Great Topic!
I’m Not an electrician, but have given myself a few AC Zaps over the years. 
However, as for 10mm2 wiring, I assume you talking AC Wiring from the Power Box back to the State Grid ?
Interestingly, out at the end of a power line at our Remote/Heritage Property, there is only One Hi-tensile Steel Wire tightly strung between power poles. The Single strand Wire looked like 8guage Fencing wire, but specially made I suspect. Helicopters fly over the line a few times a year to search for Hotspots, I was told.
This single line supplied 240V to the homestead (240Vx15Amp = 3’600kWh Energy), I think there was Hi-voltage 480VAC Power Transformer across the Valley, like modern Distribution lines. As we ran 2.5kW Water heaters, Ovens & washing machines etc. The Power came in on a single line.
As 3hp is 2.2kW line Power, Can one run a Single Steel Cable for AC Power in conduit (or high to code power poles) & install a Earth Spike to code where the Pump is installed ?
As I am lead to believe, the higher the Voltage the smaller the mm2 wiring required, and think that goes for AC or DC Voltage, Yes ?
That should Tell Everyone to Purchase a Battery with a minimum 10kWh Energy (or at least a battery bank to supply 24hr consumption). Currently a 10kWh LiPO4 Energy storage is under $5’000 for a single unit or under $8’500 for two.
Then a System owners will be Energy Independent & could easily & simply Replace the State Grid with a cheap 3.5kw $900 fuel Gen-set that would rarely used other than extended bad weather, as most Off-Griders know !