Estimating KWh electicity billing using clamp-on amp meter

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. 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

the Electric Utility Management Program until his retirement in 2002. He is currently a consultant for Milsoft Utility Solutions. He is also a partner in WH Power Consultants, Las Cruces, NM.

It is still single phase, it will always be single phase. Where you happen to be standing when you look at that sine wave may change but as soon as you hook up 2 sources derived from a single phase input, you end up with one sine wave when you look at it from end to end. Changing your view might make it look different but it is still one sine wave.

BTW you still have not shown me a panel manufacturer saying split phase. They may say split bus but that is a whole different thing, pretty much out of use when we stopped using fuses.

I am not sure what the professor is trying to "model" with his math but that does not change what he is looking at.

You can say anything you want, just be aware professions in the electrical trades will snicker when they hear you call 120/240 anything but single phase. Folks in the inspector community also shun the word phase to describe the ungrounded conductors in a single phase system because they deal with an electrical code that is adopted as law and in laws, words matter.

He said "No, professionals call it single-phase. Unless you want people to think you voted for Hillary, you should use the proper terminology." Punctuation matters too.

Note the period between "No" and the next sentence,

VIJAY SHARMA is not an electrician and he seems to live in India. I am not sure I think his "white paper" accurately reflects American nomenclature for circuits here. Just the fact that he calls "2 phase" a "180 degree system" seems to show he may not really understand what he is talking about all the time. "2 phase" has a 90 degree phase angle difference.

The second phase you are reporting is a fake, which doesn't surprise me.  There's a lot of fake news out there.

Imagine a secondary transformer winding with a continuously variable location tap. You attach an oscilloscope probe to the tap and attach the scope common to L1.

Starting with the tap at the beginning of L1, slowly slide the tap along the secondary winding and note the scope trace.  You will see the amplitude change but the phase angle will remain constant.

I repeat, no matter where you position the tap along the winding, the phase angle stays the same.  Single phase.

Stop reporting fake science!

The fact that the word "phase" applies to one system (that one with the phases 90 degrees apart) doesn't mean it doesn't apply to another.

Consider that you can only have one neutral.

Or do we even need a neutral?  Does a 3-phase delta system have a neutral?

snipped-for-privacy@aol.com posted for all of us...

s are, it would have 2 hot lines and one neutral. In this case if the loads are balanced the current in the neutral will be zero. With unbalanced load s the current in the neutral is the difference between the 2 hot lines. Bec ause the current in one is 180

current from the other. Best practice is to try to

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

Let's hope Oren will post his picture on how to do it!

OK. No more than one neutral. That includes the delta with no neutral.

Simply choosing to call ungrounded conductors "phases" does not make it so. This came from 3 phase where each ungrounded conductor does represent a phase. When you are in single phase, it doesn't. People are simply trying to rationalize that when you take a single phase 240v circuit and cut it in half, you now seem to have 2 phases. If I walk half way up a ramp, it may look like 2 ramps, one going up and one going down but it is still just one ramp. Even when you gang together 2 or more sources, in series, once they are connected, they are still just one, single phase system and when you look at it end to end, it will just be one sine wave.

Yes or no, depending on whether we ground it or not. That is one reason why the NFPA really resisted using the term neutral and prefers "grounded conductor". In a center tapped 240/120 delta, the grounded conductor is a neutral, handling the unbalanced load from the center tapped transformer but in corner grounded delta there is no more unbalanced current on the white wire than on any ungrounded conductor.

There is also ungrounded delta, used in some critical industrial applications because of it's fault tolerance and also in those high voltage transmission lines. The medium voltage distribution going down your street (13kv - 26kv) may be delta but it is more likely to be wye. If there is only one primary, it is certainly wye. This is typical wye distribution

The problem here is you can't give a definition of phase. It's funny that all the experts here can't define single phase, two phase, N phase power and then explain how two phase at 90 deg is two phase, while at

I've asked before, suppose you took two phase and made it 179 deg, would it still be two phase? How about at 181? And again, I'm not talking about how things are called from history, I'm talking about what's actually there and how it's analyzed, just like the power industry engineer, who's presentation I referred you to. The only way I see to rule out 180 from being two phase is to specifically do it by definition. But so far, I don't see any definitions anywhere.

I defined phase as in single, 2 or 3. You just chose to ignore it.

You found one obscure white paper from a guy who lives in a place that does not even use center tapped services and he said "split phase" so you think that is the proper term. In another thread we did talk about split phase motors but they are still operating on single phase.

Phase is one sine wave, measured from end to end of a source and it's relationship to the other phases. In the US we have 1, 2 (very rare) and 3. Center tapping those secondaries does not magically add another phase. Since 3 phase wye is tied at the center, I can certainly play with a scope and show you 6 distinct sine waves. (Phase to phase x3 and line to neutral x3) I suppose you might call that 6 phase but you would be wrong.

You gave a definition that is historical, not from an engineering perspective and you didn't define anything more than 3. You would think if it's so simple, someone could define it for N phases. And then you refuse to answer the obvious questions that even a student would ask a teacher. According to you, two phase was 90 deg over four wires. OK, so, if it was over 3 wires, using one shared neutral, would two phases still be present? Now I change the phase to 179 degrees or 181 degrees, are there still two phases? Yes? No?

Why then are there not two phases present when it;s 180? The answer of course is that there still are two phases, it just becomes a less interesting case.

Canada doesn't use center tapped? Maybe Clare can enlighten us, but I thought they did. At any rate, the company sells power conversion products into the USA and he did a lot more than just call it split phase, he went through an analyis of it and how there are two 180 deg phases present.

But more importantly, did you not see the presentation at a US power industry conference that I provided? It's right here in the good old USA and it's a detailed analysis of exactly what we're talking about by an IEEE Fellow with 40 years experience.

Here it is again:

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 engineering conference and it's published by the IEEE, he's a Life Member of the IEEE. He last worked for Milsoft Utility Solutions, that does consulting 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.

You can read it here as a Word document:

It's crystal clear that he agrees with my analysis, but go ahead feel free to disparage him as a homeowner idiot.

I agree with that.

You look at a system from end to end, not any small segment. This is a single phase system.

I don't know how Canadians talk and Clare is quick to point out they do not use the NEC. We are talking about accepted nomenclature for US based electrical professionals. They have a different name for non metallic cable too.

"Split Phase" is a type of motor, not an electrical distribution method.

Go ahead and look like an unqualified homeowner if you want but don't be shocked when electricians and inspectors start to just roll their eyes and ignore you..

I am out.

Inability to answer the simple relevant questions a student would ask a teacher noted.

The issue was you claimed the author of the white paper I cited lives in a country that doesn't use center tapped transformers to provide

And no, we're not talking just about accepted nomenclature, we're talking about how you analyze circuits and what's really there. I've said that from my very first post here.

And again, you just completely blew off the IEEE paper that I again provided you with a link to. A paper written by a power engineer with 40 years experience, presented at a power industry conference, published by the IEEE. A paper that directly addresses exactly what we're talking about.

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 finally, I'd note I've given you and any other professionals here the opportunity for several days now to give us your engineering definiton of N phase power. No one can. Funny, it should be easy. Let me do it for you:

N Phase Power - A power delivery system that uses N related voltage sources , that are periodic waveforms of the same frequency, differing only in phase.

That covers it all. From single phase to an unlimited number of phases. It's like the unified field theory being sought in physics, the holy grail, only this one we have a complete definition and it's simple.

Single phase - covered Two phase 90 - covered Two phase 179 - covered Two phase 181 - covered Three phase - covered Six phase - covered

Now, the only way the 240/120V service isn't two phase under that simple, straightforward definition is if you explicitly put something in there to rule it out. Science and engineering typically don't do that. We have definitions or laws that fits all cases. Now from a historical pers pective, from a "that's what it's always been called in the power industry perspective", it can be labeled whatever winds up being used, for whatever reasons. It's like calling what you blow your nose with Kleenex or tissues. It doesn't change the fact that it's a soft paper product made from trees.

And if you have a better definition of N phase power, I'd be happy to see it.

I answered the question several times. I just told you what electricians and inspectors call the service you have in your house. If you can't understand that and need some other rationalizations to explain what you have, go for it. I don't care anymore.

Can't accept a phrase applying to more than one thing? "Split phase" is where two phases are made from one (in other words, one is split into two). Whether it happens in a motor or in a transformer doesn't change the appropriateness of the phrase.

No, you have not answered the simple specific questions.

You say that what was called two phase power 100 years ago when it existed, was in fact two phases. You said it was over 4 wires. I accept that. So, here are the simple questions a student might ask a teacher:

If it were on 3 wires instead of 4, with a shared neutral, would there still be two phases there?

If yes, then how about if I change the phase angle to 179 degrees or

If yes, then why if I change it to 180, are there no longer two phases?

What did you think of my definition of N phase power?

The problem with that is you did not create another phase. If you walk half way up a ramp, did you suddenly make two ramps. After all isn't one going up and the other going down, from where you stand? That is all center tapping a single phase transformer is doing.

The problem with using one term for two things is it confuses a process where we try to make it simpler. Confusion can be dangerous where electricity is concerned. We try to be precise when we speak.

It is actually on 5 wires and there is a neutral there. Two phase does still exist in some archaic industrial equipment in the North east the last I heard.

How did you get 181 degrees? If it comes from a separate system, yes it would be 2 phase.

The problem is you did not change it to 180. You just sampled a different place on the same single phase wine wave.

There is 1, 2 or 3 phase power in the US distribution system. Nothing else. I do understand you could have circuits operating at any number of different phase relationships but that will be in the electronIC world, not US power distribution. It is a different culture with words that are used differently. (I have lived in both) That is why you can find very well credentialed people who do not speak "electrician". I bet they think a "city hub" is a bus station and a "hickey" is something you don't want to see on your daughter's neck. ;-)