What is phase and neutral

what is phase and neutral

What is the Difference Between Neutral, Ground and Earth?

Phase can be considered as positive and neutral can be considered as negative terminal of battery. Only difference is that in DC circuit current flows from positive to negative terminal but in AC circuit it flows in both directions. Phase acts as main supply line while neutral acts like a return path for the circuit to be completed. Neutral is return path for an AC circuit which is supposed to carry current in normal condition. This current may be because of many reasons, primarily because of phase current imbalance and some time because 3rd and 5th harmonics also.

The neutral is a special line that runs in the power plants from the so-called wye star of the transformer and passes further to the substation. The same neutral line is distributed to houses. Generally, the neutral serves as a balancing line for a three-phase system. Experts strive to achieve a unique load of consumer power. In order to clearly understand the phenomenon, we will take as an example a building, in which the same number of apartments is connected to one of the three phases.

However, unequal consumption in this case still remains. Nrutral all, people in every apartment use different how is limestone used to make cement mortar and concrete appliances at different times of day and night.

The other end of the high voltage wire is output to terminals under the name A, B and C. The connected ends together at the neutral point are connected to the ground loop in the substation. There is, also, a separation of the high voltage wire of zero resistance at:. The described scheme is applied in new buildings.

In the switchboard of the building, electricians are supplied with 3 phases, PE phaee, and with neutral wire. In most of the old apartment houses there are no PE conductors. The power supply system consists of 4 wires, called TN-C. This scheme is outdated and is considered unsafe. The earth wire in this case is performed individually at the building. Phases and neutrals from the voltage transformers are carried out to the living space by means of neutrall or overhead high-voltage wires, which further are connected to the front panel of the house.

From the front panel, electricians set up wires at the entrances and apartments. Electricity is supplied to consumers using wires connected to one of the three phases with a voltage of volts.

When neutral conductors are carried to every consumer of electricity, the unbalanced load on the network virtually disappears. For additional protection of the house, a protective wire or PE is required. In case of a short circuit, it removes current from the wiring site, which protects people from electric shock and property from a fire. In such a network, the load is evenly distributed, since on each floor of the multi-residential house building wiring takes place in stages. Such a system is reliable and optimal, but it also has its own faults as periodic problems occur.

Electricity shortages are most often associated with poor wire quality, as well as a poor quality of their how to draw paintball guns. The main task of the protective wire is to protect the phase conductors from a direct lightning strike. In addition, the protective wire ensures a sufficiently low zero impedance of the line, which contributes to the reliable operation of the what is phase and neutral system in case of short circuit conditions.

It whta achieves a galvanic connection between the grounding conductors and thus improves the grounding systems of all lines. The protective conductor for the purpose of protecting the conductors from a direct lightning strike can be made of steel ropes, but for other purposes it would be desirable to be made of a better conductive material such as aluminum clad steel. The qhat serves as a reference point in the electrical installation.

The neutral conductor, thus is a normally a current-carrying conductor. It has a whwt in load balancing. The ground is normally not a current-carrying conductor. The ground provides an electrical path to the ground, in case of fault occurrence in the circuit, or in case of a lightning strike. The neutral conductor is connected to a transformer in a wye connection system. From this point, the line is carried to the end — users. The neutral can be grounded connected with the ground conductor in a so-called TN-C system — common conductor acting as a protective and neutral wire.

In case there are separate wires the system is TN-S and is recommended. The grounding can be also carried from the transformer station, or can be executed a separate system for the building. Cite Emilija Angelovska. March 6, Leave a Response Cancel Reply Name required. Email required. Please note: comment moderation is enabled and may delay your comment. There is no need to resubmit your comment. Notify me of followup comments via e-mail.

Written by snd Emilija Angelovska. Print [1]Linsley, T. Print [2]Donnelly, E. User assumes all risk of use, damage, or injury. You agree that we have no liability for any damages.

What is Neutral? There is, also, a separation of the high voltage wire of zero resistance at: what is phase and neutral PE conductor yellow-green color ; working neutral blue. What is Ground? Difference Between Neutral and Ground Purpose of Neutral and Wbat The neutral serves as a reference point in the electrical how to make a big pennis. Execution for Neutral and Ground The neutral conductor is connected to a transformer in a wye connection system.

Neutral vs. Ground Summary of Neutral and Ground The neugral wire serves as a reference point, used for load balancing in the system. Can be grounded. The ground wire is a protective conductor, protecting humans and devices in case of fault occurrence or lightning strikes.

Author Recent Posts. Emilija Angelovska. Latest posts by Emilija Angelovska see all. Help us improve. Rate this post! Cancel Reply. References : [0]Stokes, G. Get New Comparisons in your inbox:. Follow Us.

Balancing of Phases in 3 Phase 4 Wire System

Neutral: Neutral is the return path for an AC circuit that carries current in normal condition. This current could be primarily because of the phase current imbalance. The magnitude of this current is a fraction of phase current or in a few cases even double of the phase currents. Earth. Jul 13,  · Since each phase is the same voltage be it at the shop or at the other place (all are P-P or P-P), why can't I just run 2 phases into an autotransformer and ditch the neutral issue altogether setting for the shop and at the other place. May 14,  · Also known as Edison system, divided or neutral phase with central intake. This is the most common residential service in North America. Line 1 to neutral and line 2 to neutral are used to power loads of volts of lighting and electrical outlets.

As the neutral point of an electrical supply system is often connected to earth ground , ground and neutral are closely related. Under certain conditions, a conductor used to connect to a system neutral is also used for grounding earthing of equipment and structures. Current carried on a grounding conductor can result in objectionable or dangerous voltages appearing on equipment enclosures , so the installation of grounding conductors and neutral conductors is carefully defined in electrical regulations.

Where a neutral conductor is used also to connect equipment enclosures to earth, care must be taken that the neutral conductor never rises to a high voltage with respect to local ground.

Ground or earth in a mains AC power electrical wiring system is a conductor that provides a low- impedance path to the earth to prevent hazardous voltages from appearing on equipment high voltage spikes. Under normal conditions, a grounding conductor does not carry current.

Grounding is also an integral path for home wiring because it causes circuit breakers to trip more quickly ie, GFI , which is safer. Adding new grounds requires a qualified electrician with knowledge particular to a power distribution region.

Neutral is a circuit conductor that normally completes the circuit back to the source. Neutral is usually connected to ground earth at the main electrical panel, street drop, or meter, and also at the final step-down transformer of the supply. That is for simple single panel installations; for multiple panels the situation is more complex. In a polyphase usually three-phase AC system , the neutral conductor is intended to have similar voltages to each of the other circuit conductors, but may carry very little current if the phases are balanced.

All neutral wires of the same earthed grounded electrical system should have the same electrical potential, because they are all connected through the system ground. Neutral conductors are usually insulated for the same voltage as the line conductors, with interesting exceptions. Neutral wires are usually connected at a neutral bus within panelboards or switchboards, and are "bonded" to earth ground at either the electrical service entrance, or at transformers within the system.

For electrical installations with split-phase three-wire single-phase service, the neutral point of the system is at the center-tap on the secondary side of the service transformer.

Other arrangements of polyphase transformers may result in no neutral point, and no neutral conductors. The IEC standard IEC codifies methods of installing neutral and ground conductors in a building, where these earthing systems are designated with letter symbols. The differences are that the conductors may be separate over their entire run from equipment to earth ground, or may be combined all or part of their length.

Different systems are used to minimize the voltage difference between neutral and local earth ground. Current flowing in a grounding conductor will produce a voltage drop along the conductor, and grounding systems seek to ensure this voltage does not reach unsafe levels.

In the TN-S system, separate neutral and protective earth conductors are installed between the equipment and the source of supply generator or electric utility transformer.

Normal circuit currents flow only in the neutral, and the protective earth conductor bonds all equipment cases to earth to intercept any leakage current due to insulation failure. The neutral conductor is connected to earth at the building point of supply, but no common path to ground exists for circuit current and the protective conductor.

In the TN-C system, a common conductor provides both the neutral and protective grounding. The neutral conductor is connected to earth ground at the point of supply, and equipment cases are connected to the neutral.

The danger exists that a broken neutral connection will allow all the equipment cases to rise to a dangerous voltage if any leakage or insulation fault exists in any equipment. This can be mitigated with special cables but the cost is then higher. In the TN-C-S system, each piece of electrical equipment has both a protective ground connection to its case, and a neutral connection.

These are all brought back to some common point in the building system, and a common connection is then made from that point back to the source of supply and to the earth. In a TT system, no lengthy common protective ground conductor is used, instead each article of electrical equipment or building distribution system has its own connection to earth ground. Stray voltages created in grounding earthing conductors by currents flowing in the supply utility neutral conductors can be troublesome.

For example, special measures may be required in barns used for milking dairy cattle. Very small voltages, not usually perceptible to humans, may cause low milk yield, or even mastitis inflammation of the udder. Connecting the neutral to the equipment case provides some protection against faults, but may produce a dangerous voltage on the case if the neutral connection is broken.

Combined neutral and ground conductors are commonly used in electricity supply companies ' wiring and occasionally for fixed wiring in buildings and for some specialist applications where there is little alternative, such as railways and trams. Since normal circuit currents in the neutral conductor can lead to objectionable or dangerous differences between local earth potential and the neutral, and to protect against neutral breakages, special precautions such as frequent rodding down to earth multiple ground rod connections , use of cables where the combined neutral and earth completely surrounds the phase conductor s , and thicker than normal equipotential bonding must be considered to ensure the system is safe.

In the United States, the cases of some kitchen stoves ranges, ovens , cook tops , clothes dryers and other specifically listed appliances were grounded through their neutral wires as a measure to conserve copper from copper cables during World War II.

This practice was removed from the NEC in the edition, but existing installations called "old work" may still allow the cases of such listed appliances to be connected to the neutral conductor for grounding. Canada did not adopt this system and instead during this time and into the present uses separate neutral and ground wires. This practice arose from the three-wire system used to supply both volt and volt loads.

Because these listed appliances often have components that use either , or both and volts, there is often some current on the neutral wire. This differs from the protective grounding wire, which only carries current under fault conditions. Using the neutral conductor for grounding the equipment enclosure was considered safe since the devices were permanently wired to the supply and so the neutral was unlikely to be broken without also breaking both supply conductors.

Also, the unbalanced current due to lamps and small motors in the appliances was small compared to the rating of the conductors and therefore unlikely to cause a large voltage drop in the neutral conductor. In North American and European practice, small portable equipment connected by a cord set is permitted under certain conditions to have merely two conductors in the attachment plug.

The small cords to lamps, etc. Portable appliances never use the neutral conductor for case grounding, and often feature " double-insulated " construction. In places where the design of the plug and socket cannot ensure that a system neutral conductor is connected to particular terminals of the device "unpolarized" plugs , portable appliances must be designed on the assumption that either pole of each circuit may reach full main voltage with respect to the ground.

There are special provisions in the NEC for so-called technical equipment, mainly professional grade audio and video equipment supplied by so-called "balanced" volt circuits. The center tap of a transformer is connected to ground, and the equipment is supplied by two line wires each 60 volts to ground and volts between line conductors.

The center tap is not distributed to the equipment and no neutral conductor is used. These cases generally use a grounding conductor which is separated from the safety grounding conductor specifically for the purposes of noise and "hum" reduction.

Another specialized distribution system was formerly specified in patient care areas of hospitals. An isolated power system was furnished, from a special isolation transformer, with the intention of minimizing any leakage current that could pass through equipment directly connected to a patient for example, an electrocardiograph for monitoring the heart.

The neutral of the circuit was not connected to ground. The leakage current was due to the distributed capacitance of the wiring and capacitance of the supply transformer. A shared neutral is a connection in which a plurality of circuits use the same neutral connection. This is also known as a common neutral , and the circuits and neutral together are sometimes referred to as an Edison circuit.

In a three-phase circuit, a neutral is shared between all three phases. Commonly the system neutral is connected to the star point on the feeding transformer. This is the reason that the secondary side of most three-phase distribution transformers is wye- or star-wound. Three-phase transformers and their associated neutrals are usually found in industrial distribution environments. A system could be made entirely ungrounded. In this case a fault between one phase and ground would not cause any significant current.

In fact, this is not a good scheme. Commonly the neutral is grounded earthed through a bond between the neutral bar and the earth bar. It is common on larger systems to monitor any current flowing through the neutral-to-earth link and use this as the basis for neutral fault protection. The connection between neutral and earth allows any phase-to-earth fault to develop enough current flow to "trip" the circuit overcurrent protection device. In some jurisdictions, calculations are required to ensure the fault loop impedance is low enough so that fault current will trip the protection In Australia, this is referred to in AS Fault loop impedance calculation.

This may limit the length of a branch circuit. In the case of two phases sharing one neutral, the worst-case current draw is one side has zero load and the other has full load, or when both sides have full load.

In a three-phase linear circuit with three identical resistive or reactive loads, the neutral carries no current. The neutral carries current if the loads on each phase are not identical. In some jurisdictions, the neutral is allowed to be reduced in size if no unbalanced current flow is expected.

If the neutral is smaller than the phase conductors, it can be overloaded if a large unbalanced load occurs. Triplen harmonic currents odd multiples of the third harmonic are additive, resulting in more current in the shared neutral conductor than in any of the phase conductors.

In the absolute worst case, the current in the shared neutral conductor can be triple that in each phase conductor. Some jurisdictions prohibit the use of shared neutral conductors when feeding single-phase loads from a three-phase source; others require that the neutral conductor be substantially larger than the phase conductors. It is good practice to use four-pole circuit breakers as opposed to the standard three-pole where the fourth pole is the neutral phase, and is hence protected against overcurrent on the neutral conductor.

In split-phase wiring, for example a duplex receptacle in a North American kitchen, devices may be connected with a cable that has three conductors, in addition to ground. The three conductors are usually coloured red, black, and white.

The white serves as a common neutral, while the red and black each feed, separately, the top and bottom hot sides of the receptacle. Typically such receptacles are supplied from two circuit breakers in which the handles of two poles are tied together for a common trip. If two large appliances are used at once, current passes through both and the neutral only carries the difference in current.

The advantage is that only three wires are required to serve these loads, instead of four. If one kitchen appliance overloads the circuit, the other side of the duplex receptacle will be shut off as well.

This is called a multiwire branch circuit. Common trip is required when the connected load uses more than one phase simultaneously. The common trip prevents overloading of the shared neutral if one device draws more than rated current. A ground connection that is missing or of inadequate capacity may not provide the protective functions as intended during a fault in the connected equipment.

Extra connections between ground and circuit neutral may result in circulating current in the ground path, stray current introduced in the earth or in a structure, and stray voltage. Signal circuits that rely on a ground connection will not function or will have erratic function if the ground connection is missing. From Wikipedia, the free encyclopedia.

For uses of the term "grounding" or "earth" in electricity but not in the context of mains wiring, see ground electricity. Main article: Earthing system. Main article: Split-phase electric power. Categories : Electrical safety Electrical wiring Power engineering Electric power distribution. Hidden categories: All articles with unsourced statements Articles with unsourced statements from November Articles with unsourced statements from July

More articles in this category:
<- What year was asbestos banned in building materials - What are the names of all the moon phases->

4 thoughts on “What is phase and neutral

Add a comment

Your email will not be published. Required fields are marked*