Phased Rotation

[trobarch]

As an owner/architect for a department of correction and as an owner/architect for over 35 years, I have never been asked about "phased rotation (PR)" or our requirement/standards during new construction for 'phased rotation'. I have overseen construction of entire new campuses and/or added multi-building additions to existing campuses and never stated a desired standard for PR. Is there a standard of care, as an owner, that all buildings within a new campuses have the same 'PR' or that a new building added to an existing site match the existing buildings? Is there a maintenance standard I need to set-up or address for PR?

Just wondering and need your advice.

Tom

 

[brian john]

The Spec is in most jobs we bid on, how long it has been there I can't say. We generally don't perform this test as part of our testing, though we do include a line item in the quotation to the EC, generally the customer does not want to pay for a return trip after the site is energized and they say they will check rotation. 99.9% Of the jobs we see are ABC, Clockwise.

 

[kwired]

This is not an NEC requirement, but could be a designer/user specification.

 

[brad9m]

We have a mix

We have a mix

Most of what you see will be ABC, but I've seen ACB in several installations.

 

[hillbilly1]

Never have seen such a specification, must be a regional thing. Most
POCO's in the southeast US deliver CCW at the service, don't know what it actually is at their transformer lugs, but they always connect our end CBA. Generators on the other hand are always set ABC.

 

[hillbilly1]

As an owner/architect for a department of correction and as an owner/architect for over 35 years, I have never been asked about "phased rotation (PR)" or our requirement/standards during new construction for 'phased rotation'. I have overseen construction of entire new campuses and/or added multi-building additions to existing campuses and never stated a desired standard for PR. Is there a standard of care, as an owner, that all buildings within a new campuses have the same 'PR' or that a new building added to an existing site match the existing buildings? Is there a maintenance standard I need to set-up or address for PR?

Just wondering and need your advice.

Tom

Oh, wait a minute, your talking about the government, I wouldn't doubt it then.:roll:

 

[kwired]

Never have seen such a specification, must be a regional thing. Most
POCO's in the southeast US deliver CCW at the service, don't know what it actually is at their transformer lugs, but they always connect our end CBA. Generators on the other hand are always set ABC.

But isn't "A" "B" and "C" which ever terminal someone decides to label them, or at least which coil lead they decide to bring to the terminal? I can rearrange the leads internally in the transformer and still have the same rotation at the terminals, and no one would know any different.

 

[hillbilly1]

But isn't "A" "B" and "C" which ever terminal someone decides to label them, or at least which coil lead they decide to bring to the terminal? I can rearrange the leads internally in the transformer and still have the same rotation at the terminals, and no one would know any different.

Exactly, the transformer may be ABC, but the POCO color code may be different from ours, such as most installations would be BOY, and the POCO is terminating it YOB or a another combination. I have seen them re-mark our end to a color that suited them, not necessarily even the same colors we had.

 

[kwired]

Exactly, the transformer may be ABC, but the POCO color code may be different from ours, such as most installations would be BOY, and the POCO is terminating it YOB or a another combination. I have seen them re-mark our end to a color that suited them, not necessarily even the same colors we had.

Yes they do remark our end, usually to match the leads on their rotation tester. I have asked before and nobody has a good answer - why do rotation meters have a "white" lead? POCO puts a white mark on a phase conductor for potential future use in testing rotation, and then electrical inspector asks why there is a white mark on an ungrounded conductor:roll:

 

[Jraef]

The issue as I have always understood it is, when you have a "campus" of several buildings, you want to specify that all buildings have the same phased rotation as each other. That way if your Maintenance Dept. moves a piece of equipment from one building to another and fails to recheck rotation, it is less likely to be damaged.

 

[brian john]

My belief is I could care less about the color scheme, BYO, OYB, BOY whatever, We match what is in the building and match rotation as well. Do do otherwise only causes problems at some point in the future.

 

[Hv&Lv]

Yes they do remark our end, usually to match the leads on their rotation tester. I have asked before and nobody has a good answer - why do rotation meters have a "white" lead? POCO puts a white mark on a phase conductor for potential future use in testing rotation, and then electrical inspector asks why there is a white mark on an ungrounded conductor:roll:

That is exactly the reason I have my rotation meter taped yellow on the white lead. I have no idea why someone would remark your end. Are they removing the tape or just adding their own? I have added my own tape to correspond with the rotation meter if the electrician has used something other than red and blue. Around here, red black blue is popular. I have some electricians that are under a rotation clause, I assumed it was to match the existing building or a generator.

I can connect it abc at the pot, and it could be anything at the service. same goes for the motor. We are not responsible for rotation unless we change a service wire or a bank. Of course, at that time, it is either all wrong or all right.

 

[Hv&Lv]

Never have seen such a specification, must be a regional thing. Most
POCO's in the southeast US deliver CCW at the service, don't know what it actually is at their transformer lugs, but they always connect our end CBA. Generators on the other hand are always set ABC.

It has to be a luck thing, and not on purpose. I know we have some stations that have CCW and some that are CW. The service wires for three phase are usually factory marked phase A, phase B, etc. when we tape them, we try to tape them red to A, and blue to C, but we don't check rotation to see that it is any certain way. That is up to the EC. If they are all CCW, that is probably luck, not purpose.

 

[mivey]

It has to be a luck thing, and not on purpose. I know we have some stations that have CCW and some that are CW. The service wires for three phase are usually factory marked phase A, phase B, etc. when we tape them, we try to tape them red to A, and blue to C, but we don't check rotation to see that it is any certain way. That is up to the EC. If they are all CCW, that is probably luck, not purpose.

I will agree and that is true with many utilities.

 

[jumper]

Yes they do remark our end, usually to match the leads on their rotation tester. I have asked before and nobody has a good answer - why do rotation meters have a "white" lead? POCO puts a white mark on a phase conductor for potential future use in testing rotation, and then electrical inspector asks why there is a white mark on an ungrounded conductor:roll:

The Navy also uses white for an ungrounded conductor identification. White is B phase in three phase ship wiring.

 

[hillbilly1]

It has to be a luck thing, and not on purpose. I know we have some stations that have CCW and some that are CW. The service wires for three phase are usually factory marked phase A, phase B, etc. when we tape them, we try to tape them red to A, and blue to C, but we don't check rotation to see that it is any certain way. That is up to the EC. If they are all CCW, that is probably luck, not purpose.

I don't believe it's so much a luck thing, because they have a set way of doing things like us. They mark their phases on the primary side too so that when they disconnect or remove a transformer, it will be phased back just the same. If a storm comes through and tears down all of the lines, once they rebuild them, they don't go through checking rotation of every transformer on the line. If they happen to get one backwards from what it was, it is usually due to a lineman mistake or markings gone if a lateral.

 

[hillbilly1]

The Navy also uses white for an ungrounded conductor identification. White is B phase in three phase ship wiring.

Yeah, there's the right way, the wrong way, and the Army way !(in this case, the Navy):lol::lol:

 

[kwired]

That is exactly the reason I have my rotation meter taped yellow on the white lead. I have no idea why someone would remark your end. Are they removing the tape or just adding their own? I have added my own tape to correspond with the rotation meter if the electrician has used something other than red and blue. Around here, red black blue is popular. I have some electricians that are under a rotation clause, I assumed it was to match the existing building or a generator.

I can connect it abc at the pot, and it could be anything at the service. same goes for the motor. We are not responsible for rotation unless we change a service wire or a bank. Of course, at that time, it is either all wrong or all right.

Reason you mention is exactly why POCO marks equipment, in the event they change a service wire, bank, ice builds up and tears down the entire pole, etc. Then they have reference to what rotation was and don't have to run user equipment to verify correct rotation.

One time had a situation where they had to rebuild bank, they checked rotation and it was correct, but no one bothered to make sure wild leg was still in same position as original. OOPS.

 

[Hv&Lv]

I don't believe it's so much a luck thing, because they have a set way of doing things like us. They mark their phases on the primary side too so that when they disconnect or remove a transformer, it will be phased back just the same. If a storm comes through and tears down all of the lines, once they rebuild them, they don't go through checking rotation of every transformer on the line. If they happen to get one backwards from what it was, it is usually due to a lineman mistake or markings gone if a lateral.

A good lineman can have multiple spans of primary torn down and never reverse rotation on banks without checking with a meter. The lines go back a certain way all over the country.( Or at least on the east side of the Misssissippi where I have worked on storm trouble.)

 

[hillbilly1]

A good lineman can have multiple spans of primary torn down and never reverse rotation on banks without checking with a meter. The lines go back a certain way all over the country.( Or at least on the east side of the Misssissippi where I have worked on storm trouble.)

Yeah, poles are easy, it's the direct burial stuff that's a little harder if not marked.