC. and what is the breaking capacity, in this case it is better to choose 100 or 300mA?

        To answer
  • Oleg

    Dif automatic machine at 32A (electrician’s advice from the forum, said that differential machines are selected in the same way as RCDs), I don’t understand the input 25A, that is, it turns out that if something happens, it will work? And you can, on the stove 7.5 kW. put the differential machine on 25A, will it be enough?

    To answer
    • Admin

      This is a strange trend "difavtomaty are chosen as well as UZO" - meaning that a step higher in nominal value from a higher machine? Why spread it on the differential? Do you know that the differential performs the same functions as the machine + RCD functions, that is, protection against overload and leakage? It turns out that by setting the Dif on 32A (it is not clear how they are chosen and what kind of electrician advised the forum ...) you lose the protection of this group and cut it off when it is overloaded. That is, you ALREADY lose what you ask for selectivity and RCD. But not only for RCDs, selectivity is needed, but also for machines (more on this later).

      Power is calculated by the formula:
      VOLTAGE MULTIPLE TO CURRENT.

      To find out whether it will work with a machine with a certain current, we do the opposite, we calculate the current consumed by the stove in full power mode:
      POWER DIVIDE FOR VOLTAGE
      Total 7500 watts divided by 220 volts and get 34A.

      I think you already understand that it will not work on the 25A machine. Rather, it will work, but turning on all burners and the oven at the same time will not work. And how can you control that the one who cooks does not load the entire stove? And why would this person (I believe his wife) have such a stove in which all the burners cannot be turned on?

      To understand "it will work or not with a single-phase connection" you should determine how much each burner consumes, maybe all 4 burners consume less than 25A in total (this is about 5 kilowatts) and then use it for health. Oven unless you have to include it separately. But most likely this is not so, the oven power usually lies within 1-3 kilowatts, if you are lucky and you have an oven, say 2.5 kilowatts, then with a total power of 7.5 kW, we conclude that the burners will consume 5 kW. In general, this information is possibly in the description of your stove (look in online stores) or in the instructions for it. For example, even on a gas stove, the instructions indicated the power of the gas burners.

      But what can you “invent” in this case? Do you have an old or modern electric stove? In modern ones, it is often possible to switch jumpers and make a three-phase connection, then it will work, as they say, "with a bang." And in modern ones, if there isn’t any electronic control there, then you can often “re-farm” to a three-phase connection. Another question is whether you can do this so that you are confident in the safety of the connection? Do not forget about security.

      As for the fire protection RCD, you can calculate the length of the wiring and natural leaks, or you can just put 300 mA. Talking about selectivity in home shields is tantamount to raving. It is very difficult to achieve, especially when it comes to machines. With RCDs it is a little simpler, but for selectivity there are selective RCDs - the same as usual for currents, but they work with a longer delay.That is, if a group RCD does not work for a leak, then a selective RCD at the input will work. Selective in catalogs of shops are denoted by the letter S.

      And I just noticed, you write "UZO S32A" - where did you meet the UZO with a letter before the face value? It is only with automatic machines that the type of time-current characteristic is indicated in front of the rating (B and C are the most common in everyday life).

      In general, I look forward to hearing and continuing our conversation!

      To answer
  • Oleg

    Good evening. Thank you for the detailed answer, in general, everything is clear, if you put a 32 Ampere differential machine, then with a 25 Ampere input machine, the meaning in installing it is lost. So you need to set the maximum of the differential automaton to 25 A, that is, as I understand it, the introductory automaton will be C25A, and the differential automaton B25A, will that be true?
    By the word “invent” with an electric stove, I meant either buying an electric stove of lower power, or bombing MOESK to increase the power of the input machine to 32A.
    RCD with a letter in front of the face value, this is of course a mistake, I apologize.
    And such advice is given by an electrician, as he positions himself, on one of the sites (the link was deleted by the moderator).
    Here they are on my questions: “Anatoly Alexandrovich (author) 02/28/2020 at 23:30
    The RCD at the nominal value was chosen correctly, the answer was corrected in the article above. The rated current of the differential automaton is selected similarly to the choice of the RCD rating (see in the article). ”
    And here's another, and this is already at the nominal value of the differential circuit breaker for an electric stove: “The rated current of the network must be less than or equal to the rated current of the circuit breaker (difvomatomat), and the rated current of the circuit breaker multiplied by a factor of 1.13 must be less than or equal to the long-term allowed cable current.
    1.13Itav Id
    Long-term allowable cable current with a cross-section of 4 mm2 - 34A, therefore, for networks in which small but prolonged overloads may occur, the rating of the circuit breaker (difavtomat) must be selected 40A.
    For networks in which the possibility of occurrence of small but long overloads is excluded, the condition is met:
    Ip ⩽ Iav ⩽ Id,
    in this case, you can put a protection with a rating of 32A. "

    A fire protection device, 32A; 300mlA where is it more convenient to put at the exit from the control room or at the entrance to the control room?

    To answer
    • Admin

      “So you need to set the maximum differential machine to 25 A, that is, as I understand it, the introductory machine will stand C25A, and the differential machine B25A, will that be true?”

      Well yes. If you do not find B, put C (where to go?).

      “By the word“ invent ”with an electric stove, I meant either buying an electric stove of lower power, or bombing MOESK to increase the power of the input machine to 32A.” - correctly…

      Regarding the advice about the choice of RCD and Dif - maybe he was just mistaken and we are scolding him in vain.

      About the current - right. If it’s shorter, the stove should “eat” less than the machine can “give”, and the cable should be able to pass MORE than the machine will “give” and “eat” the load.

      Those. the load takes as much as it needs, and our task is to provide the circuit with other components so that such current can safely flow through the cable and the machine does not turn off.

      And here is the further contradiction of the above about 1.13In and the rest.

      "Long-term allowable cable current with a cross section of 4 mm.kv. - 34A, therefore, for networks in which small but prolonged overloads may occur, the rating of the circuit breaker (difavtomat) must be selected 40A. ”

      those. we will overload the cable so that the rating of the machine is 40A (already an overload of 6 amperes), and even the machine may not turn off for a long time with an overload of 13%, i.e. at current up to 45A (overload at 10A? ...

      “For networks in which !!! is excluded !!! the possibility of occurrence of small but prolonged overloads the condition is met:
      Ip ⩽ Iav ⩽ Id,
      in this case, you can put a protection with a face value of 32A. ""

      Those. and where is the “overloaded” possibility of overloading - will we make the protection more stringent and set 32A? Maybe the opposite then?

      To answer

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