Estimating KWh electicity billing using clamp-on amp meter

From your discussion group "So I would put forward the argument that the secondary is a center tapped transformer providing 120v each side of the center(with center hard wired to "earth"and providing the "neutral connection") and 220v across the whole winding. This does NOT constitute a "2 phase" system"

Don't let electronIC engineers confuse the terminology used by electricAL professionals. We use specific terminology to avoid confusion and perhaps save lives. Homeowners and electronics geeks can call things whatever they want but they only sound stupid when they talk to the people who do this stuff for a living.

Trader thinks "SDS" is the predecessor of Antifa. ;-)

When there is already something called "2 phase" applying that term to a single phase circuit is silly. I suppose you will want to call 3 p center tap delta "4 phase".

trader_4 posted for all of us...

re, it would have 2 hot lines and one neutral. In this case if the loads ar e balanced the current in the neutral will be zero. With unbalanced loads t he current in the neutral is the difference between the 2 hot lines. Becaus e the current in one is 180 degrees out of phase with the other the current from one cancels out the current from the other. Best practice is to try t o keep the loads balanced as much as possible.

Exactly...

degrees out of phase with the other the current from one cancels out the current from the other. Best practice is to try to

I guess we are ready for the old NEMA 5-15 ground pin orientation argument again. ;-)

pot.  Since they're so common, would you provide a link to one at home depot.com or lowes.com?

haps the proper term should be dual phase or split phase. Does that work fo r you? I really didn't expect I'd be waking anyone up by responding to a 7 year old post.

Yes it does, it creates two voltage sources that are 180 deg out of phase with each other. Why didn't you address the example in that other forum? I take two single winding generators, connect them on a single shaft at the power station. One winding is 180 deg out of phase with the other, they share a common neutral. Now you have two windings, does that make it two phase?

Do you ever read what I post? From my first post:

We went through this round and round a few years ago. I was somewhere clos e to your position. I said something along the lines that there are in fact two phases present, 180 degrees apart. But that they are derived from one of the three phases coming down the street and commonly referred to as split-phase. But when you spit-something, what do you get? Two things. I wouldn't call it a two phase panel though, that's not the common term for it. But it is very common to refer to each of the hots as a phase.

So, I really don't understand the problem here.

And then we heard from someone who at least thinks he's a *professional*, Ed's Electric, saying:

"No, professionals call it single-phase. Unless you want people to think y ou voted for Hillary, you should use the proper terminology."

I provided links to Siemens, Square D, etc. where they call their panels us ed for split-phase service "single phase". Funny I didn't see you correcting that guy, but here you are all over me, when I agreed that I would CALL IT split-phase service, because that most accurately describes what it is. I've said I would not call it two phase service, because that is not the convention. But that doesn't change how you ANALYZE it or what's there. This is like arguing that you have to only describe what we commonly call tissues as Kleenex. Or maybe as "tissues", that you can't describe them as a very soft, thin paper product that;s made from trees and used to blow your nose. I'm sure there are industry specs, details that more accurately describe tissues too, if you look into it. So, we can't say that tissues are really that, you can only say Kleenex because that's what the most common used term is? It's exactly what the poster in that other forum said, it's a question of semantics.

If you define what the voltages you're looking at in that circuit, the polarity, V1 across bulb one, V2 across bulb two, V3 across four bulbs, etc, you could attach a scope and show the various waveforms. Some would be 1.2V, some would be 4.8V, some would have one polarity, some would have the other depending on how you defines the polarity of the measurement points and you could display them on a scope. You could do it for a class in electrical basics. Then ask the class to analyze the relationships of those waveforms on a test. If a student was asked about your two bulb example, to explain what he sees in the picture from the scope and he answered:

Both are 60 hz sinusoidal waveforms, both are 1.2V, one is 180 degrees out of phase with the other, is he wrong? Is that an incorrect answer?

And note I've asked others here to give their definition of single phase, two phase, three phase and N phase power. Tell us how split-phase isn't really two phase, using your definition. So far, no one has been able to do it.

s the proper term should be dual phase or split phase. Does that work for y ou?

think you voted for Hillary, you should use the proper terminology.

I guess you didn't look at the links I provided where Siemens, Square D and other manufacturers of panels call their split-phase panels "single phase". I guess there are no professionals there.....

t.  Since they're so common, would you provide a link to one at homede pot.com or lowes.com?

aps the proper term should be dual phase or split phase. Does that work for you?

o think you voted for Hillary, you should use the proper terminology.

er and easier, increasing application flexibility and reducing inventory re quirements. At the same time, they deliver obvious and significant advances in design, function and quality.

lication flexibility; and reduced inventory requirements

Do you ever read what I post before going at it?

"We went through this round and round a few years ago. I was somewhere clo se to your position. I said something along the lines that there are in fact two phases present, 180 degrees apart. But that they are derived from one of the three phases coming down the street and commonly referred to as split-phase. But when you spit-something, what do you get? Two things. I wouldn't call it a two phase panel though, that's not the common term for it. But it is very common to refer to each of the hots as a phase."

litude.  Only a Hillary voter would mistake it for two-phase.

se generators are built on a single shaft) so that you get two 120VAC outpu ts that are 180 degrees out of phase. Would it be reasonable to call this t wo-phase power?

etween the common and either of the other lines and 240VAC between the two lines. Would it still be reasonable to call this two-phase power?

h the wires coming to the house are from a center-tapped transformer?

I didn't say there were not others there arguing the other side. Funny thing though, none of these "professionals" are able to define what single phase, two phase, three phase, N phase power means.

Are you sure you want to now resort to disparag "No, professionals call it single-phase. Unless you want people to think y ou voted for Hillary, you should use the proper terminology."

You gave him a wink. I guess that was before you saw the links I provided to Siemens, Square D, that show they call their panels single phase. That;s what they call them in the product catalog, in the index, etc. Doh!

-phase generators are built on a single shaft) so that you get two 120VAC o utputs that are 180 degrees out of phase. Would it be reasonable to call th is two-phase power?

t of the transformer is single phase as well.  I don't have a two-phas e generator on my utility pole.

Do you ever read what I actually post? From my first post on the matter here:

We went through this round and round a few years ago. I was somewhere clos e to your position. I said something along the lines that there are in fact two phases present, 180 degrees apart. But that they are derived from one of the three phases coming down the street and commonly referred to as split-phase. But when you spit-something, what do you get? Two things. I wouldn't call it a two phase panel though, that's not the common term for it. But it is very common to refer to each of the hots as a phase.

Or respond to a direct question that goes to the core of the issue:

Give us your electrical engineering definition of one phase, two phase, three phase and N phase power and then explain why split phase doesn't meet the definition of two phase.

Whether you get 1 phase (and 2 different voltages) or 2 phases from a center-tapped transformer depends on what point you use for a reference. Using one end gives you 1 phase, using the center tap gives you 2. Normally, it's the center tap that's grounded.

I can't tell you in simple terms why a nectarine isn't a peach either but they are not the same. Did you see the term "split phase" in those panel manufacturer's descriptions? I didn't. They had single phase and 3 phase. They didn't say "2 phase" either since that is really a thing, having absolutely NOTHING to do with 120/240. I really don't care anymore. You can sound stupid if you want, your choice but 120/240 is single phase to the people who do this for a living. It is only homeowners and hacks who call it anything else.

I didn't see them say "split" anything. They just said what we have been saying. A 120/240v panel is single phase.

Maybe some people call the "hots" phases but not people who know what they are talking about (and that might even include some 1& 2 family "electricians") Those are "ungrounded conductors".

The term "split phase" already exists, it refers to a type of motor winding. The term "2 phase" also exists. It refers to a system with 2 separate phases, 90 degrees from each other using 4 ungrounded conductors and a center tapped neutral. The fact that you center tap a phase does not create more phases, it just establishes where the ground reference is. Like I asked, would you call 3 phase delta with a center tapped winding "4 phase". Is corner grounded delta suddenly single phase (or "split/2 phase") It would certainly look like it to the average untrained person. There are 2 ungrounded conductors and a white neutral with a 2 pole service disconnect.

Your reference to the panel descriptions confirm what we say. There are no "split phase" panels, nor are they calling any of them "2 phase". They sell single phase panels and 3 phase panels.

As for electronic engineers, they simply use different terminology. They look at things from a different perspective. You will also find the voltage drop charts they use are different too. It doesn't mean they use different copper or wire sizes. They just apply different conditions when they rate the wire. Electronics people generally make lousy electricians. I have lived in both worlds and there is a vast cultural divide between them,.

I have defined single phase to you several times but let's try it again. It is a system derived from a single secondary winding of a transformer. (or a single rotating field in a generator/alternator stator). The fact that you ground the center tap of that secondary does not change a thing as far as the number of phases in concerned. There is still one sine wave generated (a single phase) and that does not change no matter where you stand to look at it.

If a the transformer secondary had 2 equally spaced taps, would LymeBoi call it 3-phase?

I agree, that's a good point, but it is being used center tapped neutral for what we're discussing.

Simply because you look at a single phase from a different spot does not make it 2 phases. If I give you a sandwich and cut it in half you don't have 2 sandwiches.

amplitude.  Only a Hillary voter would mistake it for two-phase.

phase generators are built on a single shaft) so that you get two 120VAC ou tputs that are 180 degrees out of phase. Would it be reasonable to call thi s two-phase power?

C between the common and either of the other lines and 240VAC between the t wo lines. Would it still be reasonable to call this two-phase power?

hich the wires coming to the house are from a center-tapped transformer?

k you voted for Hillary, you should use the proper terminology."

Who;s the "we". Ed's Electric posted that no professional would ever call it single phase. And you appeared to agree with him, you gave him a wink.

Again, in my very first post, I said I would not call them two phase either. But what they are called and what is there, what you see, how you analyze it are not one and the same.

Here, I found the presentation I referred to. It was made by a power system engineeing professor with a career going back to the 60's. He consults on power system, the presentation was made at a power engineeri ng conference and it's published by the IEEE. He last worked for Milsoft Utility Solutions, that does work for power utilities. He doesn't sound like a stupid guy or a homeowner.

Abstract: Distribution engineers have treated the standard "singlephase" distribution transformer connection as single phase because from the primary side of th e transformer these connections are single phase and in the case of standar d 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. Whic h 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 s ystems with two phases and one ground wires. Further, the standard 120/240 secondary is different from the two phase primary system in that the second ary phases are separated by 180 degrees instead of three phases separated b y 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 algor ithms than those used to model and analyze the primary system. This paper w ill describe the modeling and analysis of the single-phase center tap trans former serving 120 Volt and 240 Volt single-phase loads from a three-wire s econdary.

W. H. Kersting Milsoft Utility Solutions, USA W. H. Kersting (SM'64, F'89, Life Fellow 2003) was born in Santa Fe, NM. He received the BSEE degree from New Mexico State University, Las Cruces, and the MSEE degree from Illinois Institute of Technology. He joined the facul ty at New Mexico State University in 1962 and served as Professor of Electr ical Engineering and Director of the Electric Utility Management Program un til his retirement in 2002. He is currently a consultant for Milsoft Utilit y Solutions. He is also a partner in WH Power Consultants, Las Cruces, NM.

And he's saying pretty much what I'm saying, that yes it's derived from a single phase, center tapped transformer, but to correctly analyze it, model it, you treat it as having two phases. Note, he didn't say to call it two phase power, neither did I.

So, if I create the generator example where I use two windings in the generator 180 out of phase on a single shaft, share a common neutral, that's not single phase because it has two secondary windings? I don't see the number of windings being the issue.

The fact that you ground the center tap of that secondary

I agree that there is only one sine wave generated. What I don't get and what you haven't explained is why if coming out of the generator you had two hots 90 deg out of phase, that's two phase. I asked, but never got answered from anyone here, supposed it's 170 deg instead? Is that still two phase? If it's 190 deg is it two phase? Why if it's 180 is it suddenly not? That's the problem. Science and engineering likes rules, laws, explanations that fit the general case. And 180 would just seem to me to be one case of all the possible two phase possibilities. And how exactly you generate it doesn't matter to the box it's entering or how you analyze it. You can see that in the MIT example two, they just used two ideal voltage sources, that in their case were 90 degrees out. But you could use the same model, same math to *analyze* 120 deg, or (oh no), 180 couldn't you?

I agree after looking more at those panel makers, that they do use the term single phase, but other power system component manufacturers also call it split-phase, including other divisions of the same power system component manufacturer, eg Siemens

But again, that's not what we're talking about. That is the historical case of what it once was. I think you will admit they didn't have to make it 90, suppose it was 100 or 70? Would that still be two phase? So, what's so special, so different that 180 suddenly can't be analyzed, looked at as consisting of two phases? Yes it's a trivial case, but if