Single phase isolation / distribution transformers.

Single-phase meaning power lines as an input source; therefore, only primary and secondary winding is required to accomplish the voltage transformation. In electrical engineering, single-phase single-phase distribution transformer is used when loads are mostly lighting and heating, with few large electric motors. Most household loads are single phase. In Canada, US and some other countries, three phase power generally does not enter homes. Even in areas where it does, it is typically split out at the main distribution board and the individual loads are fed off a "single" phase. When single-phase electricity is needed, it is available between any two phases of a three-phase system, or in some systems, between one of the phases and ground.