Conductor Size for 20A Inductive Load & BTA41 600 with U209B Impact on Network

As in the topic, I am in the process of making a regulator for the welder, but I wonder what wires should be used to connect it - the load is of course inductive. As you know, samorobki causes are quite non-linear when it comes to power consumption, does such a regulator based on bta41 600 and u209b cause any negative effects in the network supplying the current to the generator? are there any surges or tics?

Someone can tell me using this scheme:
http://jony1230.webpark.pl/sch.JPG
what happens if i switch phase with zero? the welder will be used in different sockets ...: /

As for the value of the conductor cross-section, I'm going to use 2mm for now if something like this is enough, it will be about 20cm long, please provide some link to the tables containing the values of the maximum currents for a specific cross-section for the future :)

Thank you in advance for your help

Practically, for a freely laid conductor, 10A / mm2 can be assumed. On the other hand, in the transformer it is approx. 2-2.5A / mm2. (for copper).
Here you can find out more about the load capacity http://www.systemyogrzał.pl/projektowanie/pomoce_projektowe2.asp?id_artykulu=107
http://www.elektroinstalator.com.pl/artyk/2004-7-8/06_kryteria.htm
The welder will work properly with the replaced wires in the socket, but there must be a third wire from the body of the welder to the grounding pin in the socket.

ahh, because the output voltage will be increased ...
I already know it, I had to do it more than once before I realized what was going on: / I just welded when it rained and at the output "zero" there was something around 100V: / damn, I used to think about this idea because, unfortunately, I do not have sockets with real grounding: /

from what I see, the given table is for single-core cables and I have multi-core cables, they simply fit better ... how do these dependencies look then?

Carefully look at the table there are current values for a multi-core installation. From 1 to 6 wires, current is given in the white fields.
http://www.systemyogrzał.pl/projektowanie/pomoce_projektowe2.asp?id_artykulu=107

I think I have a bad perception of monolingualism that is, it makes no difference whether the conductor is made of solid copper or also a large number of small threads? is it just the cross-section?

Yes, the cross-sectional area counts regardless of the number of wires in the strand.

The parameters of the welding machine power cables depend on what percentage of the welding machine efficiency you have taken (10% 20% 40% or more)
The OZAS minimag 250A with a three-phase power supply and 5m cables has a cross-section of 2.5mm kw and this is quite sufficient for longer lengths of the power cable, the cable cross-section should be increased to 4mm kw, but not due to heating but voltage drop

The multi-strand conductor is important, but it is for high frequencies and high voltages when the phenomenon of the so-called "SKINNESS" Then conducts a cable with a large number of threads that are best insulated from each other much better than a single core with the same cross-section

ok, it clears it up a bit ...
because the fuse behind the clock I have 16A, so probably the current will not exceed this value, but I prefer to add a little because already vertically one 20 fell for unknown reasons