Difference between Single Phase and Three Phase Power

July 11, 2015 by Editorial Team

Power comes in different phases. You could be using single phase power while at home and  three phase power at work. Single phase is the most common system and is mainly used in homes, while a three phase system is common in industrial or commercial buildings where heavy loads of power are required. What is the difference between a single phase and a three phase power system? This article will help you differentiate between the two.


singe phase power
A pole with single phase power transmission

Single phase power has three wires with alternating current. The current flow and voltage change in direction and magnitude goes cyclically at a rate of 60 oscillations per second. One wire typically carries the power and the other is the neutral one. In the US, households are commonly fitted with a 120V power circuit that has a 120V power wire and a neutral wire. Some countries have 230V as the standard power for single phase connections where one wire is neutral and the other is the 230V power wire.

Three phase power
Three phase power line

A Three Phase Power system is one where there are three currents that alternate. The power circuit comes in four wires, where three of them are power wires and one is neutral.

Comparison Chart

Single Phase PowerThree Phase Power
Has three lines ( one power + one neutral + ground)Has four wires (three power + one neutral )
Expensive in terms of labor and equipmentCheap in terms of labor and equipment
Commonly used in householdsCommonly used in commercial premises


The difference between these two phases is in the cost of installation and maintenance, common use, and amount of power load.

A typical single phase power system contains three wires, a power wire, a neutral wire and an earth/ground wire. A three phase one, on the other hand, comes in three power wires, a neutral wire and an earth/ground wire that is often optional.

For three phase, power can be drawn either by the delta configuration or the wye configuration.  Two of the power wires are combined to create a circuit in delta configuration, and a neutral is combined with any of the power wires in the wye configuration. A delta configuration produces 208V and the wye configuration produces 120V. This kind of flexibility helps balance power for different equipment in an establishment. In addition to its flexibility, three phase power is safe and requires less equipment and labor to handle.

The single phase power system is commonly used in households for lighting and powering appliances. It has a limited power load that is needed in commercial or industrial buildings. A three phase system is convenient in commercial or industrial buildings as it delivers heavy loads of power.


Here is a video that explains what a three phase power system is and its applications: