The three phases that come to the pole from the substation are not 120v. The can on the pole at the bottom of the yard contains a transformer, the output of which is centre tapped 240v. A cooker, and other high power appliances use the full 240v, whereas the two 120 volt lines are fed to lighting and power sockets, each of these phases (which are 180 degrees apart) are fed to different rooms, according to a plan decided by the house builder. When I lived in Michigan, I discovered that two outlets next to each other in the basement were fed by different phases, so I was able to connect to both for the purpose of feeding my 240v UK power drill! I also fitted a UK socket in the kitchen, as the laundry room wa the other side of the wall, and used that to power a European kettle, which heated much faster than a 120v kettle!
One March in Indiana about 30 years ago, we had an enormous snow storm that brought the cables to the house down for days. I discovered that one phase was still working, but the one that fed the central heating was severed. So I wired the heating to the other phase temporairly, and we had heat. We were cooking on a small camping stove for several days. When men arrived at 3:00 am some days later we heard them entering the back yard and exclaiming about the damage (several trees had been brought down) in very colourful language! When the snow melted, I had to cut up the downed branches and cart them to the place that the city designated. I couldnt get anybody to do the work, as the tree people were all overloaded!
David