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In a single phase system the neutral wire is the return path of the circuit and may be near ground potential, in multiphase systems it carries the unbalanced current.
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In a single phase system where only one "hot" wire supplies current to the load, the "neutral" wire completes the circuit and carries the current flowing from the load back to the power station.
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As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
Before you do any work yourself,
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
Wiki User
∙ 14y ago
Wiki User
∙ 11y agoElectrical power is transported across distribution wires to supply Transformers. The voltage of the distribution wires is significantly higher than either the 240V or 120V that you use in your home.
The supply transformers are designed with a "center tap", meaning that half of the 240 V is across one side of the output and half is on the other side with the center tap being the zero reference point.
The neutral wire in your home is connected to that center tap and should be a THEORETICAL zero voltage, but in real life things just don't work out that way.
Wiki User
∙ 11y agoCanada and US transformer connections
To best explain this, visualize the three primary line that you see on pole tops in industrial areas. The voltage between these three lines is about 12,460 volts. Eight feet below these top lines that is a single conductor. This conductor is grounded every three poles with ground rods and is used as a ground (neutral) on wye connections. When you see a pod of three transformers mounted together they are combined into a three phase system. From each of the three high voltage lines, the voltage goes through three separate fuses and down to a high voltage bushing in each of the transformers. Inside the transformer the voltage goes through a coil and exits the transformer through a second high voltage bushing. This bushing is tied into the grounded conductor (neutral) and then down to a grounding pad completing the circuit. This connection puts 7200 volts across the transformers primary coil (12460/1.73 = 7200. The secondary voltages of these transformers are determined by the customer that wants the three phase service. It could be 600,480 or 240 volts. Each single transformer has two output bushings. These bushings can be wired into either a delta or star configuration depending on what the customer ordered.
In a single phase service, the name is derived from just using one of the three primary lines that are used above. It is the same primary connection, but the secondary is a bit different. The output secondary coil has three bushings coming out of the transformer. On the two outside bushings is the working voltage (house connections 240 volts). The middle bushing is a center tap of the secondary coil. This gives a voltage of (bushing left to center 120 volts) and (bushing center to bushing right 120 volts) The center tap of this transformer is grounded and connected to the single grounded eight foot lower conductor. The single phase service neutral is established at this point. These three secondary points are connected by triplex to the homes weather head where another connection is made to the homes service distribution. This is classed as a 120/240 volt service.
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If you need 220v 3-phase power how many wires are required coming in from the transformer or power pole and what are the voltages or potential purposes of each wire load 110v load 220v neutral ground?
In 120/208V 3 phase system you have 5 wires: three hots, one neutral, and one ground. You have 208V between any two hots and 120V between any hot and neutral. The neutral is the same as in a single phase system. Clarification: Only 4 wires maximum come from the pole - 3 phases and a neutral, and then only if the transformers are on the pole. The ground is always locally derived from a ground rod(s) and/or cold water pipe ground. Most of the time, only 3 wires come in from the pole - the 3 phases in a Delta configuration (Delta has no neutral). The neutral is then derived from a local transformer connected in a Delta-Wye setup. The neutral is the center connection in the Wye. So, from the utility feeder to the transformer - 3 wires. From the transformer (wherever it is located) to the building service entrance panel - 4 wires. The ground is connected at the service entrance panel, and from there to the rest of the building you would have all 5 wires. Clear? In the US, 208/120 is a standardized mains voltage, but in some parts of the world, the phase-to-phase voltage is 220. In that case, the phase-to-neutral potential (in a 3-phase system) would be 127 Volts, not 120.
What are the examples of single and two phase system?
In its simplest form, a single-phase a.c. system comprises two conductors: a line ('hot') conductor and a neutral conductor. In North America, however, it is usual for a single-phase residential supply to have three conductors: the two 'hot' conductors are connected across opposite ends of a single-phase transformer winding, while the neutral conductor is connected to the centre (tap) of that winding. This provides a combination of 240 V and 120 V, and is known as a 'split phase' single-phase system.A two-phase a.c. system is very rare, these days, and you are unlikely to come across one. It is an archaic system that has long since been replaced by the three-phase system. Essentially, this system was provided by an a.c. generator whose armature windings were physically displaced from each other by 90 degrees, thus providing two phase voltages that are 90 electrical degrees apart. Usually, a two-phase system was a three-wire system, providing two line conductors and a neutral. The resulting line voltage (measured between the two lines) would then be 1.42 times either of the phase voltages (measured between one of the lines and the neutral).
Can you hook up a delta to delta transformer to be a delta to wye transformer?
The open Delta or V-Connection transformer is an improvement of the 1 three-phase transformer. The open Delta transformer can restore power in a Delta-Delta three-phase bank when one of the three single-phase transformers, which can be individually disconnected and replaced in case of failure, breaks down. The open Delta transformer then allows functionality to be restored, but at a reduced power of 57.7 of the original power.
What is the difference between single phase and three phase electrical power services?
Answer for USA, Canada and countries using similar 60Hz household electricity supplies This is a very simplified answer: Single-phase has two hot "legs". Each are 120 V. for a total of 240 V. A neutral wire (white in color) will give you 120 V. When straight 240V is needed, a neutral isn't necessary. 3-Phase has 3 hot legs for a total of 480V. This voltage is generally used for motors in industrial and commercial settings. This voltage can be "stepped down" via use of a step-down transformer. This converts 480V into 120/208/277. 120V is used for common appliances. 208V can be used for dryers and ranges (if they're rated for 208). 277V is used for lighting circuits (again, lighting must be rated for 277V). 3-phase is used in commercial and industrial, including schools. A neutral is needed for 120V and 277V and is generally gray.For more information see the answers to the Related Questions shown below.
Can a three phase be converted to single phase using transformers?
Yes if the oven does not have any 3-phase motor, and after conver, the current will be tripple on single phase conductors, so make sure conductor and circuit brakers can handle the current and within limit. A link can be found below to a related question that has more specifics.
What is normal house current three wire single double or three phase?
Normal house current is two-phase, 240V. What comes into the house is two hots and a neutral. From hot to hot you get 240V and from either hot to neutral is 120V. In the electrical trade there are only single phase and three phase systems. The reason it is called single phase is that the primary connection on the high voltage side is one leg of a three phase system. This 3 PH system is usually about 12500 volts. On the primary side of the transformer, the connection is between one phase of the three phase system and ground usually in the area of 12,500/1.73 = 7225 volts. The secondary side of this transformer is 240 volts with a grounded center tap. As stated above this is where the 240, 120 voltages come from.
What is the shape of a single phase transformer?
Transformers come in many shapes. Cylindrical, square, and rectangular are three of the main shapes of transformers.
How many volts come out of the transformer to go to the house?
There are 240 volts for a single phase service. <<>> A single phase transformer that feeds homes has three bushings. The two outside bushings are the working voltage (house connections 240 volts). The middle bushing is a center tap of the secondary coil. This gives a voltage of (bushing left to center 120 volts) and (bushing center to bushing right 120 volts) The center tap of this transformer is grounded and connected to the single grounded eight foot lower conductor if it is a pole transformer. The single phase service neutral is established at this point. These three secondary points are connected by triplex to the homes weather head where another connection is made to the homes service distribution. This is classed as a 120/240 volt service.
If you need 220v 3-phase power how many wires are required coming in from the transformer or power pole and what are the voltages or potential purposes of each wire load 110v load 220v neutral ground?
In 120/208V 3 phase system you have 5 wires: three hots, one neutral, and one ground. You have 208V between any two hots and 120V between any hot and neutral. The neutral is the same as in a single phase system. Clarification: Only 4 wires maximum come from the pole - 3 phases and a neutral, and then only if the transformers are on the pole. The ground is always locally derived from a ground rod(s) and/or cold water pipe ground. Most of the time, only 3 wires come in from the pole - the 3 phases in a Delta configuration (Delta has no neutral). The neutral is then derived from a local transformer connected in a Delta-Wye setup. The neutral is the center connection in the Wye. So, from the utility feeder to the transformer - 3 wires. From the transformer (wherever it is located) to the building service entrance panel - 4 wires. The ground is connected at the service entrance panel, and from there to the rest of the building you would have all 5 wires. Clear? In the US, 208/120 is a standardized mains voltage, but in some parts of the world, the phase-to-phase voltage is 220. In that case, the phase-to-neutral potential (in a 3-phase system) would be 127 Volts, not 120.
What are the examples of single and two phase system?
In its simplest form, a single-phase a.c. system comprises two conductors: a line ('hot') conductor and a neutral conductor. In North America, however, it is usual for a single-phase residential supply to have three conductors: the two 'hot' conductors are connected across opposite ends of a single-phase transformer winding, while the neutral conductor is connected to the centre (tap) of that winding. This provides a combination of 240 V and 120 V, and is known as a 'split phase' single-phase system.A two-phase a.c. system is very rare, these days, and you are unlikely to come across one. It is an archaic system that has long since been replaced by the three-phase system. Essentially, this system was provided by an a.c. generator whose armature windings were physically displaced from each other by 90 degrees, thus providing two phase voltages that are 90 electrical degrees apart. Usually, a two-phase system was a three-wire system, providing two line conductors and a neutral. The resulting line voltage (measured between the two lines) would then be 1.42 times either of the phase voltages (measured between one of the lines and the neutral).
How many wires come in from the weather head?
If single phase - 2 wire service > two wires If single phase - 3 wire service > three wires If three phase - 3 wire service > three wires If three phase - 4 wire service > four wires US residential service is usually single phase 3 wire service: Two hots and neutral.
Two phase supply to transformer in panels taking out single phase supply?
Your question is rather confusing, as you do not specify what you mean by 'panels'. Your reference to a 'two-phase' supply is also confusing because two-phase supplies are an archaic precursor to 'three-phase' supplies, and it's unlikely you'll come across any two-phase supplies anywhere these days!
Can you hook up a delta to delta transformer to be a delta to wye transformer?
The open Delta or V-Connection transformer is an improvement of the 1 three-phase transformer. The open Delta transformer can restore power in a Delta-Delta three-phase bank when one of the three single-phase transformers, which can be individually disconnected and replaced in case of failure, breaks down. The open Delta transformer then allows functionality to be restored, but at a reduced power of 57.7 of the original power.
Where does the neutral come from when turning 3 phase into single phase say in a street sub station?
In a split phase service, which is the standard for residences and very small businesses in the US, Canada, and some other areas, one transformer is connected to one phase of the three phase primary distribution mains. The secondary winding is centertapped, with the centertap grounded and called neutral. The other two phases are not involved at all. Do not call the hot legs of the service phases. They are not phases. They are opposite legs of only one phase. <<>> Canada and US transformer connections To best explain this, visualize the three primary line that you see on pole tops in industrial areas. The voltage between these three lines is about 12,460 volts. Eight feet below these top lines that is a single conductor. This conductor is grounded every three poles with ground rods and is used as a ground (neutral) on wye connections. When you see a pod of three transformers mounted together they are combined into a three phase system. From each of the three high voltage lines, the voltage goes through three separate fuses and down to a high voltage bushing in each of the transformers. Inside the transformer the voltage goes through a coil and exits the transformer through a second high voltage bushing. This bushing is tied into the grounded conductor (neutral) and then down to a grounding pad completing the circuit. This connection puts 7200 volts across the transformers primary coil (12460/1.73 = 7200. The secondary voltages of these transformers are determined by the customer that wants the three phase service. It could be 600,480 or 240 volts. Each single transformer has two output bushings. These bushings can be wired into either a delta or star configuration depending on what the customer ordered. In a single phase service, the name is derived from just using one of the three primary lines that are used above. It is the same primary connection, but the secondary is a bit different. The output secondary coil has three bushings coming out of the transformer. On the two outside bushings is the working voltage (house connections 240 volts). The middle bushing is a center tap of the secondary coil. This gives a voltage of (bushing left to center 120 volts) and (bushing center to bushing right 120 volts) The center tap of this transformer is grounded and connected to the single grounded eight foot lower conductor. The single phase service neutral is established at this point. These three secondary points are connected by triplex to the homes weather head where another connection is made to the homes service distribution. This is classed as a 120/240 volt service.
What is the difference between single phase and three phase electrical power services?
Answer for USA, Canada and countries using similar 60Hz household electricity supplies This is a very simplified answer: Single-phase has two hot "legs". Each are 120 V. for a total of 240 V. A neutral wire (white in color) will give you 120 V. When straight 240V is needed, a neutral isn't necessary. 3-Phase has 3 hot legs for a total of 480V. This voltage is generally used for motors in industrial and commercial settings. This voltage can be "stepped down" via use of a step-down transformer. This converts 480V into 120/208/277. 120V is used for common appliances. 208V can be used for dryers and ranges (if they're rated for 208). 277V is used for lighting circuits (again, lighting must be rated for 277V). 3-phase is used in commercial and industrial, including schools. A neutral is needed for 120V and 277V and is generally gray.For more information see the answers to the Related Questions shown below.
Can a three phase be converted to single phase using transformers?
Yes if the oven does not have any 3-phase motor, and after conver, the current will be tripple on single phase conductors, so make sure conductor and circuit brakers can handle the current and within limit. A link can be found below to a related question that has more specifics.
What is open delta in power system?
An open delta is a transformer configuration where only two single phase transformers can be used to serve three phase load. If you have phases A, B, C, an open delta would be having a transformer connected from A to B, and another one connected from B to C, but no transformer from C back to A. This works for balanced three phase loads, but can only be operated at 58% of the the transformer's rating. This connection is used sometimes to lower initial costs for a plant that is expected to grow in load. 2 transformers need to be bought, so you save on not buying the third until load reaches the point it is needed. It also comes in handy if transformers need to be serviced, and a plant cannot come completely off line. If it can reduce load to below 58% the transformer rating, then one transformer at a time can be removed from service and worked on.
