3 Phase rotation?

[PA BEN]

How do you check 3 phase rotation? And would you ever rotate a bank counter clockwise? The reason I ask is that at my old utility [I’ve only worked for two] I was taught to always rotate a bank clockwise. Red, white and blue. Blue being the high leg. I was taught this from day one as an apprentice. Swap red or white until I got clockwise rotation. Here I will swap the white and blue. On a Y Y bank I just rotate it clockwise, land the colors where they fall. Now I’m finding 3 phase pad mounts at my new utility rotated counter clockwise [not all but some] red being the high leg here. The lineman before me took a permanent marker and wrote counter clockwise on the inside door with the colors. Just would like hear what others are doing out there.

[Downunder]

Hi Ben,

I think I might be able to help, but just need to stitch up some of your terminology which is a bit different to some of ours here in Australia. Electricity is electricity no matter what part of the world you're in....it's just how we say it that changes.

Could be a long discussion for the boards....email me at ericsgrandpa@hotmail.com.

Cheers, DU

[Meat]

Correct me if I'm wrong but the industry standard is red for the high leg and look for a clockwise rotation and mark accordingly.On a yy I start from the left with red find clockwise and mark it.Be safe.

[PA BEN]

As a lineman before I replace a transformer or service etc, I will check rotation before I d-energize so when I finish it has the same rotation so as not to screw up the customers motors.

[scammy]

pa ben,perhaps you are seeing the inside electricins work,,,,your s should be clockwise,,,,,he must match up to you ..in the old days lineman accomodated this ,,but today we are liable ,,,scammy

[tramp67]

:confused: Things depend on which end of the wire you are on. The NEC, which governs inside wiring, the normal color code for 120/208 wye is black, red, blue. For 277/480 wye it is brown, orange, yellow. For 120/240 delta, it is black, orange, blue; with the wild leg being orange. 240/480 delta would be brown, orange, yellow again; the wild leg being orange. The NEC states that the wild leg SHALL be coded orange. Panels are always wired ABC, clockwise rotation. White SHALL only be used for grounded, current carrying conductors, ie. system neutral.
Once you hit the utility side, there's a lot of difference of opinion and color coding. Most utilities I've run across go with red, white, blue orientation left to right in a padmount or on a cluster mount transformer bank. When it gets to the customer end, whatever the rotation is at the service connection that gives the customer what they need is how it's labeled, generally either ABC or CBA. The high leg is predominantly marked white, and is labeled as B phase.
As far as primary goes, the labeling A, B, C starts from the station transformer, and is marked on system maps. Underground cabling is typically marked red, white, blue; A, B, C, respectively.
As far as rotation meters go, they don't care what color is with which phase, as long as the voltage rotation is in the proper order. This meaning that if you get a clockwise rotation with red as A, white as B, blue as C, you will still get the same rotation if you hook red up to B, white to C, and blue to A, or red to C, white to A, blue to B. Once you transpose just two leads, then you will get an opposite rotation.
On new electrical installations with three phase motor loads, an electrician can hook up all the motors to the panels before having power available, and have them all connected for a clockwise rotation because there are test instruments out there that you can hook up to motor leads, give the shaft a spin in the direction it is supposed to turn, and the instrument will give a rotation indication on the leads. Something that comes in very handy on large well pump motors to keep from spinning the shaft sections apart the first time power is applied! Also, better industrial electrical installations will have phase loss/reversal relays that will prevent equipment from starting if a phase is missing or if the rotation somehow got reversed, such as from a transformer changeout. Relays are inexpensive, some of them cost less than $50. ;)

[thrasher]

We have a few OLD services where the meter base is counterclockwise however the service inside the building is clockwise because the electrician has swapped middle and right between the CT cabinent and the panel box. This was especially common on 120/240 open delta (where they would move the high leg). If we hookup a new service we go clockwise. For the already existing we match what was there. Just one more thing to check. By the way, we don't mark any leads with white anymore we have substituted yellow.

[500 KVA]

Your probably starting to see that things are done differently everywhere you go. When in Rome!

Rotation only matters when the customer(s) are already existing on the three phase bank or line. You cannot change them at that point. You must put them back in the same rotation as they were prior to any work you have performed. That will burn up motors.

They do have new technology that will prevent the customer from being put back into service when it senses the rotation is incorrect. The customer must purchase this, and it is NOT on all customer equipment. Probably very few but it's out there.

On new customer hookups it does not matter. They must hook up to what the Utility provides to them. Although there is a unwritten policy that clockwise should be the preferred hook up, it is NOT the rule by any means.

As for how to take rotation, you should know how to use a rotation meter by now. Try to always use the same color for the high leg if there is one in your bank. I use blue or "c phase" for my 208 on a 120/240/208 Wye-Delta. Then watch the motor spin and make sure you have all three lights light up signifying that all 3 phases connected to the clips are energized. It will spin with only 2 of the 3 phases energized. Very slowly.

Remember when changing 2 secondary leads to change rotation on a Wye-Delta Bank, never swop using the high leg. Wye-Wye Banks do not have a high leg and it will not matter which 2 legs you can change.

Tape consistantly. Always mark before cutting. Always write down everything you could possibly think of on a note pad. Write it on the padmounted transformer door.


Take rotation at the customers panel, not just at the bank. Just another method of double checking everything. You write it all down on that note pad. Every apprentice MUST carry one. Every Journeyman should too.

When in doubt- ASK! Keep asking until you understand. Don't be that monkey that always shakes his head. It is important to know and understand everything about what you are doing. Ask Questions all the time. The only dumb question is the one you don't ask.

[tramp67]

Well said, 500. Although if you were to hook up a new industrial customer with a bunch of 3 phase motor loads, and they had already hooked up their end while the utility engineer was deciding which way he wanted the printing facing on the underground PVC conduit, I think they would have issues with you if you told them they will have whatever rotation you decide to give them. Once things hit the customer's main disconnect, everything is consistently color coded, and rotation and phasing orientation is maintained throughout their system. It is much easier to swap a few connections at the transformer than to rewire dozens or hundreds of motors, and the customer has the expectation that they will have clockwise rotation at their mains, along with the voltages they requested from the utility.
Thrasher, it's good to hear you are getting away from marking phases with white tape! Helps end some of the confusion when the customer has white markings on their end, and you can't put a white phase with it! Two other special color codes for the NEC are, of course, green for ground conductors, and grey is used to mark neutral conductors, generally on 277/480 systems.

[500 KVA]

The couple of Utilities I have worked for make the rules. New customers will get what we give them. It is their responsibility to make their rotation what they need it to be. Everything has already been engineered and approved before they get the okay to begin work. Our rules are very specific and have been around for a long time. Contracors know the drill here.

Yes it could be easier for us to change the connections in some instances, but If you have staggered buswork in a pad mounted transformer it isn't so easy. You then get into changing primary phases. Then you have a cable with c imprinted into the jacket on a B Module.

the company will not spend the time and money to fix something when our rule is spelled out loud and clear to the contractor wiring a building.

We sometimes can have 10 runs of 500 Copper on each phase. We aren't going to sleeve out all that and move it. I think changing primary phases around for that to be foolish too.

Our rule is that they need to change their equipment if the rotation is wrong. We will not do it. We are just too busy and have problems keeping up with our normal scheduled work. We aren't going to worry about a contractor who did not follow our rule.

[Stick-it]

New construction = whatever we give them. The customer has to match us.

Existing = we check before we denergize and reconnect the same way.

And yes, red white blue - brown orange yellow, etc...

[BigClive]

Here in the UK the rotation is supposed to be red-yellow-blue or brown-black-grey with the new euro phase colours. That said, if I was changing distribution gear I would put the phases to an existing installation back exactly the same way they had been rotating before to avoid any liability for damaged gear.

Many large machines tend to have a phase relay that not only checks rotation, but also failure of single phases, and shuts off the control circuit. With very new equipment using variable frequency drives it doesn't matter since the AC is converted to DC as soon as it enters the motor controller and then converted back to any frequency of AC required.

When I worked with Hussmann refrigeration doing heavy refrigeration plant the Copeland compressors could run wither way, but if they had been running most of their life in one direction they would often fail quite quickly if they were reversed. The bearings just seemed to bed in for a particular direction after a while.

[adamr_41]

Can you get rotation if only 2 x-fmrs are enengized on a 3 ph. bank?

If not , How can you determine correct rotation if 1 or 2 transformers burn up.
I have never ran into this situation before. And was curious to know.

[tramp67]

Can you get rotation if only 2 x-fmrs are enengized on a 3 ph. bank?

If not , How can you determine correct rotation if 1 or 2 transformers burn up.
I have never ran into this situation before. And was curious to know.

If you burn up an xformer on a delta connected secondary, you can still utilize it as an open delta, and you will still have your three phase rotation. If it's a wye connection, you lose your three phase. But once you replace the bad pot, your rotation will still be the same, since you are only changing one out and the connections will be going back the way they were. If you were to pull the secondaries out of all the pots to change out one, then you better keep track of where they came from.
If all else fails, and you forgot to check, or lost your notes, or whatever, you can always hook things back up and have the customer "bump" a three phase motor and see if it's going the correct direction. If you are working in an area that has decent electrical inspectors, you can just about bet your paycheck on the customer's mains needing clockwise rotation. You can check there after you re-energize your bank.

[tramp67]

When I worked with Hussmann refrigeration doing heavy refrigeration plant the Copeland compressors could run wither way, but if they had been running most of their life in one direction they would often fail quite quickly if they were reversed. The bearings just seemed to bed in for a particular direction after a while.

Kinda like a wire brush wheel on a microscopic level. When it's new, all the peaks are uniform, after a run-in, the peaks all tend to bend over and lose most of their bite. Spin it the other way, and it bites in, just like the bristles on the wire brush.
Sounds like you've worked both sides of the meter, too!;)

[PA BEN]

500 KVA
This is the thing!
Your probably starting to see that things are done differently everywhere you go. When in Rome!


I'm too old and close to retirement to get to upset about rotation. I'm on the lineman side of the meter. Before I open a bank, add a transformer, change the service, parallel a bank I will mark rotation and find the high leg on Y deltas. Always clockwise, but here It could be clockwise or counterclockwise. Just wondering what other utilitys are doing.:D [When in Rome]

[Orgnizdlbr]

If you burn up an xformer on a delta connected secondary, you can still utilize it as an open delta, and you will still have your three phase rotation. If it's a wye connection, you lose your three phase. But once you replace the bad pot, your rotation will still be the same, since you are only changing one out and the connections will be going back the way they were. If you were to pull the secondaries out of all the pots to change out one, then you better keep track of where they came from.
If all else fails, and you forgot to check, or lost your notes, or whatever, you can always hook things back up and have the customer "bump" a three phase motor and see if it's going the correct direction. If you are working in an area that has decent electrical inspectors, you can just about bet your paycheck on the customer's mains needing clockwise rotation. You can check there after you re-energize your bank.

I worked a trouble call on a 03:00am callout. It was after a voltage conversion from 4160 to 12470, a contract crew replace the straight 4160 pots with the new pots, 240 closed delta bank, well when they built it they swaped the high side taps on the lighting pot and had the h2 bushing as the primary and the wing pots the opposite with the h1 being the primary. talk about a head scratcher at 3:00 am the bank fed a bakery, when the baker showed up to start his day his equipment was all effed up. He called an electrician who found screwy voltage in the main panel, then they called us....equipment burned up....took us a while to realise what the problem was in the dark. i wont ever forget that call....

[BigClive]

Had a call to a theatre job where the phases had been swapped for some reason. I think it was internal to the building, perhaps a new distribution board or something. The only direction critical load was the stage curtain system which promptly shot past it's limits because it was going in the wrong direction and stalled. I really don't know if they tried to fix it themselves or it was just an average non technical electrician who did it, but they decided that they could perhaps fix it by reversing the open/close buttons on just one of two control points but still didn't allow for the limits so they ended up trying to swap them about but then a wire popped out and there was no drawing so they tucked the wire up out of sight (!) and called ME!

What a job that was! No drawing so I had to reverse engineer the control system, work out where the rogue wire was supposed to go (it shared a terminal with other wires) and then swap everything back to where it had been and swap two phases. All done in half an hour, but with quiet cursing as I discovered each bodge.

[500 KVA]

You are getting too old? For what? Wanting to learn something?

From the sound of your question it is apparent to me that you have never worked anywhere but the place you are at. You only know that one way that has been passed on there for decades.

I hate this saying. "That's the way we've always done it!"

I originally thought you were a newbie, but now you say you are old and close to retiring.

So why did you even bother asking if you really didn't care? Just wanting to feel like you're a part of things?

I hate when things are unclear. What the hell are you? You claim to be something one time, then another thing another time.

Hell with it! You're just a dumb ****ing grunt to me!

[500 KVA]

If your wye point is floated on that three phase Wye-Delta it will not work if one transformer is taken out.

An Open-Wye Open- Delta requires the wye point to be tied down.

You would have two single phase transformers in series.

Inspectors in rural areas don't necessarily care if the Utility is clockwise or counter clockwise. Why should they anyway?

It will work for the customer either way. It is the customer who needs to have his electrician wire up his panels for the motors correct operation.

The only time it matters is when you are dealing with the service or bank of an existing customer!!!!

What the hell is so hard to understand?

[shaun]

New construction = whatever we give them. The customer has to match us.

Existing = we check before we denergize and reconnect the same way.

And yes, red white blue - brown orange yellow, etc...

Us too. Existing construction, phases/rotation are kept the way they were. New stuff, they get what we give 'em.

[NU Limey]

I agree with Stick It and others. Every ute is a little different. New construction is customer responsibility. Existing is ours. If you cannot determine because of damage have a rep. of the customer on site to make sure his rotation is correct when its reenergized. hopefully in most cases you can swap two hot legs to correct the problem. With so many systems out there everyone needs to make sure they know what their dealing with. If you don`t know ask someone locally that does.

[PA BEN]

You are getting too old? For what? Wanting to learn something?

From the sound of your question it is apparent to me that you have never worked anywhere but the place you are at. You only know that one way that has been passed on there for decades.

I hate this saying. "That's the way we've always done it!"

I originally thought you were a newbie, but now you say you are old and close to retiring.

So why did you even bother asking if you really didn't care? Just wanting to feel like you're a part of things?

I hate when things are unclear. What the hell are you? You claim to be something one time, then another thing another time.

Hell with it! You're just a dumb ****ing grunt to me!

Beings you asked why. I'll tell you. I'm not new to the trade 23years, I've never burned up a bank, I know how to check rotation. I can learn NEW ways of doing this line of work. {I'M too old to lose sleep over how my new co-workers check rotation} REMEMBER WHEN IN ROME! This is the only utility they have worked at, I just wanted to know how other lineman did it at their utilitys or I wouldn't have asked. Before you run me off of YOUR venue here mybe you should not be a hot head and ask a question. I bet even you could teach me something. I sure wouldn't want to be an apprentice with you as my Journeyman:mad: If you hate when things are unclear ask a question.

[500 KVA]

How many ways are there to check rotation if you've been in the trade 23 years? I learned by my 18th month in my apprenticeship.

I called it. You haven't been anywhere but a po-dunk co-op. A single county Boomer!

You cannot judge me on my training ability with apprentices from my impatience from dealing with dinga-lings such as a 23 year Lineman asking how to check rotation.

I'm all for learning new ways. I learn new stuff every day. I'm not afraid to say I don't know something. I don't lie about things though. Read your initial post. "How do you check 3 phase rotation?" " Would you ever rotate a bank counter clockwise?"

BINGO! All your words pal! Sounds to me like maybe I may have done you some good in your apprenticeship. Maybe you needed someone to put a boot up your ass!

I don't hate. I call Bullshit when I see it. My Rome would have probably run you off before you got acclimated! As for the boards, have at it. Keep on running your mouth as much as you want to. I know I will!

I again will ask you a question. Are you a Journeyman? Grunts can be in the trade 23 years too. You probably watched someone for 23 years and figured out you can talk the talk for a little bit.

[PA BEN]

You have the power. Yes I'm a journeyman and yes I've never worked in the real 500 KVA world. 21 years at one and two at my new utility. And the power of my pen might not be as clear as yours. But when I ask "HOW DO YOU CHECK ROTATION" I MENT "YOU" NOT TO LEARN HOW. Sorry I'm not clear enouth for you. Is this how you pay back someone who gave you a compliment on you giving good advice? :eek: Boom down it will be OK. Lifes to short to get so upset.

[tramp67]

Well, PaBen, looks like 1/2MVA left his feelings on his sleeve again. Put 10 linemen on a job, and everyone knows there will be 19 different ways to tackle the work. 1 lineman will drag, 2 will get in a fight:mad: , 5 will do the work, 1 will decide he won't work with the other 9 idiots, and the last one will storm off complaining about how @%&*%ed up the whole job is!!!:eek:

[dbrown20]

PA BEN is at least a 2 county boomer. dbrown20

[loadbreak55]

We go RED WHITE BLUE left to right and could give a rats butt if it's ccw or cw on new construction.Then we write it on the inside for that middle of the night replacement call.;)

[dbrown20]

We go RED WHITE BLUE left to right and could give a rats butt if it's ccw or cw on new construction.Then we write it on the inside for that middle of the night replacement call.;)

What he said. dbrown20

[dwalla-walla]

If it is a new installation the customer must match us. It is up to him to get what he wants. If it is something we are doing or a case of trouble then we have to go back with the same rotation as before. We hook up the rotation meter R,W,B. Just be sure you hook it the same both times. On open delta we put Red to the open end, White to the tie bar, and blue to the high leg.

[Brooks]

I've seen red white blue, red green blue, red yellow blue, black red blue, brown orange yellow, yellow brown orange, no tape one band tape two bands tape, one two and three bands, one clean conductor one knife knick two knife knick, no bolts one bolt bottom of lug one bolt top of lug, no bolt one bolt two bolts...

They only mistakes I have had to troubleshoot involved someone that either didn't check at all, ASSumed based on prior workers tape or marks on equipment or just flat out didn't have clue what they were doing.

Worked on one system that required workers tape to be removed at the end of the job. Ensures the next guy goes through the proper steps. ASSume nothing.

Tape is for continuity only????????????

Open Wye Delta, the lighting pot goes on the leading phase. Verified by attaching c phase lead of rotation meter to the high leg, b phase lead to the x1-x3 tie and a phase lead to the single lead. Should rotate clockwise. If it doesn't reconfigure the bank.


Each place that I have worked, new service- we do not guarantee rotation but as always try to work with the customer. Existing installations we put it back the way it was found. In the case where I can't determine the original configuration, such as a dig in or storm, I notify customer that an electrician should be contacted to verify a match with inside wiring prior to operating equipment.

OK, head hurts now.

[Circuit Rider]

Good point tramp67!! But don’t forget about that one Lineman building the job in a way it screws the next guy that works on the pole.
We were instructed a while back that because there was an arrow on our rotation meters pointing in a clockwise rotation we were to hook up the Red White and Blue leads in a way that produced a clockwise rotation. I just laughed and told the guys on my crew that I was taught to hook up the leads Red, White and Blue left to right. Write down on the meter panel CW or CCW along with your initials and the date. The way I figure if you always hook up your leads the same way RWB you only have one thing to remember CW or CCW. Plus writing the rotation on the panel in indelible ink, gives the next crew that comes along changing out bad transformers a 99.999% chance of getting the rotation right. I say 99.999% because all of the rotation meters in our company are the same brand and rotate the same direction if hooked up Red White and Blue left to right.

[A Laska Lineman]

Do not rely on rotation meters all being wired the same way. I have seen two rotation meters, same brand, side by side, both hooked red/white/blue rotating oppisite directions. For this reason we use the same rotation meter on disconnects/reconnects to insure proper rotation. If not, we are extra carefull when coming back hot. Someone might write clockwise inside the can but if your meter is wired different it means nothing.

[reppy007]

Im not going to say that Im right...........but this is how I was taught........we have always rotated left to right at the meter base.......red,white,and blue..........this is done at the line side meter jaws........beyond that isnt any concern of mine..............now if we are lucky enough and the situation happens to be where we find an existing service that is counter-clock wise........then we can go back counter clock-wise.........but most times I have found poles and transformers on the ground..........so then we will re-build the bank............leaving the rotation clock-wise at the line side wires at the meter base.............

[Pootnaigle]

Ummmmmm On the line side of any 3 phase mtr base there should always be colored tape corresponding with the rotation meter......... red , white,n blue. I know white is also used to mark neutrals but it shud be obvious what it designates if its at the meter socket and not off to one side. Truth is we never rotated a new service that was the lectricians job. WE did however allways check rotation before and after disconnecting a 3 phase service.We also used Red for the high leg if there was one. By the way I have an old Knopp rotation meter that I bought on ebay if anybody wants to buy a cheap one.Purdy sure it wuz boosted frum sum utility but it werks

[ratbastard101]

We check rotation in meter can Red white blue left to right and mark whatever we get as far as clockwise or counter-clockwise. Our 3 phase pad mounts if hooked up correctly are clockwise red white blue left to right.

Obviously we match whatever the existing service is on old services. On new services the electrician is supposed to match whatever we give them, however we try to build new stuff clockwise.

We used to mark OH services red, white, blue (ABC)corresponding with the leads on the rotation meter. We would mark UG services black, red, blue (ABC). With some people unable to get it we changed to marking everything except 480 black, red, blue (ABC).

I am a firm believer that there should be a standard for whatever company you work for. There are times when someone is there to do a hook up that is not the same person who disconnected a service. If there is no standard then there is no way of knowing what markings mean what.

Many people get caught up on using or not using certain colors, I don't care what color you mark what with as long as I know what the colors represent as far as phase marking.

Just my 2 cents.

[Pootnaigle]

Umm Yeah I remember once a crew from another locality came to assisst us on a conversion and they rotated all the 3 phase stuff they came across and we rotated what we came across. Turned out they used white for a hi leg and we used red. Later when we put that stuff in service most all of it was wrong. So there definately needs to be a universal standard.

[rob8210]

Anything I have worked on we marked 1(a) - red , 2(b) white, 3(c) blue and rotation was always clockwise. Now I have used just about every trick possible to identify phasing for continuity purposes based on what was available on the truck.

[lewy]

The electrician is responsible for all secondary connections on an U.G. 3 phase pad so rotation is his problem, but we always hook up the primary RWB top to bottom. On O.H. we would again mark the wires at the stack & check rotation, but rotation is up to them on initial hook up.

[Lineman North Florida]

Similar to what RB101 said, their does need to be a standard, I started a thread several years ago about rotation and color coding, I stated up front that I didn't want a class on how to use a rotation meter as I knew how to do that I just wanted to know how other places marked. What I learned is that it is mosly geographical, around hear it has always been the policy of power company's to mark a high leg or kitty leg BLUE, you go to a different region of the country and it might be RED, it really doesn't matter what color you mark it so long as it's a standard wherever you are at, so if one man cuts it loose another can hook it back up with confidence. As far as different meters giving different rotation on the same service (ie 1 says CW and the other says CCW when hooked up exactly the same way), I've never heard of that, and would think if it did happen that it was an isolated incident. Has anyone else ever heard of this? I saw a rotation meter once on a truck that the WHITE lead or B lead had been taped BLACK, when I asked about it I was told that he marked all services BLACK,RED,BLUE, and since the meter already had a RED and a BLUE lead all he needed to do was tape up the B phase lead BLACK, I tried to explain to him that no lineman coming behind him would know what he had done and he still didn't get it.:D

[reppy007]

Similar to what RB101 said, their does need to be a standard, I started a thread several years ago about rotation and color coding, I stated up front that I didn't want a class on how to use a rotation meter as I knew how to do that I just wanted to know how other places marked. What I learned is that it is mosly geographical, around hear it has always been the policy of power company's to mark a high leg or kitty leg BLUE, you go to a different region of the country and it might be RED, it really doesn't matter what color you mark it so long as it's a standard wherever you are at, so if one man cuts it loose another can hook it back up with confidence. As far as different meters giving different rotation on the same service (ie 1 says CW and the other says CCW when hooked up exactly the same way), I've never heard of that, and would think if it did happen that it was an isolated incident. Has anyone else ever heard of this? I saw a rotation meter once on a truck that the WHITE lead or B lead had been taped BLACK, when I asked about it I was told that he marked all services BLACK,RED,BLUE, and since the meter already had a RED and a BLUE lead all he needed to do was tape up the B phase lead BLACK, I tried to explain to him that no lineman coming behind him would know what he had done and he still didn't get it.:D

I can see that happening.........same lineman goes behind another.........time after time.......he gets close to narrowing that first lineman down...............finally he knows who doing it that way............lots of yelling.

[Pootnaigle]

Ummmmmmm ever seen sumbody use colored tape to mark phasing and someone come along behind em thinkin it was rotation? I have .unless sumbody is incredibly lucky it dont werk so good either