Originally Posted by P-J
Try this idea: The scene is a farm with a barn on the property. The electric power is set up and delivered to the house. Power to the barn is run on overhead wires delivering 120/240V. In every case, the power is delivered as a 3 wire system and ground at the barn is established at that service panel using a grounding rod.
...And how that ground is provided is determined by local code because they know the local ground conditions. For example, here in North Alabama the ground would be through two ground rods no closer than 4' apart.