The choice of accessories for the electrical panel for a private house and sauna

Roman asks:
Good afternoon, there is an input network - from an automatic machine - 3ph C 40A on a pole. In your home: we have 1 entrance shield and 2 floor guards.

In the entry plate:

as the first option - set the 3ph Dif machine 30mA, they say that at 15mA the leakage current it already turns off. Suppose the load is up to 3.5 kW = (16A * 0.4mA) = 6.4mA total leakage current. If you take the cable to the maximum, the whole one I buy (1000m * 10mkA / 3) = 3mA per phase (0.4mA at 1A and 10mkA at 1meter taken from open sources). Separately, I want to power - an electric oven, a sauna on my 3ph differential machine 40A 30mA

1) Is it possible to put three single-phase Dif machines in the input panel instead of a 3-phase Dif, after them 3 single-phase Voltage Relays, and then combine in one cable for example VvG-P-ng (LS) 5 × 6 (N, 1ph, 2ph , 3ph, PE)? And transfer to the floor shields, and there to distribute the load. Will it be right? or is it better to use three-phase and Dif and Voltage relays in the input panel?

2) Is it possible to combine three phases zero and ground in one cable?

3) Have I made the calculation of leakage currents correctly and will the Dif machine not knock out and will it perform its functions?

4) If the three-phase stove in the sauna 9 kW - ((9000/380) * 0.4) = 9.6 mA leakage current,
and 5kW single-phase oven - ((5000/380) * 0.4) = 9 mA leakage current.

It turns out they can not be included together, eating through one differential power supply?

Does a three-phase differential current have a leakage current of 30 mA on each phase? those. 9.6 need to be divided into three more?

5) Do I understand correctly that the leakage current will only be on the cable under load?

6) For an electric oven from a floor plate I’m going to forward a separate 4kv cable, a 24A machine and a special outlet.

Is this enough for a 5kW oven or is it better to throw a 6kv cable and a 32A machine?

The answer to the question:
Hello! on issues:

  1. It may be so, but why? Put on the input a 3-phase differential and a three-phase voltage relay.
  2. Yes. For something, there are cables with 5 cores.
  3. Will not be. If you put a differential with a leakage current large 2 times. (you can read as a guest about tripping currents. the indicated 30 mA can operate at 15 as well.
  4. Yes, right. Put a differential or RCD in the sauna with a leakage current of 10 mA - if there are false alarms, replace it with 30 mA. The oven is similar, but you can immediately 30 mA. Why not together? It is possible, but why? 5 kW oven? Maybe it's an electric stove and not an oven? If so, then according to SP 31.110, the electric stove must be connected to a separate line (separate cable + differential or ouzo + AB)
  5. No. Leakage current along the length why then consider? Leakage occurs through insulation, especially when it is aging and damp.
  6. Well, you asked above to one differential ... Put separate diffs and this question will be solved by itself. Enough for the cross section. But the automatic machine at 25A, maybe, but not at 24? 6 sq and 32A - this is with a margin of "to be sure." In principle, even, perhaps, is preferable. But not necessarily.

Add a comment