conductive thread paste?

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c_picard

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Is anyone familiar with a conductive thread paste used on threaded
RMC conduit? I've used it in the past, just can't seem to remember a
brand name, and fella at the supply house thought I was nuts.
I seem to recall it being a code requirement for field threaded rigid in wet
locations?

Anyhow, the folks I'm working for now are using teflon paste...they must think they're
plumbers!! How abouththat ground fault path?

thanks
 
c_picard said:
Is anyone familiar with a conductive thread paste used on threaded
RMC conduit? I've used it in the past, just can't seem to remember a
brand name, and fella at the supply house thought I was nuts.
I seem to recall it being a code requirement for field threaded rigid in wet
locations?
Anyhow, the folks I'm working for now are using teflon paste...they must think they're
plumbers!! How abouththat ground fault path?

thanks
Click to expand...
Only required where [additional] corrosion protection is required: 300.6(A)

For conditions where corrosion protection is required, see 344.10(B).
 
T&B brand is called Kopr-Shield.

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Kopr-shield, Noalox, and the other such compounds are generally listed for use on your mechanical connections as well. While UL does not have a formal 'standard,' they most certainly do have an evaluation procedure.

What about ordinary anti-seize? Well, the 'listing' issue is about to become moot. While I don't want to name names at this point, I am personally involved in getting the '500-lb gorilla' of commercial anti-seize compounds UL listed.
 
We specify on all our RMC installs. Cr-H STL-8 is the one that I've used in the past. But I will admit it has confused a few people in the past. Have had some of the wannabe plumbers, too.
 
Kopr-shield, Noalox, and the other such compounds are generally intended for corrosion resistance and may not necessarily be intended to use as thread sealers although they are likely effective sealers for non pressurized piping like electrical raceways.

Teflon pastes do not impede electrical contact between parts in a threaded joint they simply fill voids that allow the contained meduim to leak out of the joint. The threads still mash together and if properly tightened will have just as much contact between each other as if no paste were used at all. Water pipes used as a grounding electrode are likely to have a tefoln based sealer in any fittings and they are still an effective electrode. Same is true for other piping systems that are required to be bonded - if teflon based sealers actually insulated the fittings from the piping we would have to bond around every fitting.
 
renosteinke said:
Kopr-shield, Noalox, and the other such compounds are generally listed for use on your mechanical connections as well. While UL does not have a formal 'standard,' they most certainly do have an evaluation procedure.

What about ordinary anti-seize? Well, the 'listing' issue is about to become moot. While I don't want to name names at this point, I am personally involved in getting the '500-lb gorilla' of commercial anti-seize compounds UL listed.
Click to expand...

If it's the brand I think, cool! I use it extensively and have a couple big jars of it.
 
kwired said:
Kopr-shield, Noalox, and the other such compounds are generally intended for corrosion resistance and may not necessarily be intended to use as thread sealers although they are likely effective sealers for non pressurized piping like electrical raceways.

Teflon pastes do not impede electrical contact between parts in a threaded joint they simply fill voids that allow the contained meduim to leak out of the joint. The threads still mash together and if properly tightened will have just as much contact between each other as if no paste were used at all. Water pipes used as a grounding electrode are likely to have a tefoln based sealer in any fittings and they are still an effective electrode. Same is true for other piping systems that are required to be bonded - if teflon based sealers actually insulated the fittings from the piping we would have to bond around every fitting.
Click to expand...

But Teflon tape DOES insulate. I saw the gas company running pipe and they used three wraps of tape along with paste. I have often wondered how this affects the fault path.
 
K8MHZ said:
But Teflon tape DOES insulate. I saw the gas company running pipe and they used three wraps of tape along with paste. I have often wondered how this affects the fault path.
Click to expand...

Have you ever tried to put a pipe together this way and then attempt to pass a current through it? I'm willing to bet the threads will cut through the tape and you will still have good conductivity. Gas companies usually use dielectric fittings at the meter so that their underground piping does not become a grounding elecrode, many of their installers may not realize it but that is why.
 
kwired said:
Have you ever tried to put a pipe together this way and then attempt to pass a current through it? I'm willing to bet the threads will cut through the tape and you will still have good conductivity. Gas companies usually use dielectric fittings at the meter so that their underground piping does not become a grounding elecrode, many of their installers may not realize it but that is why.
Click to expand...

I have seen devices (sensors and switches) that used threaded connections for electrical contact not work because of it. If the tape is put on correctly, the two metal pieces to not touch each other.

For example, it's common to see switches for radiator fans in automobiles with just one wire. The other connection is threaded into the engine block. If you put Teflon tape on the threads of the switch there is a very good likelihood that the switch won't work (well, the switch works, it's just that there is nothing to switch to). I have seen this with my own eyes. If you wrench down enough to split three wraps of tape all the way through, you are overtightening.
 
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