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

  1. #1
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    RMC treads where does the code dis-allow use of thread compounds?

    Where is this in the code article?

  2. #2
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    Quote Originally Posted by Wyo721 View Post
    Where is this in the code article?
    The code does not "dis-allow" the use of thread compounds on RMC Threads.

    In fact if the threads are subject to corrosion then approved thread compound is required.

    See 300.6

    300.6 Protection Against Corrosion and Deterioration.
    (A) Ferrous Metal Equipment. Ferrous metal raceways, cable
    trays, cablebus, auxiliary gutters, cable armor, boxes, cable
    sheathing, cabinets, metal elbows, couplings, nipples, fittings,
    supports, and support hardware shall be suitably protected
    against corrosion inside and outside (except threads at joints)
    by a coating of approved corrosion-resistant material. Where
    corrosion protection is necessary and the conduit is threaded
    in the field, the threads shall be coated with an approved electrically
    conductive, corrosion-resistant compound.
    Chris

  3. #3
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    OK Where is an approved compound?

    I have read that but is there was someplace that said you could not use thread sealant and Teflon tape type compound to seal joints, guess that is the question I am looking for the answer to.

  4. #4
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    Quote Originally Posted by Wyo721 View Post
    I have read that but is there was someplace that said you could not use thread sealant and Teflon tape type compound to seal joints, guess that is the question I am looking for the answer to.
    It is not particularly likely, but there is a risk with Teflon tape that you do not get reliable electrical connections across the joints.

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  5. #5
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    Quote Originally Posted by Wyo721 View Post
    I have read that but is there was someplace that said you could not use thread sealant and Teflon tape type compound to seal joints, guess that is the question I am looking for the answer to.
    What ever compound you use must provide conductivity. So Teflon tape is a no as well as Silicone.
    Lead plate ( if you still have some) , Galvanize spray, .....

  6. #6
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    Quote Originally Posted by Wyo721 View Post
    I have read that but is there was someplace that said you could not use thread sealant and Teflon tape type compound to seal joints, guess that is the question I am looking for the answer to.
    The NEC does not specifically say that thread sealant and Teflon tape is not permitted.

    The key to that section is "Electrically Conductive". I would not approve Teflon tape as an electrically conductive corrosion protection.

    The term "Approved" is defined as acceptable to the authority having jurisdiction.

    Chris

  7. #7
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    I was going on the premise that Approved meant listed

    Do any of the sprays or lubes talked about having a listing for use in electrical connection or systems?

    I was sure at some point in the past, there was a restriction on the treaded joints have any kind of lubricant?

    They say your memory is the second thing to go, cannot remember what was first?

  8. #8
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    molykote 111 is very unlikely to have any impact what-so-ever on wires or anything.
    one may argue that you may be adding ohms at the junction when a lubricant is use, so if say you use the metal conduit as egc there is an argument there, but i have not seen evidence that the ohms change.

    they do make conductive greases, but there is test data out there that shows these do not help much, if any help at all, in lowering ohms of say a lug bolted to a rail with some "conductive" grease in between.

    so, from what i can see, 111 silicone grease has no impact, and using "conductive" grease is no help, so i am not sure what argument there is to be had.

  9. #9
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    Copper sheild

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  10. #10
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    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)

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