In typical residential wiring it is the white wire. If you look in the electrical panel behind the panel you'll see all white wire are "bussed" together and the black "hot" wires are attached to breakers. The bare "Ground" wires are also all bussed together. The White and bare wires are typically bonded together in the main electric panel.
If you have a volt meter and you wanted to check for neutral without taking off an outlet cover you could ground one lead and then touch the other lead to each side of a receptacle and if you get 120V that is the hot side and zero is the neutral.
Danger - if you are removing electric panel covers and exposing the internals of the electric box there is a danger of getting electrocuted.
Neutral missing protection in a single-phase energy meter detects the absence of the neutral wire in the electrical circuit. When the neutral wire is missing, it can result in overvoltage on the load side. The energy meter typically shuts off to prevent damage to the connected equipment in such a situation.
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.
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.
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.
When one phase is missing in a 3-phase load, the load will experience an imbalance which can lead to overheating and potential damage to the equipment. The motor may run slower or produce less power, and the efficiency of the system will decrease. It is important to address the missing phase quickly to prevent further damage.
A three phase system will have 3 phase branch circuits and no neutral.
Neutral missing protection in a single-phase energy meter detects the absence of the neutral wire in the electrical circuit. When the neutral wire is missing, it can result in overvoltage on the load side. The energy meter typically shuts off to prevent damage to the connected equipment in such a situation.
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 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.
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
A CT is a current transformer, used to measure current flow in a conductor. Neutral is power return, usually grounded at the distribution panel. A neutral CT, then, is a device that measures the current flow in the neutral conductor. In a three phase star system, each phase returns current to neutral, but the three phases cancel each other out, resulting in effectively zero current in neutral. The neutral CT is used to detect an imbalance in the system, perhaps caused by a ground fault or by some failure in one of the phase loads. In a single phase, single ended system, there is current on neutral, so the value of a neutral CT is not so great. If you also had a hot CT, you could compare and detect imbalance between hot and neutral, which would be an indication of a ground fault. (Actually, a ground fault current interrupting device, also called a GFCI, usually compares current in hot and neutral simultaneously, because both conductors are wound together as the sensing transformer primary - any perceived current is a ground fault.) In a single phase, double ended system, such as the 120/240 split phase system used in the US, a current CT could indicate ground fault or a system imbalance but, usually, imbalance might be a normal situation as various loads are turned on and off.
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.
A three phase delta system does not use a neutral in its operation.
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.
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.
A CT is a current transformer, used to measure current flow in a conductor. Neutral is power return, usually grounded at the distribution panel. A neutral CT, then, is a device that measures the current flow in the neutral conductor. In a three phase star system, each phase returns current to neutral, but the three phases cancel each other out, resulting in effectively zero current in neutral. The neutral CT is used to detect an imbalance in the system, perhaps caused by a ground fault or by some failure in one of the phase loads. In a single phase, single ended system, there is current on neutral, so the value of a neutral CT is not so great. If you also had a hot CT, you could compare and detect imbalance between hot and neutral, which would be an indication of a ground fault. (Actually, a ground fault current interrupting device, also called a GFCI, usually compares current in hot and neutral simultaneously, because both conductors are wound together as the sensing transformer primary - any perceived current is a ground fault.) In a single phase, double ended system, such as the 120/240 split phase system used in the US, a current CT could indicate ground fault or a system imbalance but, usually, imbalance might be a normal situation as various loads are turned on and off.
Yes, you can reduce the neutral in a three phase system. you must figure the unbalanced current the neutral will carry and also make allowances for any harmonics that may be present.