Split phase

Split phase is a mains electrical supply system mainly used in America (where it is usually and incorrectly referred to as two phase). It is used occasionally in the UK in distribution situations where only two 11 kilovolt phases are available, but it is rarely taken into buildings.

A transformer providing split phase has a single phase input, and the output is centre-tapped with the neutral on the centre tap.

This means that there are two phase conductors both equidistant from the neutral. Therefore (provided the balance is good), appliances can be directly supplied with the normal voltage with some of the advantages of higher voltages, such as smaller cables and/or lower losses. It also means that appliances can be supplied that need double the normal voltage, so it is widely used for high power or European equipment in the USA.

A split phase motor is a type of induction motor designed for use on single-phase electric power, characterized by low cost, low starting torque, and high starting current. Such motors are chiefly used in blower applications.