Lets say for example you were a runner and to qualify for a race you had to run 3 miles in 30 minutes.
Youve trained all your life and you can run 3 miles in 30 minutes but thats the very best you could ever possibly do, so you run the race and you qualify.
Now, imagine you have to run that same race pushing a wheelbarrow along in front of you loaded with bricks.
Theres no possible way your going to run that same race in the 30 minutes that it takes to qualify so what are you going to have to do?
Your either going to have to ditch the wheelbarrow and the bricks ( Decrease the Resistance) so you can run as fast as you used to, or your going to have to increase your strength to overcome the resistance your pushing to be able to complete the race in the same amount of time that you used to.
Hence the resemblence to using the earth to try and clear a fault.
If the earth had very little resistance,the current could possibly flow quickly,or just enough,back to the neutral point, to facilitate tripping the breaker because the amperage could flow quickly enough to make this happen.
Problem is there is too much resistance in the earth and although the current flows as hard as it can through the dirt trying to make it back to the neutral point, it cant flow quickly enough to make the breaker trip. Therefore you cannot depend solely on a "Ground or Earth " return path to have low enough resistance to make the current flow high enough to make the breaker trip to clear a fault. Not sure but I think the power company's high voltage lines may be able to make this happen, but like the runner, the voltage (Strength) is so much more that thats a different scenario.
Do like I would do in a race like this, go ahead and grab your wheelbarrow full of bricks (The connection to Earth as its required), enter the race, and once the race begins and the gun is fired in the air, (Ground Fault) take a short cut (Ground to Neutral Bond) and unless something odd happens you'll get
