Phase Rotation Colors ?

[jim dungar]

What difference would it make? Only the rotation is important.

It is important for paralleled power sources like with closed transition transfer switches.

 

[kwired]

It is important for paralleled power sources like with closed transition transfer switches.

Well those situations are kind of important to actually be "in phase" with one another, even if only dealing with single phase supply.

 

[tom baker]

Where I worked we always had clockwise rotation. Rolled the motor leads if rotation was wrong
For a new service, we worked with POCO to get CW rotation, and it was in our specs.
And one rainy night we lost the transformer for a submersible well, the normal supply from a dam was off due to high turbidity. This transformer never had oil put in it it. and was a 480 3 phase, it burned up in the middle of the night. I got a call and had the poco roll, they got a transformer, installed it and they needed to know the rotation on the service. With a multi stage turbine pump it will pump some water in reverse and the correct amount forward and it can be difficult to tell which is the correct rotation. Keep in mind this was all at 2 AM in the morning. This particular well produced a lot of sand and had to be flushed once started it needed to be run for a long time so stopping and starting to check rotation was not advisable.

I had the rotation records back in the office, I had to go to the office get the rotation records and then check for phase rotation. So in the future everything was to be clockwise rotation, and I had small labels I put on the service stating clockwise rotation.
I worked for a medium size water utility and reliability was critical, most locations we had multiple sources of supply and gravity fed systems but this particular well was way out in the far end. We needed it it to maintain flow and pressure.

 

[Hv&Lv]

Where I worked we always had clockwise rotation. Rolled the motor leads if rotation was wrong
For a new service, we worked with POCO to get CW

?

For a new service you get what we deliver. Up to you to roll motor leads to make them turn like you want.
Why would it matter CW or CCW at the service point?

 

[tom baker]

Phase monitors want CW. So it works nicely to have CW at service. All the three phase sites have motors and phase monitors

 

[TwoBlocked]

Hey folks, really appreciate all the thoughtful posts. It encouraged me to take another look at the NEC and try to reconcile that with what I see in the real world (a never-ending process...) Here is what I came up with:

200.7(C)(2) allows flexible cords to utilize a white, ungrounded conductor. No requirement for further phase coloring in 3-phase circuits using SO type cord with the typical Bk, Wt, Rd, Gn conductors.

Since these cords are laid up with the Wt opposite the Gn, the normal landing pattern would either be Bk, Wt, Rd or Rd, Wt, Bk depending on which end of the cord you are dealing with. In cases where a plug is installed it can be difficult (and with larger gauges impossible) to cross any two conductors. If one sequence is preferred, you would choose which end of the cord to install the plug.

In a perfect installation, I would expect to see Bk, Wt, Rd as both the landing pattern and the rotation as this would be the normal landing pattern for 240/120 split phase also. If further marking is desired, I think I would choose "L1, L2, L3" for 3 phase and "L1, N, L2" for split phase.

All right folks, let's tear apart what I've posted.

 

[TwoBlocked]

Well those situations are kind of important to actually be "in phase" with one another, even if only dealing with single phase supply.

Yep, saw a plant lose utility power when a transfer switch on the utility side stuck and the phases didn't match, although rotation was the same.

 

[ggunn]

It is important for paralleled power sources like with closed transition transfer switches.

It is only important that they agree on which is the A phase and the direction of rotation, not that any phase is absolutely the A phase.

 

[kwired]

It is only important that they agree on which is the A phase and the direction of rotation, not that any phase is absolutely the A phase.

until you run into high leg or corner grounded delta systems.

 

[jim dungar]

It is only important that they agree on which is the A phase and the direction of rotation, not that any phase is absolutely the A phase.

You are correct that there is no absolute 'A phase'. Paralleled sources, including utility grids, need to have a common reference phase and rotation.

 

[busman]

There is no code on which colors to use however the standard for 3 phase 120/208 is black, red, blue. In your case you would have to mark the white conductor with any color other than white or green.

Whatever the color scheme in the building is then you should follow it when there are other voltages like 277/480

Or Natural Grey (whatever that is)?

 

[kwired]

Or Natural Grey (whatever that is)?

pretty certain more recent code editions have eliminated "natural grey" wording and just go with white or gray for the required grounded conductor color requirements now.

I think the natural grey was the color that came out when not adding any specific coloring pigments when making the insulation?

 

[busman]

pretty certain more recent code editions have eliminated "natural grey" wording and just go with white or gray for the required grounded conductor color requirements now.

I think the natural grey was the color that came out when not adding any specific coloring pigments when making the insulation?

I was just saying that White, Grey, Green and Orange are the special colors.

 

[Frank DuVal]

I was just saying that White, Grey, Green and Orange are the special colors.

Now it is, but 20* or so years ago it wasn't. Instead of gray, it (NEC) mentioned natural.

Back then I used gray as a hot color.

*OK, maybe 30+ years ago, I've been at this a long time.

 

[don_resqcapt19]

?

For a new service you get what we deliver. Up to you to roll motor leads to make them turn like you want.
Why would it matter CW or CCW at the service point?a

While not a new service, it can be a huge issue on an existing service where the utility flops the rotation.

A number of years ago, a contractor working for the local utility replacing some medium voltage lines and transformers, reversed the rotation on the supply to one of the city's deep wells. It was a shaft driven submerged deep well pump. The backwards rotation spun the shaft apart requiring a costly fishing project to recover the pump and restore it to service.

 

[Hv&Lv]

While not a new service, it can be a huge issue on an existing service where the utility flops the rotation.

A number of years ago, a contractor working for the local utility replacing some medium voltage lines and transformers, reversed the rotation on the supply to one of the city's deep wells. It was a shaft driven submerged deep well pump. The backwards rotation spun the shaft apart requiring a costly fishing project to recover the pump and restore it to service.

Agreed. We are meticulous when it comes to existing services and rotation when we do any work

 

[texie]

I've worked with POCOs that will not reenergize a 3 phase service after doing, say, an emergency xformer changeout or such unless the owner's electrician is present and confirms rotation. Even in the rare case where rotation is marked on the service disco most won't even trust that. I wouldn't either.
As we know, some 3 phase loads accidentally run backwards is not too big a deal while others it can be catastrophic.

 

[ggunn]

until you run into high leg or corner grounded delta systems.

Of course, but in those cases it's easy to tell what's what with a voltmeter.

 

[Dzboyce]

While not a new service, it can be a huge issue on an existing service where the utility flops the rotation.

A number of years ago, a contractor working for the local utility replacing some medium voltage lines and transformers, reversed the rotation on the supply to one of the city's deep wells. It was a shaft driven submerged deep well pump. The backwards rotation spun the shaft apart requiring a costly fishing project to recover the pump and restore it to service.

I've seen a few line shaft turbines pumps with the headshaft sticking up up thru the roof after accidently being run in the wrong direction. We usually install a non-reverse rachet on the motor, or a backspin timer. The backspin timer allows the pump to stop backspinning caused by the column pipe draining.

 

[DooWop]

For many years UK 3-phase colours were red, yellow, and blue. Primary colours. Now we have this nonsense:

For three-phase cables the phase colours are brown, black and grey, instead of red, yellow and blue, respectively, and the neutral colour is now blue instead of black. Again the protective conductor is identified by the colour combination green-and-yellow.

Ya but you guys have the hot water on the right, cold on the left, and light switches are down for on.
I get very confused when in the Isles. Except at the pub.