The difference between three phase and single phase is primarily in the voltage that is received through each type of wire. There is no such thing as two-phase power, which is a surprise to some people. Single-phase power is commonly called "split-phase. Single-phase wire has three wires located within the insulation. Two hot wires and one neutral wire provide the power. Each hot wire provides volts of electricity.
How to Make Up a 3 Phase Panel
3 Phase Panel Wiring Color Per Code - Schematic Wiring Diagram
Three-phase electric power is a common method of electric power transmission. It is a type of polyphase system mainly used to power motors and many other devices. A three-phase system uses less conductor material to transmit electric power than equivalent single-phase , two-phase, or direct-current systems at the same voltage. In a three-phase system, three circuit conductors carry three alternating currents of the same frequency which reach their instantaneous peak values at different times. Taking one conductor as the reference, the other two currents are delayed in time by one-third and two-thirds of one cycle of the electrical current. This delay between "phases" has the effect of giving constant power transfer over each cycle of the current, and also makes it possible to produce a rotating magnetic field in an electric motor. Three phase systems may or may not have a neutral wire.
Three Phase Panel Wiring Diagram
The need for three-phase supply or service occurs when heavy equipments are present such as large motors beyond 5 HP motors , because such large equipments need high starting and running currents. Large buildings, plants and offices have greater power requirements than the power used in domestic installations. Therefore, generally they are often installed with three phase wiring or three-phase supply. The three-phase power service is generally used for high power rated equipments such as large air conditioners, high rated pump sets, air compressors and high torque motors. Therefore, it is rarely used for domestic installations, but commonly used in commercial buildings, offices and industrial installations.
But there is that rare exception to watch out for. It will tell you at a glance whether the service is likely to be be single phase or three phase. Three wires means single phase two hots and a neutral , and four wires is three phase three hots and a neutral.