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Thread: For those of you with 3 Phase wiring in your shop ...

  1. #16
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    Quote Originally Posted by Jeff Bartley View Post
    Here in VA it's ok to use tape to re-color wires.

    I just built a shop and ran a 3-phase system using romex. Just use the proper guage for your circuits and blue tape.

    And do yourself a favor and keep the black/red/blue consistent on all your breakers, outlets, and plugs!

    The nice thing about 3-phase is that amp loads are lower so you can use a lighter gauge (less expensive) wire. I think my 5hp Oliver saw only pulls 12.3 amps!

    Good luck with your shop Tom.
    Thanks Jeff. Those are good points about the lighter gauge wire and wiring consistency. For anything 5HP or less I can use 12/3 instead of 10/3, which is not only less expensive but a lot easier to pull. 10/3 Romex is pretty stiff. From my research, it sounds like folks like to put the manufactured "wild" leg on T3, so that it doesn't potentially wreak havoc with contactors, starters, etc...although there seemed to be less consensus on which color wires should be associated with T1, T2, and T3.

    My new shop is in Crozet, so not too far from you.

  2. #17
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    Crozet isn't far at all Tom, I bought a used dewalt planer years ago from a fellow in Crozet......can't remember his name though.

    It's good to know another woodworker in the area!

  3. #18
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    Quote Originally Posted by Bill Dufour View Post
    ... Heat shrink comes in many colors...
    This is my preferred method for ID'ing color code change.
    "Anything seems possible when you don't know what you're doing."

  4. #19
    Quote Originally Posted by Tom Bain View Post
    Yes, a 240 Volt system and I was planning on coloring the white ("neutral") wire to blue since I won't need a neutral for 3 phase. That's interesting about the 150V limitation ... do you not have electric ovens or dryers than run on 240V??
    Three phase systems stepped down to residential friendly voltages are usually 120/208. In every municipality I've worked you have to ask and pay extra for 240 volts.

    If your three phase panel is your only panel you need a neutral. That means 3 hots and 1 neutral are needed to feed your three phase panel.

    As for using romex, I've installed and worked on a lot of three phase systems but never have I seen romex used. You need to check your local codes to see what they allow.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

  5. #20
    Quote Originally Posted by Jeff Bartley View Post
    Here in VA it's ok to use tape to re-color wires.

    I just built a shop and ran a 3-phase system using romex. Just use the proper guage for your circuits and blue tape.

    And do yourself a favor and keep the black/red/blue consistent on all your breakers, outlets, and plugs!

    The nice thing about 3-phase is that amp loads are lower so you can use a lighter gauge (less expensive) wire. I think my 5hp Oliver saw only pulls 12.3 amps!

    Good luck with your shop Tom.
    The standard for the Chicago and suburbs (six counties) is Black/Red/Blue for A/B/C phases respectively on 120/208v systems and Brown/Orange/Yellow for A/B/C phases respectively on 277/480v systems. Larger cable is color coded with tape to identify the phases. Wire #10 and smaller was phase colored coded. Later in my career some of the larger contractors would buy the big cable color coded.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

  6. #21
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    Quote Originally Posted by Julie Moriarty View Post
    The standard for the Chicago and suburbs (six counties) is Black/Red/Blue for A/B/C phases respectively on 120/208v systems and Brown/Orange/Yellow for A/B/C phases respectively on 277/480v systems. Larger cable is color coded with tape to identify the phases. Wire #10 and smaller was phase colored coded. Later in my career some of the larger contractors would buy the big cable color coded.
    I'm not sure what line 3-phase is here, my panel is fed from a Phase Perfect so it's 240 Wye, no neutral. The line voltage is actually pretty steady at 246 volts. I wish it were less, I have a couple machines that need 200 and 246 seems a bit out of the safe range to run a 200 volt machine.

    Julie, thanks for clarifying the Black/Red/Blue. I'll have to look inside the phase perfect to see how it's labeled. When the system was first set up I had to swap two lines in the jointer; it was spinning backwards.

    And Tom, if you're considering a phase perfect you're welcome to come up and check out the one I have installed, it's the 10hp. I have it wired from the main panel to a disconnect. It then feeds a 3-phase panel.

  7. #22
    Just run it in emt. You can pull multiple circuits in a 3/4" pipe. Any more I would rather run pipe than BX. Not a fan of exposed wire even in a home shop.

    There is no 4th wire or neutral when using a RPC.

    I always brought my single phase to a disconnect, then fed to RPC control panel/idler/3phase panel.

  8. #23
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    I've always seen the same color codes as Julie referenced on 3 phase systems.

    If you're pulling wire through conduit, it's easier to pull stranded wire than solid. PVC conduit is a joy to work with, and I highly recommend a ratcheting conduit cutter.

    In my shop, I have both RPC fed 240V circuits and generator fed 240 and 480 circuits. The RPC is wired to a dedicated panel via transfer switch that allows me to use either RPC or generator power.

  9. #24
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    Quote Originally Posted by Julie Moriarty View Post
    snip...
    As for using romex, I've installed and worked on a lot of three phase systems but never have I seen romex used. You need to check your local codes to see what they allow.
    Julie:

    If not Romex, is the method to pull individual wires through conduit (e.g. 3 or 4 10 ga insulated wires)?
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

  10. #25
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    Alan, a lot of Julie's professional work was in the Chicago area where conduit is required even in residential, if I'm not mistaken. No "Romex" permitted and individual wire conductors are generally pulled through conduit. Pulling individual conductors in the conduit also allows you to put in exactly what you need including supporting multiple circuits on the same path.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  11. #26
    Quote Originally Posted by Alan Lightstone View Post
    Julie:

    If not Romex, is the method to pull individual wires through conduit (e.g. 3 or 4 10 ga insulated wires)?
    I probably first need to clarify... Jim's comment about conduit being code in the Chicago area is true but there have been instances I've worked outside the conduit mandated area, though that does not represent much of my overall experience. But since moving to Florida, romex is everywhere but I have yet to see it used in 3 phase systems. But it's important to note the vast majority of 3 phase systems are found in commercial and industrial applications where romex is rarely used.

    To your question - yes, if you're not using NM type cable (romex) or some metallic flexible cable with conductors already installed, you install the conduit and pull in the wire afterward. The conduit has to be properly sized for the conductor size and number and there shouldn't be more than 360 degrees of bend between junction boxes, panel, unilets, etc - any point where you can access the wires.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

  12. #27
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    Appreciate all the insight here, and a couple more questions for the conduit experts:

    1) I’m understand the concept of conduit fill limits and such, but my question is whether the ground wire(s) are counted as conductors or are they effectively ignored for conduit fill purposes?

    2) I’m used to Romex, so by default there is a separate ground wire for every circuit. It occurs to me that if one uses conduit that wouldn’t necessarily need to be the case, and a single ground wire from the panel could be “branched off” as needed to each machine, receptacle, etc .... Is that typical, or is a separate dedicated ground wire still pulled for each circuit?

    I’m still leaning toward Romex but want to give the conduit approach due consideration.

  13. #28
    I’m understand the concept of conduit fill limits and such, but my question is whether the ground wire(s) are counted as conductors or are they effectively ignored for conduit fill purposes?
    When discussing wire fill in conduits, the NEC only refers to "current carrying conductors". I've gotten into it with more than one inspector as to whether a neutral is a current carrying conductor. Some say "no". Others disagreed with that. One particular "discussion" involved 4-5 electricians vs. one of our own, who retired and became the electrical inspector. He knew all of us form having worked with us in the past. We all knew he was both very smart and very abrasive, when he wanted to be.

    In the end he "allowed" us not to count the neutral as a current carrying conductor. The disagreement was regarding the use of a trough that ran over a bunch of panels. We brought 3/4" EMT from points out on the floor space into the trough. From there we used the trough as a distribution point so we could get the appropriate circuits into the designated panel. Lots of wires crossing back and forth in the trough. Code says no more than 9 current carrying conductors in any cross section of the pipe, trough, etc. If neutrals were included, we would have had to tear out a lot of installed work.

    But, to answer your question, there was no debate about ground wires being current carrying conductors. I've never heard of even the worst of the inspectors try to pull that one.

    It occurs to me that if one uses conduit that wouldn’t necessarily need to be the case..
    As for metallic conduit being used as the ground - all the time. Rarely did the specs call for us to pull in a ground wire. And never did an inspector require a ground wire in conduit. One exception to the no ground "rule" was for isolated ground systems. In the early days of computers, the isolated ground system started popping up in office buildouts. That soon became a standard for any application where computers were to be used. A green wire with a yellow tracer (stripe on the wire) was pulled in from a panel that had an isolated ground bus in it. IGs were pulled in with each A/B/C network.

    But for everything else, the case ground of the conduit was the accepted standard. However, I do remember a few conversations about set screw fittings coming loose over time and maybe the use of those types of fittings should require a separate ground. When I piped my garage with EMT, using set screw fittings, I pulled in a ground. I did that not because of the set screws but because I knew the potential for rust degrading the case ground. All of the exposed metal was painted with a rust inhibitor but adding the ground was too easy a step to omit.

    ...and a single ground wire from the panel could be “branched off” as needed to each machine, receptacle, etc .... Is that typical, or is a separate dedicated ground wire still pulled for each circuit?
    If you pull a ground wire in conduit, unless the specs say different, you only need one ground conductor per pipe. That wire is a secondary means of grounding. The case of the pipe provides the primary means. Of course it is assumed the conduit, fittings and boxes are all one well-bonded case ground. Forget to tighten a set screw in a coupling or fail to tighten the locknut of a connector and you've created a weak link in the case ground.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

  14. #29
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    Thanks Julie, that is super helpful info. One last question — do you prefer solid or stranded wire? I’ve read that stranded is easier to pull, but it’s kind of a pain to terminate compared to solid.

  15. #30
    They now make a 12-2-2 NM wire for circuits requiring Arc Fault breakers. So you have an extra conductor in there.

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