Raintight EMT fittings

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c_picard

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USA
When installing in a conduit body, should the gasket be removed to ensure the fault current path is adequate?

Are these fittings listed for grounding in a way that allows the EMT to be used as an EGC?

I have heard that the gaskets do not last, so in a few years they are not raintight, and they will not provide a path for fault current. Thoughts?
 
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Gregg Harris

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c_picard said:
When installing in a conduit body, should the gasket be removed to ensure the fault current path is adequate?
No
Are these fittings listed for grounding in a way that allows the EMT to be used as an EGC?
Yes
I have heard that the gaskets do not last, so in a few years they are not raintight, and they will not provide a path for fault current. Thoughts?
Click to expand...

Made of EPDM and has a long life span provide it is not exsposed to oils, same material that is used in roofing,flashing etc.
 
Dennis Alwon

Dennis Alwon

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These are listed fittings and should be used as such. I have never seen any info that supports that the gasket causes a bad connection. I don't think it would be listed if it did what you say.
 
ActionDave

ActionDave

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Different brands of fittings have gaskets that work better or not so good when threaded into conduit bodies.

My experience with Arlington RT fittings is that the rubber gasket squeezes out and over the fitting when you tighten it into a threaded hub. Bridgeport fittings have metal sandwiched between two pieces of rubber that works better. But on the other hand the Bridgeport fittings have that annoying internal piece of plastic that make it hard to insert the conduit.

Throw away the gasket or throw away the internal plastic. It's a wash. The whole thing with the new style RT fittings is a solution in search of a problem anyway.
 
LEO2854

LEO2854

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Ma
Dennis Alwon said:
These are listed fittings and should be used as such. I have never seen any info that supports that the gasket causes a bad connection. I don't think it would be listed if it did what you say.
Click to expand...


I agree as long as they are made up wrench tight they should have no problem.
 
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NetNathan

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As far as grounding goes...
I never use EMT as ground path, too many connection issues, I run a ground wire.
 
Ponchik

Ponchik

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Grounding aside, I don't think the conduit bodies are listed to be used with EMT fittings. They are listed for RMC or IMC conduit.
 
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GoldDigger

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edward said:
Grounding aside, I don't think the conduit bodies are listed to be used with EMT fittings. They are listed for RMC or IMC conduit.
Click to expand...
:thumbsup:
The difference between running threads and tapered pipe threads rears its ugly head again. :angel:
The EMT RT fittings are intended for use with a nut on the other side of a knockout or drilled hole in an enclosure.
A conduit body expects any necessary seal to be made by the tapered threads.
If you try to mix them, the threads will not provide any seal while the taper may prevent the gasket of the RT fitting from seating properly.
 
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GoldDigger

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macmikeman said:
You guys are picking on me, I'm gonna report you to the moderators. I always behave at Mike Holt.com. Always.
Click to expand...
Reminds me of the recent story about a Texas high school football coach who is under formal investigation because of bullying charges brought by the parents of student at the opposing school that his team beat 90+ to zero.
The really interesting thing is that the kids on both teams enjoyed the game and the coach was doing his best not to run up the score.
 
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macmikeman

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Planet macmikeman
I just searched in vain for an hour and a half for some pictures of an exterior emt 2" service run I did 5 or 6 years ago. Disk crashes and all... I couldn't get any 2" raintight emt compression fittings anywhere on the island then and didn't have the time to do a ship from the mainland gig. I went into a local good hardware store, found where they keep o-rings, got some that fit 2" emt really well. I put them on before putting the conduit into standard compression fittings , rolled em up tight to the fitting and then sealed all with silicon dap. I have been back there a couple of times for various add ons , and they are still holding up fine and dandy. No way any rain water got inside that run of conduit.
 
LEO2854

LEO2854

Esteemed Member
Location
Ma
macmikeman said:
I just searched in vain for an hour and a half for some pictures of an exterior emt 2" service run I did 5 or 6 years ago. Disk crashes and all... I couldn't get any 2" raintight emt compression fittings anywhere on the island then and didn't have the time to do a ship from the mainland gig. I went into a local good hardware store, found where they keep o-rings, got some that fit 2" emt really well. I put them on before putting the conduit into standard compression fittings , rolled em up tight to the fitting and then sealed all with silicon dap. I have been back there a couple of times for various add ons , and they are still holding up fine and dandy. No way any rain water got inside that run of conduit.
Click to expand...

Many guys do not know that there are two types of compression fittings and think all of them are rain tight..
 
Ponchik

Ponchik

Senior Member
Location
CA
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Electronologist
What is the purpose of rain tight fitting anyway when the old one worked fine and the conductors in the conduit are THWN anyway?
 
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