Is this true throughout the United States, or do you also use 3 phase and only take one phase into domestic properties, like Europe ?In the USA, the power company's transformer has three outputs; L1, L2, and Neutral.
In my area (which is somewhat rural) the power company's lines are 3-phase 60Hz with neutral, somewhere between 11kv and 22kv. However, the neighborhood power transformers just use one of the three phases and Neutral on the primary. The secondary winding is split-phase. Without the Neutral wire, we would just have 240VAC 60Hz.Is this true throughout the United States, or do you also use 3 phase and only take one phase into domestic properties, like Europe ?
This could be the case where you live.Because the underground cable is buried and usually has a metal sheath it can easily provide a good earth connection.
In the States, transformers on poles are generally grounded via the supporting cable, which are usually galvanized steel. I have no idea what resistance they might be.Overhead supply is inherently without an earth. Supply companies do not run an extra wire for this.
by Aaron Carman
by Jake Hertz
by Jake Hertz