Editing Distribution transformer (section)

===Secondary===
{{unreferenced section|date=January 2023}}
[[Image:Utility pole transformers.jpg|thumb|upright|A "transformer bank", widely used in North America: three single-phase transformers connected to make a 3-phase transformer.]]

The low-voltage secondary windings are attached to three or four terminals on the transformer's side.
*In North American residences and small businesses, the secondary is often the [[split-phase electric power|split-phase]] 120/240-volt system. The 240 V secondary winding is center-tapped, and the center neutral wire is grounded, making the two end conductors "hot" concerning the center tap.  These three wires run down the service drop to the building's electric meter and [[Electrical service panel|service panel]]. Connecting a load between the hot wire and the neutral gives 120 volts, which is used for lighting circuits. Connecting both hot wires gives 240 volts for heavy loads such as air conditioners, ovens, dryers, and [[Charging station|electric vehicle charging stations]].
*In Europe and other countries using its system, the secondary is often the three-phase 400Y/230 system. There are three 230 V secondary windings, each receiving power from a primary winding attached to one of the primary phases. One end of each secondary winding is connected to a 'neutral' wire, which is grounded. The other end of the three secondary windings and the neutral are brought down the service drop to the service panel. 230 V loads are connected between any of the three-phase wires and the neutral. Because the phases are 120 degrees from each other, the voltage between any two phases is sqrt(3) * 230V = 400V, compared to the 2 * 120V = 240V in the North American split phase system. While three-phase power is almost unheard of in individual North American residences, it is common in Europe for heavy loads such as kitchen stoves, air conditioners, and electric vehicle chargers.