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

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Wyo721 said:
Where is this in the code article?
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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.
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Chris
 
OK Where is an approved compound?

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.
 
Wyo721 said:
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.
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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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Wyo721 said:
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.
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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, .....
 
Wyo721 said:
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.
Click to expand...

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
 
I was going on the premise that Approved meant listed

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?
 
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.
 
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)
 
Mustwin351 said:
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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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?
 
Mustwin351 said:
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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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.
 
is it for ease of install, or to seal out water??

the graphite sprays are conductive
see https://www.sprayon.com/product-cat...nts/dry-film-graphite-lubricant-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.

kwired said:
It generally seals well enough that you will get more water inside as a result of condensation then that joint will ever leak.
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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.
 
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.:thumbsup: 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.:)
 
Frank DuVal said:
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.:thumbsup: 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.:)
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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/tn...MI_v6m177p1gIVQ2B-Ch3c-gQaEAQYASABEgJylvD_BwE
 
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kwired said:
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.
Click to expand...



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.
 
AKElectrician said:
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.
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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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