## Definition/Concept

The wire that actually contains the maximum voltage of the system with respect to any lower potential is known as Phase Wire or Live Wire or Hot Wire. I mean to say you will get the highest voltage across phase and neutral or phase or ground. But in the case of a neutral wire, identically, you will get zero voltage between neutral and ground. So you may understand the difference between phase and neutral. In simple words, we can say the phase wire conducts electricity from the power source to load and the neutral wire helps to complete a circuit.

## The function of Phase Wire

As we discussed before the main function of the phase wire is to carry the highest voltage or potential and to conduct the electricity from the power source to the load. Basically, an electrical load is connected by a minimum of two wires. For a single-phase system, a phase wire or a neutral wire is used. Although the direction of the flow of current changes with time, for better understanding purposes we can say the phase wire helps to flow electricity from source to load and the neutral wire helps to get returned the current flow from load to source. So for a complete electrical circuit, we need both phase and neutral wires.

## Phase Wire Color

The color of the phase wire or hot wire depends upon the country.

In most European countries,

Single Phase - Brown or Black

3 Phase L1 - Brown or Black

3 Phase L2 - Brown or Black

3 Phase L3 - Brown or Black

In the USA( United States),

Single Phase - Black or Red(2nd hot)

3 Phase L1 - Black

3 Phase L2 - Red

3 Phase L3 - Blue

In India,

Single Phase - Red

3 Phase L1 - Red

3 Phase L2 - Yellow

3 Phase L3 - Blue

## Live or Hot Wire in Single Phase System

We know that a single-phase system has a minimum of three wires a phase wire and a neutral wire. Sometimes it has one extra wire which is ground wire. The voltage between phase and neutral is called phase voltage. In a single-phase system, you will get only one voltage. For India, the phase voltage is 240V whereas in the USA it is 120V.

## Live or Hot Wire in Double Phase System

The double-phase system is also known as a two-phase system where two-phase wires are available. If there a neutral wire is also available then we will get two different voltages. For example, In India, we will get 440V between two phases and 240V between any one phase and neutral.

## Live or Hot Wire in Three-Phase System

The three-phase system contains three phase wires. The three-phase system that contains only three-phase wires is called a three-phase three-wire system but the three-phase system that contains three phase wires and one neutral wire is called a three-phase four-wire system. The voltage between any phase and the neutral is called phase voltage and the voltage between any two phases is called line voltage.

## Phase Wire Size

The size of a phase wire is very important and it is determined according to the system voltage, current flow, load, etc. Generally, the size of a phase and neutral wire for a particular load should be the same. Because they need to carry the same amount of current flow. When it is the fact of determining the size of the wire the current flow measurement in ampere is very important. Basically, the size of the wire is determined by the American Wire Gauge(AWG) Chart.