Yes, a neutral wire has to be the same size as the hot wire. The reason has to do with the load current returning through it. If the sizes are uneven, this can cause the circuit to malfunction.
Is the neutral wire size the same as the hot wire?
I thought that the wire size depends on the amperage that the current passes. However in a 3 conductor cable, the size of the neutral wire is the same as the hot wire; which puzzles me. If both hot wires carry 15A current, the neutral wire will carry 30A current. Show activity on this post.
Can the neutral wire carry more than the other line?
So as you can see, the neutral ( N) will never carry more than either line ( L ). At least not in a properly wired circuit. This is because of the nature of alternating current, and the properties of a split-phase system. Show activity on this post.
What is the size of the neutral wire in a 3-conductor?
However in a 3 conductor cable, the size of the neutral wire is the same as the hot wire; which puzzles me. If both hot wires carry 15A current, the neutral wire will carry 30A current. Show activity on this post. A simplified representation of a multi-wire branch circuit, would look something like this.
Why is there no neutral wire in a 240V circuit?
This is why a straight 240V circuit (which is a line-to-line circuit as opposed to a line-to-neutral) requires no neutral wire. It is a 100% balanced line-to-line circuit.
Can I use a smaller wire for neutral?
The neutral (grounded conductor) cannot be smaller than the required size of the GEC (per table 250.66) and is not required to be larger than the largest ungrounded conductor.
What size should a neutral wire be?
The size of the neutral conductor is at least equal to 16 mm2 in copper or 25 mm2 in aluminium.
Does the neutral wire need to be the same size as the power wire?
The dryer circuit neutral has to be able to carry the full imbalance of the load. Since that load is unknown because you are wiring a receptacle not a piece of equipment, then the neutral must be full sized.
Are neutral wires interchangeable?
So to review, the neutral and hot wires are actually interchangeable as far as electrical flow through the appliance, but in America, we “polarize” the plugs to differentiate between the neutral (connected to ground) and hot wires.
Why is neutral wire thin?
In a three phase system neutral wire is thinner. Because neutral will carry only leakage or unbalance current of three phase. Unbalance neutral current constitutes very small percentage of phase wire. So to reduce cost, size of neutral wire is reduced.
Why is the neutral wire thicker?
The neutral wire should be thicker than phase wire when no. of loads uses a common neutral. Generally, in house wiring purpose a common neutral wire is used for all loads, in this case, the neutral should be thicker because the neutral wire carrying more current than phase currents.
Why does the neutral wire not shock you?
Now, we know that neutral is always connected to the ground or earth. So when touching the neutral wire standing on the ground there is no voltage applied to our body, therefore no current flow through our body and we do not get the electric shock.
Can I downsize my ground wire?
The answer is no if you're looking for a simple answer. More complex answer - What everyone is trying to say in the comments is that you can size the wire according to Table 250.122 in the NEC. This table allows you to size the equipment grounding conductors according to the breaker size protecting the circuit.
What size neutral do I need for 100 amp service?
When it comes to the lines connecting master and secondary panels, where the line will carry as much as a full 100 amps, use a 2-gauge non-metallic sheathed electrical cable. The cable must contain one or two hot wires depending on your needs, one neutral wire, and one ground wire. Each wire should be 2-gauge in size.
What happens if you get live and neutral the wrong way round?
Because when it's the wrong way around, the device is energized (the internal wiring is at a voltage potential higher than 0). So if there's a fault somewhere, you could potentially become a path to ground. Also in some older appliances, the grounded (neutral) conductor was bonded to the chassis of the device.
What happens if you mix up live and neutral wires?
There would be a shock hazard, and some devices might not work correctly. Depending on where exactly the wires are flipped, ground fault detecting circuit breakers may become ineffective. All around, this is a bad idea.
What happens if you mix up hot and neutral wires?
This happens when the hot and neutral wires get flipped around at an outlet, or upstream from an outlet. Reversed polarity creates a potential shock hazard, but it's usually an easy repair. Any $5 electrical tester will alert you to this condition, assuming you have a properly grounded three-prong outlet.
How much current does a neutral wire carry?
If both hot wires carry 15A current, the neutral wire will carry 30A current. electrical lighting.
What does it mean when a neutral of a multi-wire branch circuit only carries the imbalance of the current?
When it is said that the current cancels each other out, it means that the neutral of a multi-wire branch circuit only carries the imbalance of the current between the two circuits of a properly wired MWBC.
What would happen if two hot wires were out of phase?
If the two hot wires were out of phase then no current at all would flow into a 240-volt motor when it is wired across the hots.
What is a 3 conductor cable?
3 conductor cable is usually used for one of two purposes: An additional/dedicated hot (i.e. feeding a switched light and an always-on receptacle), or a multi-wire branch circuit. In the case of a multi-wire branch circuit, the two hot legs come from different legs of your supply (+120V, -120V), so they actually cancel each other out when properly balanced.
Do breakers have to be on two different phases?
However, you must be sure that the breakers in the panel are on two different phases. Generally breakers that are adjacent to one another are on different phases but not always. Some panels have alternating phases at the top of the panel and some at the lower end adjacent breakers are the same phase.
Can a neutral carry more than one line?
So as you can see, the neutral ( N) will never carry more than either line ( L ). At least not in a properly wired circuit. This is because of the nature of alternating current, and the properties of a split-phase system.
Can 3 conductor cable be used for split circuits?
As others have said the 3 conductor cable could be used for feeding two circuits on split phases. Transformer on the pole (or in the ground) is used as shown in Tester101's diagrams. However, you must be sure that the breakers in the panel are on two different phases. Generally breakers that are adjacent to one another are on different phases but not always. Some panels have alternating phases at the top of the panel and some at the lower end adjacent breakers are the same phase. Also a dual breaker that fits in a single slot would not be on separate phases.
What is the cross section of a neutral conductor?
1. The cross section of the neutral conductor is at least 16mm2 for copper conductors and 25mm2 for aluminium conductors; 2. There is no high harmonic distortion of the load current. If there is high harmonic distortion (the harmonic content, THD, is greater than 10%), as for example in equipment with discharge lamps, ...
What is the size of a conductor in a single phase circuit?
in poly-phase and single-phase three-wire circuits, when the size of the line conductors is less than or equal to 16mm2 in copper, or 25mm2 in Aluminium.
Is there current in a neutral conductor?
In a balanced three phase systems, the current in the neutral conductor is theoretically zero. However in a practical electrical installation, this is not the case. In fact there is always some current flow in the neutral although small if the loads in the three phase are sufficiently balanced.
Why do wires make a loop?
The reason current flows in the loop from source to load is that the source forces the voltage and current back and forth in the wire. Thus, the load experiences the back and forth current and voltage as well, since the live and neutral wires form the loop.
How long does it take to recoup oversized wire?
I was able to show him that the relatively small increase in the cost of the “oversized” wire and conduit would be recouped in less than 3 months in reduced electic usage.
What is the only return leg for all the current in a circuit?
If they’re fed by two or more phase-identical hot wires, then they need to be large enough that their cross-sectional area is at least equal to the sums of the cross-sectional areas of those two hot wires; in this case, the hot wires all supply current to the one neutral wire , and that current is all in phase with itself. The neutral wire is the only “return leg” for all the current in this circuit.
Can you ground a neutral wire?
Of course that's not foolproof because you can't ground everywhere, and yet the neutral wire is carrying significant current, so everywhere you don't ground will have some at least some voltage according to Ohm's law. And in the case of an electrical fault just before a grounding point, the neutral line can become completely live. So you try to avoid relying on the neutral line, and you certainly never use it to keep the metallic case of an appliance safe. So you get pushed in the direction of a three-wire system where live is high voltage (positive or negative or AC) relative to ground, neutral is low voltage (but not low enough to count on due to the high current) and ground is for safety and never carries current in normal operation. A ground fault detector is a very useful safety device that checks that the amount of current supplied by the live wire exactly balances that returned through the neutral wire (so that the ground wire is truly current-free).
Is a 220/120 vac a neutral?
That said, that isn't alway true either, as there is the case of a 220/120 vac appliance, such as an electric stove/oven. The cord on those will have a smaller neutral. This is because the main load is single phase 220 vac, with 120 vac control circuits. The neutral is there for the return path for the control circuit only. Appliances have their own section of the code, and are not considered as “building wiring”.
Do you use the same size counductors in a wire?
In building wire, always use the same size counductors through the whole circuit.
Do you need the same size conductor on both sides of a load?
On a single phase circuit, you must (according to NEC) use the same size conductor on both sides of the load ..
Michael Bruss
field. Mostly, 2HP 220VAC single phase pumps will be run from the subpanel,
HUDDLE007
120V, 1 phase circuit out for your lights and tools. It's probally easier and
Greg Fretwell
240v with some 120v. They want you to use a number of 140% of the maximum
Mrichard
there is more than just one answer, which would be based on your situation.
Louis Bybee
Mrichard wrote: > > It's been a while since I've come across someone who can explain that > correctly. > You lookin for a job by any chance Louis?
Mrichard
Yes, that is wrong. But you cannot calculate a load to determine the size
Why is hot wire the same size as neutral wire?
Hotwire and neutral wire must always be the same size. Because they return the same amount of current load. For ground wire, the size can either be smaller or bigger sometimes.
How to tell if a house has a ground wire?
A way to tell if your home has ground wire is to check the prolongs. If you’ve three prolongs in your electrical outlet, there’s a ground wire. If there are two, the ground wire has not been utilized.
How does ground wire work?
Ground wire works as a defense system against unsteady electrical current. Normally under any circuit, the ground wire doesn’t carry any current.
What is ground wire?
Ground wire refers to the electrical connection with the earth. It works as a reservoir for the charge. What happens is that it opens a current conducting path to the ground. It acts independently unlike normal moving charge caring paths.
Why does my ground wire fail?
Answer: Ground wires failure happens due to ground fault. It is the accidental current passed to the ground wire. It may happen due to old worn-out wire, loose connection, or miswiring.
Why do wires burn?
Sometimes smaller wires can’t hold the excessive current flow. This results in the burning and melting of the wire.
Where is the ground wire on a service panel?
The ground wire is always attached to the neutral port of the service panel. Some households don’t have grounding systems in their electrical service. Most old household’s electrical systems don’t consist of ground wire connections.
