Normally a rig would have 6 to 8 cards which will take 400 to 500+ watt - having a few of these is like running a Water Pump, Geysor or heater. If you have more of these then it is like running an AC. The issue is with the Asics which takes 1500 watt to 4000+ watt.

Having a power socket with 15 Amp and 2.5 MM wire is more than enough. For 4k+ watt it is preferable to have a 4 MM+ wire and a stronger MCB else it might trip.

Think about the whole thing in terms of money - a rig with 8 cards will cost 3L+ and an asic that takes 4k+ watt input and gives 100+ THs of speed costs 10 Lac+. On the other hand one can easily buy solar power that costs half that money. Plan the process well and you won't have to worry about electricity so much.