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Joined: Jun 2004
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When using MC, AC -- which are bundled factory colors -- the Code permits #6 thru #14 to be re-identified. Think switch-legs.
That option does NOT exist for EMT runs where it is obvious that the correct color can be pulled in at no extra expense.
Of late, there is a trend to use fully covered feeders. Very handy.
On all commercial jobs out my way we see mixed 277 and 120 volt grounded distribution. Yes, separate colors and MC are ordered.
Because the neutral for the 120 run is 30 degrees delayed behind the 277 neutral -- they CANNOT run on the same conductor. That's why the Code has the OP's noted provision.
BTW, delta and wye diagrams come from Tensor Mathematics. When you drop the tensor diagram for a Wye transformer inside the Delta tensor you can see that the three legs split the interior vee's in half. So...
Each Vee = 60 degrees Cut in two = 30 degrees So when delta waves are transformed into wye functions they lag by 30 degrees -- because the media is an inductor.
If, for any reason, these neutrals get crossed over you get terrific harmonics on them as 'circulating current.'
Tesla
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Joined: Jul 2004
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Caution :opinion bit on: When I think "reidentifiy" I think "change type of conductor" (like like using white for an ungrounded conductor). If you are using other than green, gray or white as ungrounded conductors any additional tape is just informational, not reidentification. (like putting B O Y tape on a black 12ga wire to signify it is 480v) I agree they do make MC cable in a wide variety of configurations/colors and if I was wiring a whole building I would get some but I don't think the code requires that I buy it if I am just hooking up a troffer on a 408/277 wye. AFC doesn't seem to be bragging about having violet/gray anyway. I would put violet tape on the hot tho.
Greg Fretwell
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Joined: Aug 2006
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That option does NOT exist for EMT runs where it is obvious that the correct color can be pulled in at no extra expense. I guess this is what i am looking for. What is the code reference?
Be kind to your neighbor, he knows where you live
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Joined: Jul 2004
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If you are looking for a reference to putting purple tape on a black wire and using it for an ungrounded conductor, I don't think you can find a rule against it. All of the reidentification rules I know are in articles about grounded and grounding conductors. (green, gray and white ID going one way or the other)
Greg Fretwell
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Joined: Aug 2006
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[quote] If you are looking for a reference to putting purple tape on a black wire and using it for an ungrounded conductor, I don't think you can find a rule against it. That is what i was looking. as i mentioned before, i was under the impression that re-ID of smaller colored insulated conductor was not allowed. Thank you all. I Learn something new everyday.
Be kind to your neighbor, he knows where you live
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Joined: Jul 2004
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That is my opinion, your mileage may vary.
Greg Fretwell
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Posts: 349
Joined: April 2004
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