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Thread: RMC treads where does the code dis-allow use of thread compounds?

  1. #11
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    Quote Originally Posted by Mustwin351 View Post
    Is joining together a vertical section of RMC with a coupling wrench tight enough to keep water out? (Especially if it's coming out the top of a panel)
    you can make uber tight, the small space between threads can still allow water in, a little amount.
    a little molykote 111 on M and F threads helps keep that water out.
    the Blaster graphite dry spray should be conductive, might make it easier to thread, just not sure it would seal out water.

    was this Q answered, is the thread compound for ease of threading, or to seal out water?

  2. #12
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    I have been using something like this
    https://www.permatex.com/products/lu...ize-lubricant/

    I asked a inspector about it and likes that it states "Provides good electrical conductivity."

    I find it at some autoparts stores or Amazon

  3. #13
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    Crouse Hinds makes some goo that we use.
    If Billy Idol or John Denver is on your play list go and reevaluate your life.

  4. #14
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    Quote Originally Posted by Mustwin351 View Post
    Is joining together a vertical section of RMC with a coupling wrench tight enough to keep water out? (Especially if it's coming out the top of a panel)
    It generally seals well enough that you will get more water inside as a result of condensation then that joint will ever leak.

    Interesting thought - Galvanized rigid water pipe is suitable for grounding electrode/portion of grounding electrode conductor and they are likely to use sealant of some sort on the threads....

    IMO, making the connection wrench tight mashes threads together enough there is good electrical conductivity between male/female parts of the joint, the sealant just fills in any remaining gaps.

  5. #15
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    is it for ease of install, or to seal out water??

    the graphite sprays are conductive
    see https://www.sprayon.com/product-cate...-aerosol-lu204

    probably would also allow moisture to move through since the dry film is not thick enough to completely fill the gaps in threads.

    if for sealing (and for ease of install), the Permatex® Copper Anti-Seize Lubricant seems ok, comes in jug with brush, i just not sure how it reacts with zinc on pipes.

    Permatex also has Nickel and the Aluminum versions when all copper may not be wanted (copper will oxidize, etc). the Aluminum version is a blend of aluminum, copper and graphite lubricants. the Nickel version is nickel powder in their goop, etc.

    none if it is UL listed for the RMC use, so, i might actually go a different route, take a std teflon paste used for plumbing and mix in graphite powder. inspector asks what you are using and you show them the Permatex bottle that you have your mix in
    you can even have a show-&-tell session by dumping your fluke probes in on ohms setting to show the conductivity of the paste.

    Quote Originally Posted by kwired View Post
    It generally seals well enough that you will get more water inside as a result of condensation then that joint will ever leak.

    if condensation is the process that allows water to pool inside, then i dont think it matters if the threads are sealed or not, a tight dry fitting will not be enough to counter the condensation process, etc.

  6. #16
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    I have never in 35+ years ever seen Teflon Tape insulate a connection of threaded pipe.

    There may be other issues of Teflon Tape useage, but insulating joints is a non-issue. Go ahead, try it. Hand tightening does not count!

    The Teflon Tape is actually Anti-Seize tape, allows taper pipe threads to rotate (therefore get closer) than with the same pipe wrench force on dry threads.

    I propose if Teflon Tape and other pipe dopes are actually insulating sections of pipe, the NEC would have made us bond every section of pipe to ensure a grounded piping system of water, air, gas, etc.

  7. #17
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    Quote Originally Posted by Frank DuVal View Post
    I have never in 35+ years ever seen Teflon Tape insulate a connection of threaded pipe.

    There may be other issues of Teflon Tape useage, but insulating joints is a non-issue. Go ahead, try it. Hand tightening does not count!

    The Teflon Tape is actually Anti-Seize tape, allows taper pipe threads to rotate (therefore get closer) than with the same pipe wrench force on dry threads.

    I propose if Teflon Tape and other pipe dopes are actually insulating sections of pipe, the NEC would have made us bond every section of pipe to ensure a grounded piping system of water, air, gas, etc.
    not tape, way too slow anyways.

    let me ask this Q, when it come to power/fittings/amps does 2Ω = 2Ω ?? the answer is NOT REALLY. i'll let you dig on why that is even though my Fluke meter (very very accurate) says the joint w/ or w/o goop is 2Ω.

    this goop (or the like), and mix in graphite powder. however, still seems too slow using a dip brush unless its used seldom. maybe the best is dry graphite spray?
    https://www.mscdirect.com/browse/tnp...SABEgJylvD_BwE
    Last edited by FionaZuppa; 10-11-17 at 06:24 PM.

  8. #18
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    Quote Originally Posted by kwired View Post
    It generally seals well enough that you will get more water inside as a result of condensation then that joint will ever leak.

    Interesting thought - Galvanized rigid water pipe is suitable for grounding electrode/portion of grounding electrode conductor and they are likely to use sealant of some sort on the threads....

    IMO, making the connection wrench tight mashes threads together enough there is good electrical conductivity between male/female parts of the joint, the sealant just fills in any remaining gaps.


    I think that the tapered water coupling makes a better metal to metal connection to the pipe eating a lot more teflon than a straight electrical coupling.

  9. #19
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    http://www.cooperindustries.com/cont...fications.html

    Only stuff I have ever put on Steel RMC, IMC. Electrical couplings are straight and do not make up tight like water pipe couplings that are tapered.

  10. #20
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    Quote Originally Posted by AKElectrician View Post
    I think that the tapered water coupling makes a better metal to metal connection to the pipe eating a lot more teflon than a straight electrical coupling.
    I won't disagree. How much difference between the amount of contact when comparing straight thread coupling with and without a sealant occurs IDK. The small end of the tapered pipe thread likely isn't making that great of contact either way. I still think there is good enough contact that the pipe is going to carry any fault current imposed on it by any contained conductors, not like you are ordinarily going to solely depend on a 1/2 RMC to carry enough fault current to trip a 600 amp breaker

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