On Friday, November 22, 2013 4:37:03 AM UTC-5, Danny D'Amico wrote:
On Tue, 19 Nov 2013 18:03:14 +0100, nestork wrote:



I find the first diagram on this web page that was posted by SRN

helpful:



Here's a PNG of that diagram, for reference:

http://farm8.staticflickr.com/7292/1...4ba18de1_o.png



In the dryer thread, it was noted that most USA circuit breakers

are *not* arrayed in AB-AB-AB format; but in AA-BB-AA-BB format.



I'm not sure what that means though...

It's referring to where the two legs/phases show up in the panel.
But, I'm not sure what AB means either. You need to define what
the perspective is. Just saying AB is meaningless, because it could
mean A is on the left, B on the right, or it could mean A is above,
B is just below it. In any case, what you have, is the latter.
That is what is shown in your diagram.
Otherwise you would get zero from a double pole breaker instead
of 240V.

This web site won't let me post anything longer than about a dozen lines or so, so I'm going to break this post up into multiple posts...

Correct. That's a requirement of the electrical code, but why that is, I can't say that I fully understand. All of the neutral wires connect to the neutral buss in the main panel, and that neutral buss gets connected to ground, whether it be a plumbing pipe or a ground rod pounded into the ground outside your house.

If you look at an electrical panel, you will find the fuses or breakers in two vertical columns. Years ago, when people had fuse boxes, the fuses would be numbered 1, 2, 3, 4, etc. They also number the slots in breaker panels, but the numbering system is a bit different in that you have two breaker positions for each number. So, if you look at your breaker panel, you should see that there is both an upper and a lower position for #1, #2, #3, #4, etc.

The reason for having two breakers for every designated number is that it makes it easier to know whether you're connecting wires to the same, or different, voltage sources. I'll explain that in the next post...

So, if you have the kind of panel that's shown in the diagram above, every SECOND breaker on each column in the panel will be connected to the same voltage source. So, if you want to install the wiring to a new 240 volt arc welder, you know that you can put the double breaker to that welder ANYWHERE on the panel and the two sides of the breaker will be connected to opposite voltage sources to give you 240 VAC power.

However, in that post you said that most US breaker panels don't use the AB-AB-AB-AB format, but the AA-BB-AA-BB format instead. What that means is that instead of EVERY breaker position being connected to the opposite voltage source as the one above it or the one below it as it in AB-AB-AB-AB, you have every PAIR of breaker positions being connected to opposite voltage sources. So, BOTH breakers designated as #1 on the panel would be connected to the same voltage source, and ditto for both breaker positions designated as #2, and so on. So, in that case, if you wanted to do the wiring to install a new 240 volt arc welder, you would have to install the double breaker so that it straddled between two numbers. For example, you could install that double breaker at the #2 Lower and #4 Upper breaker locations, or at the #3 Lower and #5 Upper breaker locations so that each side of the double breaker was connected to a different voltage source.

People often assume that because there are two voltage sources and there are two columns of breakers in the panel, then the breakers on one side are powered by one voltage source and the breakers on the other are powered by the other voltage source, and this isn't true. That would present a safety risk because it wouldn't allow you to use double breakers to disconnect BOTH voltage sources from the appliance when you trip it's breaker.

Different panels are made differntly, and it's the buss bars inside the panel that determine what gets connected to what, but for safety reasons, it's important to connect 240 VAC appliances like stoves, dryers and central air conditioners to double breakers installed on the SAME SIDE of a panel. That way, you can't trip the power off to one voltage source without tripping it off to both voltage sources so that the appliance is safe to work on.

Not quite.
The power company sends those electrons out over three wires which are 120 degrees out of phase. Those wires travel great distances to the cities where the power is needed. A fourth ground wire also travels the same distance from the generating station to the city it services.

Once the wires get to the cities, then depending on the zoning in the city (whether, industrial, commercial or residential) the power from those wires is distributed differently. Industrial areas that need three phase power for their big three phase electric motors will be serviced by all three wires. Commercial and Residential areas will only be serviced by one of the three wires. At each telephone pole distribution transformer there is a step down transformer with a center tap that converts the 7200 volts carried in the one of those wires down to two 120 VAC wires, each 180 degrees out of phase with each other, and a neutral wire coming off the center tap of the transformer, as shown in this diagram:

http://tinyurl.com/ly24tjo

The electrons do flow through the ground, but not all the way back to the generating station through the ground. Each telephone pole transformer has it's own ground wire that goes down the pole from the transformer and is wrapped around the bottom of the telephone pole under the ground. So, the electrons only flow from the grounding rod or grounded plumbing pipe outside your house to the nearest telephone pole with a distribution transformer. Thereafter they travel along copper wires back to the generating station.

Right.
In this diagram:
http://tinyurl.com/ly24tjo
...the primary coil in the distribution transformer is shown as being connected between the 7200 volt cable and ground. That little dohickey that looks like a three pronged rake is the electrical symbol for "Ground".

At least, this is how I understand things, and so far I haven't electocuted myself.

Hope this helps.

Danny D'Amico wrote :
On Mon, 18 Nov 2013 06:48:27 -0800, wrote:

The 6 vs three makes no sense.

Here are six distribution wires, by the way ...
http://farm8.staticflickr.com/7456/1...349dd5b6_o.gif

Notice each pair of your 6 wires is connected at the insulator so
although there are 6 WIRES ther are only 3 THREE conductors

Please before you demonstrate your ignorance and confuse people who
admit they dont know, go back to shcool. :-?

--
John G

Danny D'Amico was thinking very hard :
On Mon, 18 Nov 2013 18:09:29 +0100, nestork wrote:

This web site explains it fairly well:
http://tinyurl.com/y4syno6

That was interesting.
Notice the 7200V primary side of the transformer didn't look
grounded in the picture (but it must have been). Right?

Also, the ground (literally) was stated as being part of the
circuit (although I would have like them to complete the circuit
at your lamp, and then *back* to the power company (via the
ground).

If you had any understanding of electricity you could understand that
the GROUND is not part of the circuit.
It is there to keep all the parts of the system at the same reference
potential.

A 3 phase Delta system requires only 3 wires.
A 3 phase Wye system has 4 wires to allow connection to the center
point and one phase to get a lower voltage than that between any 2
phases but a symetrical 3 phase load of the correct voltage only needs
3 wires.

The ground is only for safety and is, by code, connected to the neutral
at each customer.

The USA system delivers only ONE 240 volt supply to houses and the
neutral is really only a centre tap of that to get 120 volts for small
appliances.

I know there are variations (too complicated to explain here) but the
overall principle remains.

The ground wire plays no part in a proper fault free system.
No current flows in around or thru the ground if all the conductors are
installed to code. :-Z

--
John G

John:

In here, we all learn from each other.

None of us knows everything, but all of us know some things.
We collectively share what we know so that we're all better off for it.
That's how we get along.

nestork pretended :
John G;3153423 Wrote:

Please before you demonstrate your ignorance and confuse people who
admit they dont know, go back to shcool.
John G

John:

In here, we all learn from each other.

None of us knows everything, but all of us know some things.
We collectively share what we know so that we're all better off for it.
That's how we get along.

Thats OK and I respect it But we do not need people who do not know
what they are talking about spreading rubbish.

Ask questions by all means but leave out talking about things unknown
as though you are the expert.

In this particular thread there has been so much ignorance portrayed as
fact I thought it needed some correction. :-?

--
John G

Constructive criticism is always welcome in here.

"Danny D'Amico" wrote in message ...
On Tue, 19 Nov 2013 18:03:14 +0100, nestork wrote:

I find the first diagram on this web page that was posted by SRN
helpful:

Here's a PNG of that diagram, for reference:
http://farm8.staticflickr.com/7292/1...4ba18de1_o.png

In the dryer thread, it was noted that most USA circuit breakers
are *not* arrayed in AB-AB-AB format; but in AA-BB-AA-BB format.

I'm not sure what that means though...


Your panel is ABABAB...AB from top to bottom, on both sides of
the breaker panel (left/right). The example given in your .png
showed AB....AB on the left, and BA....BA on the right. This is
a lay-out that makes zero sense and would require some goofy
bus work to accomplish. If you look at your breaker mounting
points you will notice that every other bus tab, from top to
bottom, is the same. So, the top two bus tabs, inline from left
to right are phase A. The next row down will be phase B, inline
from left to right. A 2-pole breaker will take up two spaces, top
to bottom and will give you both an A and a B phase. A 2-pole
breaker mounted to its right will pick up the same bus tabs as the
first breaker, but, of course, it will be to the right of the first
circuit breaker. Just look at the two breakers that currently
exist at the top of your panel. They are end to end with their
operators (handles) moving in opposite directions to achieve the
same action. Yet, the wiring is the same for both breaker, top
to bottom. Meaning that if you where to have black and red wires
denoting phasing, the black would go on A, and the red would go on
B. This is a universal construct in electrical work. Black is always
A, Red is always B, and if three phase, blue would be C. A three
phase Delta would replace the red with an orange, denoting the fact
that the system is Delta, and that the B phase to ground is a high
leg and is not 120v and is not to be used for 120v circuits.

Colors are important!

I worked in a 240 Delta panel once that was phase taped for a Wye
connection. Black, Red, Blue. I needed to move a single pole
breaker down one slot to install a 3 pole breaker. There was a
single pole breaker at the top of the panel, on that side, so this
put the breaker I had to move down onto the high leg. I did not
notice this and since my boss just said hurry up, get it done, and
lets get out of here, I did not check the voltage. Well, someone
went into the bathroom and the fart fan ran really fast for about
10 seconds before it went up in a puff of smoke and the incandescent
lamp was really bright, too. Until it blew up. Never take anything
for granted for when you do so, you or someone else might get hurt.

"Danny D'Amico" wrote in message ...
On Mon, 18 Nov 2013 06:48:27 -0800, wrote:

The 6 vs three makes no sense.

Here are six distribution wires, by the way ...
http://farm8.staticflickr.com/7456/1...349dd5b6_o.gif


It is called parallel conductors. Two smaller cables take the
place of one large cable. Cost less, and carries a higher current
since the cross section of the smaller conductors cools more readily
in open air than one large conductor would. Both ends terminate,
respectively, at a single point. There are rules for this, too, but
that is another topic.

Most generators have at least one set of parallel conductors inside,
and have, usually, three sets(or more) going to the distribution bus
of the power plant. Depends on voltage, of course, and not all
generators are the same, so there are differences.

wrote in message ...
On Friday, November 22, 2013 4:37:03 AM UTC-5, Danny D'Amico wrote:


I'm not sure what that means though...

It's referring to where the two legs/phases show up in the panel.
But, I'm not sure what AB means either. You need to define what
the perspective is. Just saying AB is meaningless, because it could
mean A is on the left, B on the right, or it could mean A is above,
B is just below it. In any case, what you have, is the latter.
That is what is shown in your diagram.
Otherwise you would get zero from a double pole breaker instead
of 240V.

This is correct. My issue with the example provided was that there
were an A phase and a B phase shown, inline, left to right. I have
yet to see a panel with this layout. Even with three phase panels,
the layout is A, B, C. Top to bottom, identical on both sides of
the panel. The only deviation that I have seen is when the bus
tabs are used for the main breaker input, and this only causes the
loss of two connection points in the panel. This is a very common
practice in MCC distribution panels. So, 22 circuits... :-)

"Nightcrawler®" wrote in message ...

wrote in message news:3e983326-6c10-4862-9abf-
This is correct. My issue with the example provided was that there
were an A phase and a B phase shown, inline, left to right. I have
yet to see a panel with this layout. Even with three phase panels,
the layout is A, B, C. Top to bottom, identical on both sides of
the panel. The only deviation that I have seen is when the bus
tabs are used for the main breaker input, and this only causes the
loss of two connection points in the panel. This is a very common
practice in MCC distribution panels. So, 22 circuits... :-)

I meant to state load center, not distribution panel. Might as well
quit before the brain keeps a fartin'.

On Friday, November 22, 2013 6:17:08 PM UTC-5, John G wrote:
Danny D'Amico was thinking very hard :

On Mon, 18 Nov 2013 18:09:29 +0100, nestork wrote:



This web site explains it fairly well:

http://tinyurl.com/y4syno6



That was interesting.

Notice the 7200V primary side of the transformer didn't look

grounded in the picture (but it must have been). Right?



Also, the ground (literally) was stated as being part of the

circuit (although I would have like them to complete the circuit

at your lamp, and then *back* to the power company (via the

ground).



If you had any understanding of electricity you could understand that

the GROUND is not part of the circuit.

It is there to keep all the parts of the system at the same reference

potential.



A 3 phase Delta system requires only 3 wires.

A 3 phase Wye system has 4 wires to allow connection to the center

point and one phase to get a lower voltage than that between any 2

phases but a symetrical 3 phase load of the correct voltage only needs

3 wires.



The ground is only for safety and is, by code, connected to the neutral

at each customer.



The USA system delivers only ONE 240 volt supply to houses and the

neutral is really only a centre tap of that to get 120 volts for small

appliances.



I know there are variations (too complicated to explain here) but the

overall principle remains.



The ground wire plays no part in a proper fault free system.

No current flows in around or thru the ground if all the conductors are

installed to code. :-Z



--

John G

I agree with 99% of the above, except the last sentence. You will
have some very small portion of the current flowing through the ground.
Take for example the simple case of the neutral and ground of a 240/120V
service being tied together at the house and at the transformer. Those
are two paths for current to flow, just like two resistors in parallel.
The vast majority of the current will flow in the neutral conductor because of
it's low resistance. Some small amount, however will flow in the ground path, with it's higher resistance.

So it's 2-phase?

From Professor Cardell's web page at

http://www.science.smith.edu/~jcarde...ecPwr_HSW.html

"There are two wires running out of the transformer and three wires running to the house.
The two from the transformer are insulated, and the third one is bare. The bare wire is the ground wire.
The two insulated wires each carry 120 volts, but they are 180 degrees out of phase so the difference between them is 240 volts."

What needs to happen in here is for people to realize that talk about three phase delta and wye circuits may be interesting, but it's noise in here. We DIY'ers recognize that there is three phase power available for equipment that uses it, but it's not something that we need to know about, interesting though it may be. And, while I appreciate the input from the professional electricians in here, we all know that our brains are excellent housekeepers and that what we don't use will soon be thrown out to make room for stuff we will use. Three phase power, and how to wire it is something my brain is just itching to throw out. It needs the space for stuff it will use, like how to fix a fridge or spread drywall joint compound smoother.

nestork has brought this to us :
What needs to happen in here is for people to realize that talk about
three phase delta and wye circuits may be interesting, but it's noise in
here. We DIY'ers recognize that there is three phase power available
for equipment that uses it, but it's not something that we need to know
about, interesting though it may be. And, while I appreciate the input
from the professional electricians in here, we all know that our brains
are excellent housekeepers and that what we don't use will soon be
thrown out to make room for stuff we will use. Three phase power, and
how to wire it is something my brain is just itching to throw out. It
needs the space for stuff it will use, like how to fix a fridge or
spread drywall joint compound smoother.

You are of course correct but lots of people who know very little or
just enough to confuse themselves keep dragging PHASE into discussions
about houshold electrics.
The normal houshold supply in the USA is ONE phase with a centre tap
grounded to produce 120 volts above ground and 120 volts below ground
or 240 volts between the ENDS :/

--
John G

On Saturday, November 23, 2013 5:37:59 PM UTC-5, John G wrote:
nestork has brought this to us :

What needs to happen in here is for people to realize that talk about

three phase delta and wye circuits may be interesting, but it's noise in

here. We DIY'ers recognize that there is three phase power available

for equipment that uses it, but it's not something that we need to know

about, interesting though it may be. And, while I appreciate the input

from the professional electricians in here, we all know that our brains

are excellent housekeepers and that what we don't use will soon be

thrown out to make room for stuff we will use. Three phase power, and

how to wire it is something my brain is just itching to throw out. It

needs the space for stuff it will use, like how to fix a fridge or

spread drywall joint compound smoother.



You are of course correct but lots of people who know very little or

just enough to confuse themselves keep dragging PHASE into discussions

about houshold electrics.

The normal houshold supply in the USA is ONE phase with a centre tap

grounded to produce 120 volts above ground and 120 volts below ground

or 240 volts between the ENDS :/



--

John G


I guess the IEEE and it's power engineer members must
be among those knowing very little or just enough to confuse,
because they clearly speak in terms of two phases being present.

From a paper presented at a recent IEEE power engineering conference:

http://ieeexplore.ieee.org/xpl/artic...number=4520128

"Distribution engineers have treated the standard "singlephase" distribution transformer connection as single phase because from the primary side of the transformer these connections are single phase and in the case of standard rural distribution single phase line to ground. However, with the advent of detailed circuit modeling we are beginning to see distribution modeling and analysis being accomplished past the transformer to the secondary. Which now brings into focus the reality that standard 120/240 secondary systems are not single phase line to ground systems, instead they are three wire systems with two phases and one ground wires. Further, the standard 120/240 secondary is different from the two phase primary system in that the secondary phases are separated by 180 degrees instead of three phases separated by 120 degrees. "


It could not be any more direct and to the point.

wrote on 24/11/2013 :
On Saturday, November 23, 2013 5:37:59 PM UTC-5, John G wrote:
nestork has brought this to us :

What needs to happen in here is for people to realize that talk about
three phase delta and wye circuits may be interesting, but it's noise in
here. We DIY'ers recognize that there is three phase power available
for equipment that uses it, but it's not something that we need to know
about, interesting though it may be. And, while I appreciate the input
from the professional electricians in here, we all know that our brains
are excellent housekeepers and that what we don't use will soon be
thrown out to make room for stuff we will use. Three phase power, and
how to wire it is something my brain is just itching to throw out. It
needs the space for stuff it will use, like how to fix a fridge or
spread drywall joint compound smoother.



You are of course correct but lots of people who know very little or

just enough to confuse themselves keep dragging PHASE into discussions

about houshold electrics.

The normal houshold supply in the USA is ONE phase with a centre tap

grounded to produce 120 volts above ground and 120 volts below ground

or 240 volts between the ENDS :/



--

John G


I guess the IEEE and it's power engineer members must
be among those knowing very little or just enough to confuse,
because they clearly speak in terms of two phases being present.

From a paper presented at a recent IEEE power engineering conference:

http://ieeexplore.ieee.org/xpl/artic...number=4520128

"Distribution engineers have treated the standard "singlephase" distribution
transformer connection as single phase because from the primary side of the
transformer these connections are single phase and in the case of standard
rural distribution single phase line to ground. However, with the advent of
detailed circuit modeling we are beginning to see distribution modeling and
analysis being accomplished past the transformer to the secondary. Which now
brings into focus the reality that standard 120/240 secondary systems are not
single phase line to ground systems, instead they are three wire systems with
two phases and one ground wires. Further, the standard 120/240 secondary is
different from the two phase primary system in that the secondary phases are
separated by 180 degrees instead of three phases separated by 120 degrees. "


It could not be any more direct and to the point.

Further, the standard 120/240 secondary is different from the two phase
primary system in that the secondary phases are separated by 180
degrees instead of three phases separated by 120 degrees.

What all of this means is that analysis software and methods must now
deal with an electrical system requiring a different set of algorithms
than those used to model and analyze the primary system. This paper
will describe the modeling and analysis of the SINGLE-PHASE center tap
transformer serving 120 Volt and 240 Volt SINGLE PHASE loads from a
three-wire secondary.

It is interesting that you snipped the last Paragraph which says SINGLE
PHASE twice.

How clear is that? :-?

--
John G

John, we all understand that, but since the two 120 VAC sine waves coming into the house are 180 degrees out of phase with each other, it's natural to think of it as two phase power. Maybe it's not, but thinking of it that way helps us understand our house's electrical panel and the wiring coming out of it, and that's really the goal for most DIY'ers.

On Fri, 22 Nov 2013 22:47:56 +0100, nestork wrote:

All of the neutral wires connect
to the neutral buss in the main panel, and that neutral buss gets
connected to ground, whether it be a plumbing pipe or a ground rod
pounded into the ground outside your house.

This "ground stake" is right below the panel, driven into the ground:
http://farm6.staticflickr.com/5490/1...d624356b_o.gif

On Sat, 23 Nov 2013 10:02:08 +1100, John G wrote:

Here are six distribution wires, by the way ...
http://farm8.staticflickr.com/7456/1...349dd5b6_o.gif

Notice each pair of your 6 wires is connected at the insulator so
although there are 6 WIRES ther are only 3 THREE conductors

Please before you demonstrate your ignorance and confuse people who
admit they dont know, go back to shcool. :-?

I *knew* they were all hot wires! You have to notice the smiley sign at
the end the sentence.

I've previously said that there is three phase (120 degrees out of phase)
transmission and distribution, so, it's clear that I knew they were hots.

I happened to go to lunch with friends in San Jose and I saw the 6 wires,
and I thought of this discussion, so I snapped a picture of the 6 wires,
to show the team.

I do agree with you wholeheartedly. The GROUND is the conductor back to
the power plant (theoretically anyway). Clearly the wires I snapped are
three phase wires, and clearly the six wires are all are hot.

The insulators were gorgeous but the distant picture cropped doesn't
show how beautifully they shone with iridescent greenishblue colors.

On Sat, 23 Nov 2013 14:40:59 +1100, John G wrote:

In this particular thread there has been so much ignorance portrayed as
fact I thought it needed some correction. :-?

Hi Nestork & John,

The problem is my fault. I was making a joke, but, even with the smiley,
nobody got the joke.

I always tell my grandkids that if nobody gets the joke, then it's the
fault of the jokester.

So, while the 6 wires did look pretty, we all know they were all hot
wires. I didn't think anyone would think otherwise, so, that's why
I snapped the picture and posted it.

It was just to point out that you *can* have six wires; but, they're
all hot in this case!

On 11/23/13 4:37 PM, John G wrote:

You are of course correct but lots of people who know very little or
just enough to confuse themselves keep dragging PHASE into discussions
about houshold electrics.
The normal houshold supply in the USA is ONE phase with a centre tap
grounded to produce 120 volts above ground and 120 volts below ground or
240 volts between the ENDS :/



Well, what we think of as single phase isn't. It's actually two
phase. Trader 4 posted a link to an IEEE paper in another thread.
He http://tinyurl.com/lpwq82z
I work with irrigation which mostly relies on three phase power. We
sometimes tap power off grain bin sites which many times have "single"
phase 240. We'll use a transformer to produce 480 and add a phase
converter for the third phase. The converter adds one phase to the two
already there to run three phase motors.
It never occurred to me to think of "single" phase as actually two
phase until Trader posted the link. It has to be or phase converters
wouldn't make our irrigation systems run.
Granted, none of this probably matters to Joe Homeowner wiring a
garage light or a stove.

On Sun, 24 Nov 2013 00:54:46 +0000, Danny D'Amico wrote:

The problem is my fault. I was making a joke, but, even with the smiley,
nobody got the joke.

I just found where I actually said the joke, and, well, it's pretty clear
to me that I was joking. Oh well. It's still my fault if nobody got it.

Here is the exact quote that was snipped out prior. Notice I first explained
that the ground is the return path for the three 120-degrees-out-of-phase hot
wires, and then I added the one sentence (with a smiley) that got me in trouble:

Apologies in advance for the top posting - but here is the post in toto:

On Fri, 22 Nov 2013 09:47:51 +0000, Danny D'Amico wrote:

I was always of the opinion that the ground was the second set of three wires.
That is, the power company grabs electrons from the ground, and then it sends
those electrons over three wires, 120 degrees out of phase, and then the
electrons return to the power company through the ground.

It's a huge loop. At least the way I understand it.

BTW, here are six wires, but they're not the same thing!
http://farm8.staticflickr.com/7456/1...349dd5b6_o.gif

On Saturday, November 23, 2013 7:34:33 PM UTC-5, John G wrote:
wrote on 24/11/2013 :

On Saturday, November 23, 2013 5:37:59 PM UTC-5, John G wrote:

nestork has brought this to us :



What needs to happen in here is for people to realize that talk about

three phase delta and wye circuits may be interesting, but it's noise in

here. We DIY'ers recognize that there is three phase power available

for equipment that uses it, but it's not something that we need to know

about, interesting though it may be. And, while I appreciate the input

from the professional electricians in here, we all know that our brains

are excellent housekeepers and that what we don't use will soon be

thrown out to make room for stuff we will use. Three phase power, and

how to wire it is something my brain is just itching to throw out. It

needs the space for stuff it will use, like how to fix a fridge or

spread drywall joint compound smoother.







You are of course correct but lots of people who know very little or



just enough to confuse themselves keep dragging PHASE into discussions



about houshold electrics.



The normal houshold supply in the USA is ONE phase with a centre tap



grounded to produce 120 volts above ground and 120 volts below ground



or 240 volts between the ENDS :/







--



John G





I guess the IEEE and it's power engineer members must

be among those knowing very little or just enough to confuse,

because they clearly speak in terms of two phases being present.



From a paper presented at a recent IEEE power engineering conference:



http://ieeexplore.ieee.org/xpl/artic...number=4520128



"Distribution engineers have treated the standard "singlephase" distribution

transformer connection as single phase because from the primary side of the

transformer these connections are single phase and in the case of standard

rural distribution single phase line to ground. However, with the advent of

detailed circuit modeling we are beginning to see distribution modeling and

analysis being accomplished past the transformer to the secondary. Which now

brings into focus the reality that standard 120/240 secondary systems are not

single phase line to ground systems, instead they are three wire systems with

two phases and one ground wires. Further, the standard 120/240 secondary is

different from the two phase primary system in that the secondary phases are

separated by 180 degrees instead of three phases separated by 120 degrees. "





It could not be any more direct and to the point.



Further, the standard 120/240 secondary is different from the two phase

primary system in that the secondary phases are separated by 180

degrees instead of three phases separated by 120 degrees.



What all of this means is that analysis software and methods must now

deal with an electrical system requiring a different set of algorithms

than those used to model and analyze the primary system. This paper

will describe the modeling and analysis of the SINGLE-PHASE center tap

transformer serving 120 Volt and 240 Volt SINGLE PHASE loads from a

three-wire secondary.



It is interesting that you snipped the last Paragraph which says SINGLE

PHASE twice.



How clear is that? :-?


It's not a paragraph, it's part of the same paragraph.
And the part you referring to says:

"This paper will describe the modeling and analysis of the single-phase center tap transformer serving 120 Volt and 240 Volt single-phase loads from a three-wire secondary."

The transformer is single phase on the primary side. The loads it drives are
single phase 120v and 240v loads. No one is saying anything different. How can you ignore the elephant in the room where the author immediately before
explicitly addresses the exact core of the issue:

"Which now brings into focus the reality that standard 120/240 secondary systems are not single phase line to ground systems, instead they are three wire systems with two phases and one ground wires. Further, the standard 120/240 secondary is different from the two phase primary system in that the secondary phases are separated by 180 degrees instead of three phases separated by 120 degrees. "

He explicitly says that TWO PHASES ARE PRESENT and they differ by 180 deg.
That from an IEEE engineer presenting a peer reviewed paper at a power
engineering conference.

Or an app note from an electrical eqpt manufacturer:

http://www.behlman.com/applications/AC%20basics.pdf


"The two legs, represented by Phase A and Phase B, are
180 deg apart.



Or this white paper from another electrical eqpt manufacturer:

http://www.samlexamerica.com/support...Circuit s.pdf

Note the reference to Phase A and Phase B in the foot note to
the diagram and that they are 180 deg apart. And that the diagram
is clearly labeled Phase A and Phase B.

Are all of them among the confused, who know very little?
I have a degree in Electrical Engineering. Other than this
disagreement, is anything I've posted in these two threads
incorrect? Good grief.

What exactly is your definition of phase? Because it's derived
from one primary phase, you can never have more than one phase?
In electrical engineering, science, math, the most basic meaning of
the word phase is to express the relationship
between two periodic waveforms. In this case, in a split-phase 240/120V
service you have two different waveforms, they are 180 deg out of phase with
each other and you can see it on an oscilloscope. It's every bit as real as
seeing 3 phase waveforms on a scope. The 3 phases are seperated by
120 deg, the split phases service is seperated by 180 deg. That is EXACTLY
what the IEEE engineer is saying.

On Sun, 24 Nov 2013 11:34:33 +1100, John G
wrote:

wrote on 24/11/2013 :
On Saturday, November 23, 2013 5:37:59 PM UTC-5, John G wrote:
nestork has brought this to us :

What needs to happen in here is for people to realize that talk about
three phase delta and wye circuits may be interesting, but it's noise in
here. We DIY'ers recognize that there is three phase power available
for equipment that uses it, but it's not something that we need to know
about, interesting though it may be. And, while I appreciate the input
from the professional electricians in here, we all know that our brains
are excellent housekeepers and that what we don't use will soon be
thrown out to make room for stuff we will use. Three phase power, and
how to wire it is something my brain is just itching to throw out. It
needs the space for stuff it will use, like how to fix a fridge or
spread drywall joint compound smoother.



You are of course correct but lots of people who know very little or

just enough to confuse themselves keep dragging PHASE into discussions

about houshold electrics.

The normal houshold supply in the USA is ONE phase with a centre tap

grounded to produce 120 volts above ground and 120 volts below ground

or 240 volts between the ENDS :/



--

John G


I guess the IEEE and it's power engineer members must
be among those knowing very little or just enough to confuse,
because they clearly speak in terms of two phases being present.

From a paper presented at a recent IEEE power engineering conference:

http://ieeexplore.ieee.org/xpl/artic...number=4520128

"Distribution engineers have treated the standard "singlephase" distribution
transformer connection as single phase because from the primary side of the
transformer these connections are single phase and in the case of standard
rural distribution single phase line to ground. However, with the advent of
detailed circuit modeling we are beginning to see distribution modeling and
analysis being accomplished past the transformer to the secondary. Which now
brings into focus the reality that standard 120/240 secondary systems are not
single phase line to ground systems, instead they are three wire systems with
two phases and one ground wires. Further, the standard 120/240 secondary is
different from the two phase primary system in that the secondary phases are
separated by 180 degrees instead of three phases separated by 120 degrees. "


It could not be any more direct and to the point.

Further, the standard 120/240 secondary is different from the two phase
primary system in that the secondary phases are separated by 180
degrees instead of three phases separated by 120 degrees.

What all of this means is that analysis software and methods must now
deal with an electrical system requiring a different set of algorithms
than those used to model and analyze the primary system. This paper
will describe the modeling and analysis of the SINGLE-PHASE center tap
transformer serving 120 Volt and 240 Volt SINGLE PHASE loads from a
three-wire secondary.

It is interesting that you snipped the last Paragraph which says SINGLE
PHASE twice.

How clear is that? :-?

Give it up. You'll never convince Trader of even the obvious. He got
his EE degree from Cracker Jax.

I don't think it really matters whether we're calling the 120 VAC lines coming into our house "single phase power" or two separate phases. Or, precisely what to call it certainly doesn't warrant the amount of time being spent arguing over what to call it.

What matters is that we understand how the wiring in our houses (including the electrical panel) works, and I don't think that part was ever in question.

On 11/23/2013 5:37 PM, John G wrote:
nestork has brought this to us :
And, while I appreciate the input
from the professional electricians in here, we all know that our brains
are excellent housekeepers and that what we don't use will soon be
thrown out to make room for stuff we will use. Three phase power, and
how to wire it is something my brain is just itching to throw out. It
needs the space for stuff it will use, like how to fix a fridge or
spread drywall joint compound smoother.

You are of course correct but lots of people who know very little or
just enough to confuse themselves keep dragging PHASE into discussions
about houshold electrics.
The normal houshold supply in the USA is ONE phase with a centre tap
grounded to produce 120 volts above ground and 120 volts below ground or
240 volts between the ENDS :/

Wish I could remember the details. And the people
on this list are glad that I can't. But, I remember
hearing one time, how the theologians of earlier
generations used to write commentaries on this or
that. Commentary on the parable of this or that.
One theologian wrote a summation of the gospel,
in such simple terms he figured it would be the
do all and end all, of writings. Shortly after
he published it, a lot of people wrote commen-
taries on his summary.

Nestork did excellent job of shutting down the
thread, and then someone has to get in one last
word. And, others will write commentaries on
Stormin Mormon and his religious take on the
matter. Sigh.

--
..
Christopher A. Young
Learn about Jesus
www.lds.org
..

On 11/23/2013 7:12 PM, wrote:
I guess the IEEE and it's power engineer members must
be among those knowing very little or just enough to confuse,
because they clearly speak in terms of two phases being present.

From a paper presented at a recent IEEE power engineering conference:

http://ieeexplore.ieee.org/xpl/artic...number=4520128

"Distribution engineers have treated the standard
"singlephase" distribution transformer connection as
single phase because from the primary side of the
transformer these connections are single phase and in
the case of standard rural distribution single phase
line to ground. However, with the advent of detailed
circuit modeling we are beginning to see distribution
modeling and analysis being accomplished past the
transformer to the secondary. Which now brings into
focus the reality that standard 120/240 secondary
systems are not single phase line to ground systems,
instead they are three wire systems with two phases
and one ground wires. Further, the standard 120/240
secondary is different from the two phase primary
system in that the secondary phases are separated by
180 degrees instead of three phases separated by
120 degrees."


It could not be any more direct and to the point.


Aristotle says that 4,126 angels can dance on the head
of a pin.

Confucious says that incoming power in the USA in the
twenty first century will be single phase.

Jesus said if thy brother offend thee, and strike
thee on the phase, turn the other cheek.

Billy Graham says he's getting old, but that does
not phase me very much.

--
..
Christopher A. Young
Learn about Jesus
www.lds.org
..

On Saturday, November 23, 2013 7:56:02 PM UTC-5, Dean Hoffman wrote:
On 11/23/13 4:37 PM, John G wrote:



You are of course correct but lots of people who know very little or

just enough to confuse themselves keep dragging PHASE into discussions

about houshold electrics.

The normal houshold supply in the USA is ONE phase with a centre tap

grounded to produce 120 volts above ground and 120 volts below ground or

240 volts between the ENDS :/







Well, what we think of as single phase isn't. It's actually two

phase. Trader 4 posted a link to an IEEE paper in another thread.

He http://tinyurl.com/lpwq82z

Thank you. Good to see someone looked at the link and realizes what it
says.

That link is from the highest credibility source
you could possibly get, but aaddresses the very core of the issue:

"Which now brings into focus the reality that standard 120/240 secondary systems are not single phase line to ground systems, instead they are three wire systems with two phases and one ground wires. Further, the standard 120/240 secondary is different from the two phase primary system in that the secondary phases are separated by 180 degrees instead of three phases separated by 120 degrees."

I supplied other links to references from electrical eqpt manufacturers that clearly show and describe 2 phases, 180 deg out of phase with each other as well:

http://www.behlman.com/applications/AC%20basics.pdf

http://www.samlexamerica.com/support...Circuit s.pdf

So far, the other side has no references.




I work with irrigation which mostly relies on three phase power. We

sometimes tap power off grain bin sites which many times have "single"

phase 240. We'll use a transformer to produce 480 and add a phase

converter for the third phase. The converter adds one phase to the two

already there to run three phase motors.

It never occurred to me to think of "single" phase as actually two

phase until Trader posted the link. It has to be or phase converters

wouldn't make our irrigation systems run.

Granted, none of this probably matters to Joe Homeowner wiring a

garage light or a stove.


I'm still waiting for the definition of the meaning
of phase from those that deny that the two hot legs on a split
phase 240/120V service are 180 deg out of phase with each other.
That is what started all this. They appear to be hung up on the
fact that it's derived from a single primary phase. How it's
derived doesn't change what you get, what you can see on a scope,
how it drives a load, etc.
You brought up an example of generating an additional phase via
a transformer. Earlier I brought up another, very common example
too, open delta three phase.

For most 3 phase loads, 3 transformers are used to step down
from the primaries. They have 3 transformers, one connected to
each of the 3 utility primary phases. So far, I think everyone
agrees with that. Three phases in, three phases out.
Now, for light 3 phase loads, to save the cost
of an additional transformer, by using a center tap transformer,
the utility can supply 3 PHASE POWER, using only two transformers,
connected to only TWO of the utility primaries. The utility calls
that 3 phase power. The customer calls it 3 phase, the 3 phase
motors run on it, you can see 3 phases on a scope. Yet it's derived
from only TWO of the utility primary phases. Two phases in,
three phases out. Following the arguments of those on the other side,
then that should only be called two phase power. Yet there it is,
3 phase.

On 11/24/2013 08:54 AM, wrote:
As usual, instead of addressing the 10 ft elephant in the room,
krw hurls insults. Here, again from a peer reviewed IEEE paper
delivered at a recent conference of power engineers:


http://ieeexplore.ieee.org/xpl/artic...number=4520128

FWIW, I believe that krw is an idiot, fool, ass, halfwit, dunce, dolt, ignoramus, cretin, moron, imbecile and a simpleton.

On Sun, 24 Nov 2013 11:11:35 -0500, someone
wrote:

On 11/24/2013 08:54 AM, wrote:
As usual, instead of addressing the 10 ft elephant in the room,
krw hurls insults. Here, again from a peer reviewed IEEE paper
delivered at a recent conference of power engineers:


http://ieeexplore.ieee.org/xpl/artic...number=4520128

FWIW, I believe that krw is an idiot, fool, ass, halfwit, dunce, dolt, ignoramus, cretin, moron, imbecile and a simpleton.


No, I'm no lefty, like you and Malformed.

On Sunday, November 24, 2013 1:05:43 AM UTC-5, nestork wrote:
I don't think it really matters whether we're calling the 120 VAC lines

coming into our house "single phase power" or two separate phases. Or,

precisely what to call it certainly doesn't warrant the amount of time

being spent arguing over what to call it.



It does warrant a response when you have some people here saying that
anyone that says the you have two legs, two phases, 180 deg
out of phase, "know very little or just enough to confuse themselves".
And the village idiot questioning my degree in electrical engineering.
I take offense to that. I've provided a link to an IEEE peer reviewed
paper presented at a conference of power engineers.

http://ieeexplore.ieee.org/xpl/artic...number=4520128

"Which now brings into focus the reality that standard 120/240 secondary systems are not single phase line to ground systems, instead they are three wire systems with two phases and one ground wires. Further, the standard 120/240 secondary is different from the two phase primary system in that the secondary phases are separated by 180 degrees instead of three phases separated by 120 degrees. "

That's from an unimpeachable source, the IEEE. I've also provided links to eqpt
manufacturers, etc.

The other side, nothing but flapping gums.




What matters is that we understand how the wiring in our houses

(including the electrical panel) works, and I don't think that part was

ever in question.


That is correct. But when you start baseless personal attacks and are
incapable of even defining the word "phase", then what do you expect?

Well, then I expect Krw will be in good company in here.

I've been called all of those things by people who's judgement I trust!

Truth is that too many people in here let their technical disagreements turn into insult hurling contests and that's why you see posts like the one I responded to showing up. None of us knows everything, and so people don't feel offended if you correct them in a constructive way on a technical point. But, you're never going to convince anyone that they're stupid, and so arguments that develop along those lines result in hard feelings that linger for months or even years. So, what's the point in engaging in those arguments? It's just a waste of time for all concerned.

On Fri, 22 Nov 2013 23:11:08 -0600, Nightcrawler® wrote:

The example given in your .png showed AB....AB on the left,
and BA....BA on the right. This is a lay-out that makes zero
sense and would require some goofy bus work to accomplish.

I wish whoever kept posting that PDF would have known that
and not posted it then, because that's what we were going on.

So, the top two bus tabs, inline from left to right are phase A.
The next row down will be phase B, inline from left to right.

Makes sense.

A 2-pole breaker will take up two spaces, top
to bottom and will give you both an A and a B phase.

I like that we can *see* that, given there are two hots coming
out of the 240V breaker, so, it *must* be phase A & B.
http://farm6.staticflickr.com/5484/1...a8b636fc_o.gif

Meaning that if you where to have black and red wires denoting
phasing, the black would go on A, and the red would go on B.

This is an interesting observation.

Black is always A, Red is always B

Ah. This is news to me. So, all reds, in the breaker panel, would
be B then. But, isn't this red wire on A?
http://farm4.staticflickr.com/3696/1...38f77b97_o.gif

Here's a further-out view of that same breaker:
http://farm4.staticflickr.com/3794/1...cfcb99fb_o.gif

Since the red is on top, isn't that phase A (and not phase B)?

On Fri, 22 Nov 2013 05:58:03 -0800, wrote:

It's referring to where the two legs/phases show up in the panel.
But, I'm not sure what AB means either. You need to define what
the perspective is.

I'm going to make a stab at *guessing* what A & B are in my
main breaker panel.

Is this correct?
http://farm8.staticflickr.com/7294/1...3c991e33_o.png