As I mentioned in first post, there is around 500 W on each PSU, they should be rated for 850 W. But of course I tried it running only with one PSU with 4 cards, but still the same, double PSU is not the case, not mentioning I have other rigs running that way just fine.
I will try to run it with only one GPU.

There is 230V/16A for each two PSUs, meaning 3680 W for each rig and 3x 230V/32A (22  kW) for entire house.