Neutral and its Balanced load

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ronaldrc

Senior Member
Location
Tennessee
Neutral and its Balanced load

Hi, I see the neutral or the grounded conductor current flow as always being referred to
as the unbalanced current.


I think the term unbalanced load is confusing to those who have never studied simple
basic electrical circuits and do not have good understanding of them.

I 'm talking about voltages aiding and apposing each other in a circuit. The Buck Boost
transformer takes advantage of these effects.

An example would be to take three 1.5 Volt flash light batteries in series in the correct
polarity and it would equal 4.5 volts. 1.5 + 1.5 +1.5=4.5 volts

Now reverse the polarity of any one battery of the three and you create an opposing
voltage of 1.5 volts and now you will have a voltage of 1.5 volts. 1.5 +1.5=3 volts
3-1.5=1.5 volts



I understand that tapping the center of a transformer winding such as the
120/240 volt Edison system we use in our residential single phase, not two phase we
create a conductor on which the current will be completely nullified if the load from line
#1 to the neutral and line #2 to the neutral are exactly equal. And these voltages are of
opposite polarity of each other in the neutral conductor, and not out of phase.

I think when students are referred to the unbalanced current they should know that the
neutral or grounded circuit conductor and one of the lines if wired as a two wire circuit,
are just that a simple two wire circuit.

Thanks :)
 

mivey

Senior Member
ronaldrc said:
Neutral and its Balanced load

Hi, I see the neutral or the grounded conductor current flow as always being referred to
as the unbalanced current.


I think the term unbalanced load is confusing to those who have never studied simple
basic electrical circuits and do not have good understanding of them.

I 'm talking about voltages aiding and apposing each other in a circuit. The Buck Boost
transformer takes advantage of these effects.

An example would be to take three 1.5 Volt flash light batteries in series in the correct
polarity and it would equal 4.5 volts. 1.5 + 1.5 +1.5=4.5 volts

Now reverse the polarity of any one battery of the three and you create an opposing
voltage of 1.5 volts and now you will have a voltage of 1.5 volts. 1.5 +1.5=3 volts
3-1.5=1.5 volts


I understand that tapping the center of a transformer winding such as the
120/240 volt Edison system we use in our residential single phase, not two phase we
create a conductor on which the current will be completely nullified if the load from line
#1 to the neutral and line #2 to the neutral are exactly equal. And these voltages are of
opposite polarity of each other in the neutral conductor, and not out of phase.

I think when students are referred to the unbalanced current they should know that the
neutral or grounded circuit conductor and one of the lines if wired as a two wire circuit,
are just that a simple two wire circuit.

Thanks :)
I don't recall that the neutral current has always been referred to as the unbalanced current in a 2-wire circuit.

I do think it is important that they understand the neutral is a current carrying conductor just like the line conductor, but the neutral just happens to be tied to ground at some point.
 

ronaldrc

Senior Member
Location
Tennessee
mivey said:
I don't recall that the neutral current has always been referred to as the unbalanced current in a 2-wire circuit.

I do think it is important that they understand the neutral is a current carrying conductor just like the line conductor, but the neutral just happens to be tied to ground at some point.


Is that the reason you pointed the fact that the neutral is a current carrying conductor in this thread ?
http://forums.mikeholt.com/showthread.php?t=101435
 

mivey

Senior Member
ronaldrc said:
Is that the reason you pointed the fact that the neutral is a current carrying conductor in this thread ?
http://forums.mikeholt.com/showthread.php?t=101435
Partially. That thread had to do with voltage drop and the point was that out in the circuit, it will have a voltage that differs from ground.

If we are addressing those unfamiliar with basic electric circuits, they might think of the neutral as a ground. This can be dangerous as they think that the neutral is somehow safer to mess with. It is a current carrying conductor and can hurt you also, even if it is only carrying the unbalanced load.
 
This topic is a good way to express a lot about the "neutral/grounded" conductor.

For the novice and improperly trained, this is where theory, experience and some common sense all come together for a thorough understanding of what can be a fairly complex concept.
Which will bring some to a time consideration as all things are not learned/comprehended at one sitting.
 

ronaldrc

Senior Member
Location
Tennessee
This is a very important subject.

If I were an apprent. in maybe the first few weeks of school and followed this forum and its postings, I could easily believe there is no current on the neutral circuits of a two wire circuit taken off of a #12 muti wire circuit.

I mean look at some of the questions about the unbalanced current or load.

Does that make any sense?
 

tallguy

Senior Member
ronaldrc said:
This is a very important subject.

If I were an apprent. in maybe the first few weeks of school and followed this forum and its postings, I could easily believe there is no current on the neutral circuits of a two wire circuit taken off of a #12 muti wire circuit.

I mean look at some of the questions about the unbalanced current or load.

Does that make any sense?
Doesn't make sense to me (FWIW)... Why would someone think that?? If I'm understanding what you're saying, you're saying that someone would think that a MWBC was balanced. Why would they think that?
 

iwire

Moderator
Staff member
Location
Massachusetts
ronaldrc said:
there is no current on the neutral circuits of a two wire circuit taken off of a #12 muti wire circuit.

In my opinion the two wire circuit has no neutral, it has only grounded conductor.
 

ronaldrc

Senior Member
Location
Tennessee
tallguy said:
Doesn't make sense to me (FWIW)... Why would someone think that?? If I'm understanding what you're saying, you're saying that someone would think that a MWBC was balanced. Why would they think that?


The reason you don't understand this is because you have forgotten were you came from and how much knowledge you have gained through the years or even months if you understand how the balanced neutral works.

The theory of how electricity flows is not common sense and we should not forget that.

Or it wasn't common sense to me ,but maybe that was just me? :)
 

tallguy

Senior Member
ronaldrc said:
The reason you don't understand this is because you have forgotten were you came from and how much knowledge you have gained through the years or even months if you understand how the balanced neutral works.

The theory of how electricity flows is not common sense and we should not forget that.

Or it wasn't common sense to me ,but maybe that was just me? :)
Two points:

1) You're giving me too much credit. I don't know that much.

2) It may not be common sense, but once it is explained clearly, it's simple. If the ungrounded conductors are drawing different amps, they don't balance out. One doesn't have to understand why exactly, in order to grasp the ramifications of the principal.
 

tallguy

Senior Member
iwire said:
In my opinion the two wire circuit has no neutral, it has only grounded conductor.
That's the way I've always heard it as well... but the term "neutral" is synonymous with "white wire" in the common vernacular.
 

ronaldrc

Senior Member
Location
Tennessee
Tall Guy

I know you understand.But not because it is simple but because you are hungry for the knowledge and if not already will be a fine Electrician.

Bob

You really surprise me with that answer.Technically you are right
On a two wire circuit taken from a multi. wire circuit from the tap on to the light or
whatever of the two wire circuit it would not function anymore as a neutral.

It would only be a grounded conductor for 120 volts and would have a load current the
same as the ungrounded hot or black wire. How many new apprentice would know that?

If you where supervising this apprentice and where working on a light on a circuit
describe above with two number 12/2s in it and he ask you what the white wires where
your answer would probably be one is a neutral and one is a hot feed to the light switch.

It is just habit of always calling the white wire even in a 12/2 feed a neutral and I have
found that practice wide spread. :)
 

iwire

Moderator
Staff member
Location
Massachusetts
tallguy said:
but the term "neutral" is synonymous with "white wire" in the common vernacular.

I agree, along with 'hot' and 'ground', heck I use those terms in the field.

But IMO the first thing a student has to learn is the proper words.

To me a 'neutral' always carries the unbalanced current from two or more other conductors.
 

ronaldrc

Senior Member
Location
Tennessee
Bob

You miss quoted me I did not say there would be no current on the grounded conductor of a two wire circuit. I said a fresh apprentice might think that.

If this same apprentice measured this feed from the panel he might get a very low amp. reading on the neutral and this would have to be confusing. :)
 

Smart $

Esteemed Member
Location
Ohio
iwire said:
I agree, along with 'hot' and 'ground', heck I use those terms in the field.

But IMO the first thing a student has to learn is the proper words.

To me a 'neutral' always carries the unbalanced current from two or more other conductors.
Yes... but a neutral conductor refers to its system connection and purpose, not its absolute function in a two-wire circuit. Besides that, it can still be considered as carrying unbalanced load since there is no other load to balance the current.

Additionally, your concept seems to only consider the current on the conductor. What about voltage? A neutral conductor can be considered neutral in the sense that it is not a source of voltage and acts only as a voltage sink. This is why so many people get bit when working on circuits that should be deenergized!!!
 

tallguy

Senior Member
ronaldrc said:
Tall Guy

I know you understand.But not because it is simple but because you are hungry for the knowledge and if not already will be a fine Electrician.
Thank you.... you are very kind.

Alas, I won't be an electrician, as I recently resigned myself to the fact that it was just not financially feasible to pursue it. So, I am relegated to being a part-time volunteer "apprentice" from time to time when supervised by generous master electricians willing to donate their time to charitable projects. I try to make darn sure that I know enough to have confidence that my supervisors are competent as well...

Hopefully I've built up enough good will over the past year to maintain my standing here despite my ambiguous status...
 

ronaldrc

Senior Member
Location
Tennessee
Smart $ said:
Yes... but a neutral conductor refers to its system connection and purpose, not its absolute function in a two-wire circuit. Besides that, it can still be considered as carrying unbalanced load since there is no other load to balance the current.

Additionally, your concept seems to only consider the current on the conductor. What about voltage? A neutral conductor can be considered neutral in the sense that it is not a source of voltage and acts only as a voltage sink. This is why so many people get bit when working on circuits that should be deenergized!!!


If the neutral is not a voltage source how are you going to get a 120 volts?
 
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