At the transformer provided by your utility company you get 240 volts. For some purposes the USA & others believe you don't need 240 volts. Here we cut the sandwich in half. The transformer secondary is center tapped. We get 120 volts from either half of the transformer secondary winding.
To utilize both 120 & 240 volts we need 3 conductors.
From the transformer to your single family house you have three conductors. One conductor (the center tap) is grounded at the utility transformer & again at the service on your house.
If this is done properly, the ground includes concrete foundation reinforcing steel, any conductive materials in contact with the ground, any metal underground water supply. I'm sure I failed to mention some component. If others aren't available we add grounding electrode(s).
Everything downstream from your service disconnect needs 4 conductors & we isolate grounding from grounded. These two words sound related, but are very different. The center tap (grounded) conductor is current carrying. We do NOT want grounding conductors to carry current.
Pump Guy, I believe had a building originally supplied with a cable with two insulated conductors, enough to be code compliant for 120 volts. A dairy farmer could use his cable to derive 240 & 120 volt power, he'd brag about how dangerous it is.
The other problem Pump Guy has is cable size.
I recently learned a bit about compressor motors. It has been common knowledge many years that code numbers denote efficiency. My air compressor looks identical to the one at our volunteer fire house. Mine was bought second hand. It had come from an industrial supply. The compressor at the fire house came from Tractor Supply. When we had problems with the one at the fire house starting on utility power, & stalling a generator plenty big enough, I questioned why. I found the run capacitor was bad, replacing it helped. Then I learned the Tractor Supply compressor was supplied with same motor except code L, where mine is code G.
Code L requires 9 to 10 times full load current to start. Code G needs 5 to 6 times full load to start.