# Poco phasing.



## Majewski (Jan 8, 2016)

Flyingsod said:


> Is there a standard in your area?
> Where I lived and worked before there was none. It was a total crapshoot. ABC could be clockwise or counterclockwise comming into the building from poco.
> Now I’m in another area and my fellows here are thinking phasing is always the same from the poco.
> 
> ...


never assume anything is the same


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## 460 Delta (May 9, 2018)

It’s usually what you demand it to be. At my last job I changed a service from a private mine system to a POCO service. I needed ABC and they were wanting to hook it up CBA at the pad mount. I finally asked why can’t you change two elbows and give me ABC? A couple of them looked at each other and finally said, uhh, yeah we can, sure.


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## Flyingsod (Jul 11, 2013)

460 Delta said:


> It’s [Bold]usually[/Bold]what you demand it to be.


You live in a very different area from what I have experienced. 


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## cuba_pete (Dec 8, 2011)

It might just be easier to set rotation at the customer side of the service.


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## Flyingsod (Jul 11, 2013)

cuba_pete said:


> It might just be easier to set rotation at the customer side of the service.


For sure. And that’s what I’ve always had to do. 
One time the poco came and did a disconnect for me. When they hooked back up phase rotation was different. Luckily the customer only had a couple three phase motors. Getting poco back out woulda been hellish. 


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## Flyingsod (Jul 11, 2013)

Majewski said:


> never assume anything is the same


Sage words. 


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## 460 Delta (May 9, 2018)

Flyingsod said:


> You live in a very different area from what I have experienced.
> 
> How so?
> Sent from my iPhone using Tapatalk


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## Flyingsod (Jul 11, 2013)

Most of my experience with a poco is from one metropolis in the Midwest. You could absolutely not demand anything of them. If you tried your demands would be sent to committee to languish until you engineered a new fix that didn’t involve them. 

A helpful poco let alone one you could demand things of is just not in my set of experience. 


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## 460 Delta (May 9, 2018)

Flyingsod said:


> Most of my experience with a poco is from one metropolis in the Midwest. You could absolutely not demand anything of them. If you tried your demands would be sent to committee to languish until you engineered a new fix that didn’t involve them.
> 
> A helpful poco let alone one you could demand things of is just not in my set of experience.
> 
> ...


Maybe demand is the wrong word then, ask or better yet require would be better. The linemen are generally just regular guys like you and me and aren’t obstinate, but sometimes really don’t understand why a phase sequence reversal would be an issue. After I explained what I would have to do to fix the situation, and all they had to do, they understood and were just fine. 

Same guys crimped on 7, double hole terminals on my 3/0 wires I had roughed up in the xformer cabinet for me so I didn’t have to use my Roto-Crimp crimper and risk a hernia again.


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## Flyingsod (Jul 11, 2013)

Double post edit. Sorry


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## Flyingsod (Jul 11, 2013)

460 Delta said:


> Maybe demand is the wrong word then, ask or better yet require would be better. The linemen are generally just regular guys like you and me and aren’t obstinate, but sometimes really don’t understand why a phase sequence reversal would be an issue. After I explained what I would have to do to fix the situation, and all they had to do, they understood and were just fine.
> 
> Same guys crimped on 7, double hole terminals on my 3/0 wires I had roughed up in the xformer cabinet for me so I didn’t have to use my Roto-Crimp crimper and risk a hernia again.


So maybe not so different from you. The poco as an entity was a bureaucratic quagmire. Some of the workers were awesome though. One in particular would do whatever was necessary to get the power back on. Most others would just do their job but a fair percentage would find just about any excuse to deny the job and move on to the next. 


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## Jlarson (Jun 28, 2009)

I usually try not to confuse the line monkeys too much, I'm just happy they get all three phases hooked up, we'll put them were they need to be. Same with rentals, we always check and phase.


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## micromind (Aug 11, 2007)

Around here, if you ask for CW when you meet with the staking engineer, you'll get CW. 

Also, if they disconnect and reconnect, it'll be the same rotation. 

It's been a long time ago but I heard that they disconnected a line that ran about a dozen deep well turbine pumps and reconnected is reverse rotation. The motors didn't have ratchets so they spun the bowls off every pump and since they start with SCADA and are not supervised, they ran backward long enough to really wreck stuff........

They paid a ton of $$$ to fix it.


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## SWDweller (Dec 9, 2020)

There are a lot of electrical legends out there. I have heard that one before, and others that are similar. Nowadays I assume that they are cautionary tails for the inexperienced. I check everything usually 3 times. To easy to check and not have to have the conversation on "why"

I have never done deep pumps with out phase and rotation protection. Where I live and purchase Symcon is a very popular brand. There are other products out there that do the same operation.


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## ScooterMcGavin (Jan 24, 2011)

California’s largest utility has an ACB phase sequence. So we’re always backwards. LOL. Makes paralleling generators tricky since they’re almost always ABC. Guys hook up motors ABC/123 and wonder why they always get rotation wrong.


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## micromind (Aug 11, 2007)

SWDweller said:


> I have never done deep pumps with out phase and rotation protection. Where I live and purchase Symcon is a very popular brand. There are other products out there that do the same operation.


I agree, on the initial install. Usually, I will uncouple the pump from the motor then get the correct rotation.

In this case, the pumps were about 30 years old and ran fine until the PUCO swapped a couple of phases.


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## paulengr (Oct 8, 2017)

So how do you define "ABC" and "CBA"? It's not as easy as you think. Different relays from different manufacturers define it differently and that's the issue. Unlike say the right hand rule or defining current as flowing from positive to negative (even if it doesn't), there simply is no convention for phase rotation.









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The problem is this. Say I label each "hump" on a three phase chart with the phase that is connected to. So if I just read across the chart I will see either "ABCABCABC" or "CBACBACBA". But if it looks like say "ABCABCABC" then which phase will "rise first"? If we start with "A" phase then B leads A and C leads B, leading us to call this "CBA". There are many similar ways to define things and since there is no one true accepted way to do it, we have no agreement on what clockwise and counterclockwise mean. All that we can do is that we use a phasing meter whenever we have to connect lines coming from different directions together to make absolutely sure that they are phased correctly, and that we often have to swap a few leads around on a power meter.

If back when things were just getting established we had some kind of agreement, and that Edison and Tesla didn't hate each other, we might have had an agreed convention. But we didn't so we never will.


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## oldsparky52 (Feb 25, 2020)

paulengr said:


> , we have no agreement on what clockwise and counterclockwise mean.


This statement confuses me.


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## tmessner (Apr 1, 2013)

paulengr said:


> So how do you define "ABC" and "CBA"? It's not as easy as you think. Different relays from different manufacturers define it differently and that's the issue. Unlike say the right hand rule or defining current as flowing from positive to negative (even if it doesn't), there simply is no convention for phase rotation.
> 
> 
> 
> ...


Well said. I was wondering the same thing. Just because it is ABC in the transformer, who knows what is "A" back at the substation.


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## glen1971 (Oct 10, 2012)

We swapped out a transformer for a client and I set up a phase rotation meter in an empty cell. It was showing me "CBA" or counter clockwise. When we connected our secondary, I had Blue on T1, Black on T2, and Red on T3, which here would be CBA. We re-energized and the rotation meter was showing "ABC". Well crap... No big deal (to me), as the utility was still on site. I said drop the fuses, ground it and I'll move my 12 secondary leads. The "consultant", asked me how I terminated it, and said there's your problem - you switched "A" (red) and "B" (blue) to change rotation and it doesn't work like that. I replied with my usual WTF look after working 14 hours. After an hour him and a tech they had for testing were convinced they were right, even after I wrote it out "ABCABCABC" and "CBACBACBA". They left the MCC Room, and the client's plant electrician looked at me and said, you know you're right, right? I said yup, and thanks, but how does it make you feel that those 2 will tell you when I'm done my job? They finally wound up convincing the utility to switch 2, then come back the next day, so I could fix my "mistake". I kindly reminded them that if they switched AND I switched, we'd be right back to where we were at that moment.. shakin my head....


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## micromind (Aug 11, 2007)

oldsparky52 said:


> This statement confuses me.


Some phase rotation meters (like the one I have) are a miniature 3 Ø motor. The leads are black, red and blue. Black is labeled phase A, red is B and blue is C.

When connected, if the motor turns CW, it's called CW rotation. If it's CCW, then it's called CCW rotation.

Every phase rotation meter I've ever seen (maybe 20 or so) will give the same results. For example, if the PUCO labels their side of the switchgear CW, my meter will also read CW and any equipment that is rotation sensitive (like a phase failure relay) will be ok with CW but not with CCW.

CW rotation could also be defined as the voltage on phase A peaks then phase B then phase C then phase A again and so on.

There isn't a national standard for which phase is A, A is whatever you call it in your equipment.


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## paulengr (Oct 8, 2017)

oldsparky52 said:


> This statement confuses me.


Let’s put it this way.

Here is one way to define it:



https://electricala2z.com/wp-content/uploads/2018/08/Figure-1.png



If you have worked with phasor diagrams this should all be obvious. If not it might be confusing. So pay attention to the voltage chart on the left. We can see all three phases 120 degrees apart and they are in “ABC” order using those labels. Most people would call this “ABC”.

Now if we take just the A phase and plot the voltage on the X axis of a chart (horizontal line) positive voltages extend to the right, negative to the left. You can see “A” plotted on the phasor diagram to the right just this way. Now if we look at the Y axis on the right and we plot the B phase 120 degrees away, it will be at the 11 O’Clock position just as shown. Finally we get the C axis at the 7 O’Clock position. So this is counterclockwise. And reading things off we would call this “CBA”.

But if we start with the Y axis and plot the phasor diagram like hands on a clock we get B phase at 4 O’Clock and C phase at 8, and it’s clockwise. Thus it is “ABC”.


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## joe-nwt (Mar 28, 2019)

micromind said:


> A is whatever you call it in your equipment.


"A" was designated as such at the very first 3PH generator ever installed in North America and it is still "A" today. What you designate as "A" today matters not, as long as "B" And "C" follow in that order if you want ABC rotation at your equipment.


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## cuba_pete (Dec 8, 2011)

The physics tell us what is cw and ccw. Test equipment all use the same convention because, luckily, time only moves in one direction on our plane of existence. Now, if only all of the pocos and equipment manufacturers could agree on that one reality, it would make a sparky’s job easier. But, as a a result, we are more educated and technical and smart about something that makes plumbers and hacks look stupider.


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## ScooterMcGavin (Jan 24, 2011)

"A" is just your reference/base phase that's chosen to be considered the first. So even if it is the POCO's C phase, the other two phases will be judged based on what A is doing. So CBA, or BAC, is really just ACB. Just like BCA, or CAB is just ABC. All metering and relaying equipment I have ever worked with always considers A the reference phase and the other two phases are judged against that. It really doesn't matter unless you're trying to parallel equipment, because the phases need to be correct sequence and peak at the same time.


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## oldsparky52 (Feb 25, 2020)

micromind said:


> Some phase rotation meters (like the one I have) are a miniature 3 Ø motor. The leads are black, red and blue. Black is labeled phase A, red is B and blue is C.
> 
> When connected, if the motor turns CW, it's called CW rotation. If it's CCW, then it's called CCW rotation.
> 
> ...


Thanks, but I'm not sure that explains what Paul meant by "we have no agreement on what clockwise and counterclockwise mean. " 

The makers of the meters seem to have an agreement since you get the same readings between different meters. You also have an agreement based on motor rotation.


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## joe-nwt (Mar 28, 2019)

oldsparky52 said:


> Thanks, but I'm not sure that explains what Paul meant by "we have no agreement on what clockwise and counterclockwise mean. "
> 
> The makers of the meters seem to have an agreement since you get the same readings between different meters. You also have an agreement based on motor rotation.


None of those meters actually tells you which "A" phase is. All they tell you is whether the second and third phase you connect to are CW from the first.


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## oldsparky52 (Feb 25, 2020)

joe-nwt said:


> None of those meters actually tells you which "A" phase is. All they tell you is whether the second and third phase you connect to are CW from the first.


I always understood that. It was Paul's statement


> we have no agreement on what clockwise and counterclockwise mean.


 that I didn't understand.


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## joe-nwt (Mar 28, 2019)

Well I'm not sure what he meant by that either, he seems to have contradicted himself in his next post.

Maybe he will explain in more detail.


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## Flyingsod (Jul 11, 2013)

tmessner said:


> Well said. I was wondering the same thing. Just because it is ABC in the transformer, who knows what is "A" back at the substation.


That was my point in our in house discussion. Others seemed to believe it was a magically concrete definition. I’ve been in enough different places to know better though. 


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## JRaef (Mar 23, 2009)

Where I live in Northern California, PG&E is ACB rotation, which messes people up when they buy devices that insist on looking for ABC. 

During the recent wildfire events we had last summer, crews from all over the West were brought in to help restore power to damaged areas, One of them was apparently unaware of this (or forgot) and connected ABC. A business park in that area had everything run backward for a while when power was restored, it was a mess.


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## dogman (Apr 16, 2009)

I worked for a Electric coop for 34 yrs, we never worried about rotation on new service. A friend worked at a different coop, and they always did abc. I agree with the statement a lot of lineman don’t understand rotation.


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## Flyingsod (Jul 11, 2013)

JRaef said:


> Where I live in Northern California, PG&E is ACB rotation, which messes people up when they buy devices that insist on looking for ABC.
> 
> During the recent wildfire events we had last summer, crews from all over the West were brought in to help restore power to damaged areas, One of them was apparently unaware of this (or forgot) and connected ABC. A business park in that area had everything run backward for a while when power was restored, it was a mess.


Dixie didn’t get anything of mine but I was kicked out of the house for awhile by it. 

All the generators we have gotten recently needed to have the rotation reversed so it’s looking like they are indeed ABC clockwise. And as you stated pge is not. 


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## Flyingsod (Jul 11, 2013)

dogman said:


> I worked for a Electric coop for 34 yrs, we never worried about rotation on new service. A friend worked at a different coop, and they always did abc. I agree with the statement a lot of lineman don’t understand rotation.


Where I used to live the Poco kept their linemen ignorant of theory. They were taught procedure only and were not encouraged towards any ivory tower pursuits. 


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## GladMech (Sep 18, 2020)

The only thing I care about is what happens when I stick a Ty-Rap in the motor fan.


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## oldsparky52 (Feb 25, 2020)

Flyingsod said:


> Where I used to live the Poco kept their linemen ignorant of theory. They were taught procedure only and were not encouraged towards any ivory tower pursuits.
> 
> 
> Sent from my iPhone using Tapatalk


I understand concentrating on procedures. And I guess the lineman really doesn't need to understand theory just like I didn't when I first started pulling NM (yes, NM not NMB). The most complicated thing I did was wire a 3-way switch. 

Now, I figured a lineman would read about it on their own just to have an idea of what's going on. I do agree that most lineman I have met are light on theory.


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## JRaef (Mar 23, 2009)

Flyingsod said:


> Where I used to live the Poco kept their linemen ignorant of theory. They were taught procedure only and were not encouraged towards any ivory tower pursuits.
> 
> 
> Sent from my iPhone using Tapatalk


About 20 years ago, PG&E was sponsoring courses at a local JC on electrical relaying and protection. I was at that time getting involved in having to program a lot of protection relays that came in on equipment I was starting up, so I signed up. I attended the first few weeks, but I dropped it because they were designed to teach their Linemen how to become Protection Relay Technicians since they had a shortage of relay techs and too many linemen (in their eyes). The reason I dropped it is because they were not exhibiting any inclination to TEACH anything useful about protection theory etc., it was all just rote learning of steps to take to program THEIR specific protection relays based on a parameter sheet given to them by Engineering, or to troubleshoot a malfunctioning relay (which mostly involved swapping it out).


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## SWDweller (Dec 9, 2020)

I went to Pearl Harbor to commission a new 4000amp 480v SES for the Navy. We got the breakers done and the gear checked so we had them energize. Immediately we were the wrong rotation. I traced every thing back to the man hole where our responsibility ended. Rotation was still wrong. We had some sharp Captain who wanted us to remove the backs of the gear so he could see that the busing was not changed, IE straight through. He kept waving his hand near the powered buss when I finally pulled him out of the building. I told him that the utility people had made a mistake and they needed to correct the problem. We had followed the plans and specs to the letter. He refused to consider the concept. Then a Admiral showed up asked some questions and listened to me about how and why and where the problem was. He called the Captain and the contractor and low and behold they found the rolled MV cables. Problem solved. Me and the crew were invited to the show the next day. A sub from sea showed up connected all 4000 amps into the stern of the boat. They had a lot of brass good food, we stayed away from the drink, at work and all. I walked over to the front gang plank and looked at the two seamen chrome helmets, shoes you could see yourself in, M-15 and side arm. Walked away and the Admiral asked me if there was anything he could do. Sure a quick visit on board. No was the answer, I thought so. He asked why Navy dock and armed seamen protecting the gang plank means nuclear tools on board.
Admiral smiled. My security clearance from the DOE did not include ships.
Wish I could have seen the north shore that trip.


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## bill39 (Sep 4, 2009)

Here is my war story on matching up the utility rotation w/an existing hospital’s rotation. New MCC’s & service w/16 sets of paralleled 750 MCM’s in 4” conduits to utility’s new transformer.

We had matched up our phasing correctly to existing equipment but when utility hooked up the primary cables to transformer and energized it they had their rotation backwards. All of the wires (both primary & secondary) were too short to swap inside the transformer enclosure. I successfully argued/convinced them to swap A &C phases up on the pole to get the correct rotation. That was 40 years ago and it is still in service.


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## Southeast Power (Jan 18, 2009)

You have to feel our pain with Open Deltas. The POCO terminates their larger transformer on AB with the highleg on C. We have to switch B and C. guess what, yup, they give us CW and we have to turn it into CCW to satisfy our code.


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## Southeast Power (Jan 18, 2009)

SWDweller said:


> I went to Pearl Harbor to commission a new 4000amp 480v SES for the Navy. We got the breakers done and the gear checked so we had them energize. Immediately we were the wrong rotation. I traced every thing back to the man hole where our responsibility ended. Rotation was still wrong. We had some sharp Captain who wanted us to remove the backs of the gear so he could see that the busing was not changed, IE straight through. He kept waving his hand near the powered buss when I finally pulled him out of the building. I told him that the utility people had made a mistake and they needed to correct the problem. We had followed the plans and specs to the letter. He refused to consider the concept. Then a Admiral showed up asked some questions and listened to me about how and why and where the problem was. He called the Captain and the contractor and low and behold they found the rolled MV cables. Problem solved. Me and the crew were invited to the show the next day. A sub from sea showed up connected all 4000 amps into the stern of the boat. They had a lot of brass good food, we stayed away from the drink, at work and all. I walked over to the front gang plank and looked at the two seamen chrome helmets, shoes you could see yourself in, M-15 and side arm. Walked away and the Admiral asked me if there was anything he could do. Sure a quick visit on board. No was the answer, I thought so. He asked why Navy dock and armed seamen protecting the gang plank means nuclear tools on board.
> Admiral smiled. My security clearance from the DOE did not include ships.
> Wish I could have seen the north shore that trip.


Interesting story, I thought Marines guarded Nukes. No Marines on a Sub I have to assume.


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