In North America, the neutral wire is usually white; hot wires will be red or black; ground wires will be green. But it is not always the same; if you are working with three-phase power, or in applications where you have a lot of different wires, color codes can get lost.
In USA, Canada and other countries using a similar 60 Hz system:
In Europe and other world areas using a similar 50 Hz system:
The current carried by the neutral of a three phase four wire system is the un balanced current. If the three phase system was completely balanced on all three phases there would be no need for a neutral, eg a three phase motor. This neutral current will be less that the phase current so a reduction in the neutral size is allowed.
The limit or range of the neutral current in an unbalanced three phase system is the third harmonic in single phase non-linear load current is the major contributor to neutral current.
In a balanced three-phase system, the current in the neutral wire should ideally be minimal as the three phase conductors carry equal and opposite currents that cancel out in the neutral wire. However, if the loads are unbalanced, the neutral wire may have higher current due to the uneven distribution of power among the phases. This can happen when loads on each phase are different or when single-phase loads are connected between a phase and neutral, leading to increased neutral current.
If the motor is operated from a three phase three wire distribution system the motor will not need a neutral wire.
A smaller neutral wire in a three phase system can be used because it does not carry the full line current. It carries the unbalanced current of all three leg loads. This is one reason that three phase loads on a distribution panel should be equalized as much as possible to reduce the current on the neutral.
A delta-connected system is described as being a three-phase, three-wire, system, and doesn't have a neutral. But a balanced star (wye) connected load (e.g. a three-phase induction motor) doesn't actually require a neutral.
The current carried by the neutral of a three phase four wire system is the un balanced current. If the three phase system was completely balanced on all three phases there would be no need for a neutral, eg a three phase motor. This neutral current will be less that the phase current so a reduction in the neutral size is allowed.
A three phase system will have 3 phase branch circuits and no neutral.
Line, phase, neutral are terms used to describe the conductors in a three-phase system. The three live wires are called 'lines', and less correctly, 'phases'. Neutral is used for the fourth wire which in a balanced system carries no current.
If all three legs of the system are balanced then zero amps will flow all the way up to 100 amps if only one leg of the three phase system is used. The neutral in a wye three phase system carries only the unbalanced current. This is why in services for a three phase four wire system you are allowed to reduce the size of the neutral conductor.
The limit or range of the neutral current in an unbalanced three phase system is the third harmonic in single phase non-linear load current is the major contributor to neutral current.
In a balanced three-phase system, the current in the neutral wire should ideally be minimal as the three phase conductors carry equal and opposite currents that cancel out in the neutral wire. However, if the loads are unbalanced, the neutral wire may have higher current due to the uneven distribution of power among the phases. This can happen when loads on each phase are different or when single-phase loads are connected between a phase and neutral, leading to increased neutral current.
Earthing point is where conductor is directly connected to ground and its potential is always zero. Neutral is a return path in single phase system and in three phase system Neutral point will have zero potential if all the loads are balanced in the system. In un balanced three phase system even neutral point will have some potential
Because a three-phase system needs half the amount of wire to transmit power compared to three single-phase systems. With a balanced three-phase system the three live wires are phased so that the sum of the currents is always zero, which means that if the three neutral wires are combined, the current in the neutral is zero. Therefore the original three neutral wires can be removed, leaving only the three live wires. In practice a neutral wire is still included in three-phase four-wire systems when the load is potentially unbalanced, as for example in neighbouring houses which use different phases of a three-phase system for their individual single-phase supplies.
TPN Load break switch: Is basically a main switch used in three phase system and know as Three pole neutral or Three phase neutral having four connectors for three phases and one neutral.
As far as I understand, you don't need neutral line for connecting appliances that is 3-phase compilant. You only need the neutral line to connect a single phase appliance, which you connect along with one of the three lines.
A three phase delta system does not use a neutral in its operation.