Introduction

We have dug the well below and are now pressurizing the water and burying lines for winter, zone 4 in Missouri.

Design Rationale

Well with 1000-3000 gallon per day recharge rate is main potable water source for facility
3/4 acre pond up hill feeds agricultural operations
17' of vertical heaight in 40" well casing provide 52 gallons per foot, total of about 1000 gallons of storage
Normal operation: well water
Rural water for backup
Tee between rural and well water selects between sources
Pressure tank located inside house
Pressure switch and pressure gauge located inside pit right next to 6" well casing
240Vac power line comes from workshop, 90' away
Power line buried about 1' down with Trencher
Water lines buried 3' throughout with Backhoe

Can pressure switch and gauge be located in pit right next to well? Will it corrode due to moisture? Typically, the pressure switch is located on the pressure tank in the house, but here, our power system is located in the workshop. The workshop power feeds the house at 120VAC. The submersible pump is 240VAC. We would have to run another 240V line to the house and then to the well, which would add another 500' of wire to support the well - by extending our 240VAC line to the house. Instead, we can run the 24oV power directly to the well from the workshop.
What gauge wire do we need to run to the pressure switch for the 240V pump if the total wire run is under 100' from workshop?
Should we get a 30/50 PSI pressure switch or 40/60 PSI switch?