Phase order necessary on breaker?

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ruxton.stanislaw said:
You are right that it makes no difference whatsoever to the electrons; only to electricians and maintenance etc. A lot of the concept I posted involves information getting lost in translation. Look at the bigger picture and say you are balancing overall the L-L single phase loads across multiple sub-panels, but the panels are connected sporadically/in random order without specific phase identification. That makes it a lot more difficult to keep track of, especially during maintenance where it could be reconnected in a different order. It is like drawing straws; the system could be started after re-torquing/cleaning and by chance find that a significant chunk of the major L-L loads are on the same two phases.

Safety, is ensuring the correct leg of a circuit is turned off (that could be the fault of an electrician poorly depending too much on the colour of a wire or its identification). For proper equipment function, that would be phase rotation of simple motors primarily. Some VFDs will also complain about it with an error code.

Installations where a certain colour of wire or indication tape is consistently matching the respective phase make these issues a lot easier. Having three black wires for example, leaves a lot of room for error or guessing.
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Yes if you need to balance a service by going to various subs, then definitely uniform color coding is helpful .

Safety - I am not seeing that one at all

Function - phase rotation is a crapshoot anyway so I don't see uniform color coding making a bit of difference.

I do in fact generally maintain color coding/phasing, just I guess out of professionalism, but it serves little purpose in practice, for most installations.
 
ptonsparky said:
Phase rotation works well if you keep track. Same connection throughout should give you the same rotation.
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Had an asphalt plant that was built from new.
When it was time to turn the power on, the GC asked me if we could swap the primary leads in the transformer if the rotation is backwards. They said they wired everything up the same way so all the rotation would be the same.
We do not like to do that for uniformity across the system, but to be nice I said sure. But only If we could try three or four motors first before we swapped anything.
First and second motor were backwards, he was proud until he got to the third motor..😅

Thought about sticking around to see just how many went opposite directions, but figured it wasn’t my business, so I left them to figure it out.
 
There are a multitude of issues with proper color phase/identification. For instance. Just finished a large 2 year project, miles of conductors installed, too many circuits to count. The issue stems from the number of individuals working the job and lack of knowledge between them. We had mostly 480/277v, but plenty of 208/120v. For the most part, proper phase coloring was not too difficult. But the change of men on each task, the time factor of the job, the speed we were trying to keep up with, and sometimes the lack of the proper conductor colors/tape became difficult. Especially when the men did what that wanted to, just to complete the task. I walked a lot of the job, had changes made, but not completely through the job. Larger feeders were much easier to comply with, until phase rotation was determined.
The 480/208 general colors were adhered to, just not necessarily A, B, C being the same all the time color wise.
 
Hv&Lv said:
Had an asphalt plant that was built from new.
When it was time to turn the power on, the GC asked me if we could swap the primary leads in the transformer if the rotation is backwards. They said they wired everything up the same way so all the rotation would be the same.
We do not like to do that for uniformity across the system, but to be nice I said sure. But only If we could try three or four motors first before we swapped anything.
First and second motor were backwards, he was proud until he got to the third motor..😅

Thought about sticking around to see just how many went opposite directions, but figured it wasn’t my business, so I left them to figure it out.
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Somebody didn't do their homework first.

I wouldn't have even thought it was something to ask of a utility.
 
From my experience, I try to maintain clock-wise A-B-C rotation throughout a facility's power distribution system. There is uniform continuity for future expansions. If there is a rotation issue on new piece of equipment's initial power up bump testing, we correct it at that items first connection to the distribution system, be it a disconnect, circuit breaker or unit's power connection provision. Altering rotation to the incoming service to benefit a single item will then effect correctly rotating A-B-C connected equipment that now has to be changed. If a piece of equipment has a number of rotation sensitive items and some are out of sync with each other, indicating the entire item was not tested prior to delivery, I would suggest the manufacturer be contacted to correct that issue, not the electricians connecting the equipment who will be charging for their time.
 
electrofelon said:
Ok fair enough if you have multiple of the same product. I wonder how often products are consistent though. We had multiple identical RTU's on a project and they were all random.
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The only time I worked with RTUs, they both had 3 different colors of wire: blue, pink, and yellow. I connected both with the wrong rotation; afterwards I learned that red/yellow/blue is the designation for A/B/C phase in India and SE Asia. It comes from an old UK color code that's not used anymore, but I guess it's still used where those RTUs were manufactured.
 
ruxton.stanislaw said:
You are right that it makes no difference whatsoever to the electrons; only to electricians and maintenance etc. A lot of the concept I posted involves information getting lost in translation. Look at the bigger picture and say you are balancing overall the L-L single phase loads across multiple sub-panels, but the panels are connected sporadically/in random order without specific phase identification. That makes it a lot more difficult to keep track of, especially during maintenance where it could be reconnected in a different order. It is like drawing straws; the system could be started after re-torquing/cleaning and by chance find that a significant chunk of the major L-L loads are on the same two phases.

Safety, is ensuring the correct leg of a circuit is turned off (that could be the fault of an electrician poorly depending too much on the colour of a wire or its identification). For proper equipment function, that would be phase rotation of simple motors primarily. Some VFDs will also complain about it with an error code.

Installations where a certain colour of wire or indication tape is consistently matching the respective phase make these issues a lot easier. Having three black wires for example, leaves a lot of room for error or guessing.
Click to expand...
I never seen a VFD that input phasing matters. The front end of the drive is a rectifier and you get DC output from it regardless what the input rotation is. Can even have a lost input phase with many of them and they continue to run as long as motor being driven isn't too heavily loaded.
 
Mr. Serious said:
The only time I worked with RTUs, they both had 3 different colors of wire: blue, pink, and yellow. I connected both with the wrong rotation; afterwards I learned that red/yellow/blue is the designation for A/B/C phase in India and SE Asia. It comes from an old UK color code that's not used anymore, but I guess it's still used where those RTUs were manufactured.
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Motors don't care about conductor color, they care about the rotation.

With any given wye system there is no such thing as A phase until you designate one conductor as that phase. Delta systems you most often must designate high leg or grounded phase as the B phase, but code says nothing about it's rotational relationship to the other conductors either so you can designate either of the others as A phase or C phase.
electrofelon said:
Ok fair enough if you have multiple of the same product. I wonder how often products are consistent though. We had multiple identical RTU's on a project and they were all random.
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I believe motors designed per NEMA typically will all run the same direction if you connected same input sequence to them. So if you are keeping track of what phase is which with your circuit conductors you should reliably be able to predict motor rotation. Needs of the machine can vary though.

If you ever been in the habit of pulling three blacks for one motor, three reds for another motor and three blues to a third motor all in same conduit, you know which conductors go to which motor by color but have 50-50 chance of getting the correct rotation for each one of them. A lot of the stuff I have connected is easy to bump motor and check rotation, which should be done even if you are pretty certain what rotation will be anyway. Occasionally there is machine that can't, won't or shouldn't be powered in the wrong direction.
 
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