Sealing conduit from temperature difference

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brother

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I notice in my area it appears that the 'sealant' that is to be installed inside conduit to help prevent water and condensation when entering buildings from outside because of temperatures is not enforced or forgotten. NEC 2020 300.7

Recently had a complaint about a water leaking from conduit in a tele data room. Conduit comes though building from outside (LB on other side of wall) and was full of water. No sealant. other conduit run just ran straight through, no c, lb etc.. close to the entry point to put a sealant.

Do inspectors in anyone elses area look for a 'c , LB , box, etc.. on the other side of the wall when conduit is coming from inside to outside that would show proof there is sealant in pipe? Suprisingly, it appears that some electricians forget about it alot.
 
In the damp Seattle area, I always seal conduits. Conduit is supposed to be arranged to drain.
Polywater makes a really good conduit seal I have used on fiber optic, and its approved for the use, per the NEC.
Plus it can be removed, and its much better than duct seal.
 
I always use duct seal. The object is to keep different temperature air from coming in contact with each other. A waterproof seal is not required just something to stop the air movement.
 
Tom - which polywater sealant do you like? They seem to have a few to choose from. There is a foam type, and one you squirt into some open cell foam.
 
Polywater FST, easy to use, works great, and can be removed. There is a new version Polywater FST Mini for smaller conduits. Duct seal is good for air sealing (and condensation) but not water.
 
brother said:
I notice in my area it appears that the 'sealant' that is to be installed inside conduit to help prevent water and condensation when entering buildings from outside because of temperatures is not enforced or forgotten. NEC 2020 300.7

Recently had a complaint about a water leaking from conduit in a tele data room. Conduit comes though building from outside (LB on other side of wall) and was full of water. No sealant. other conduit run just ran straight through, no c, lb etc.. close to the entry point to put a sealant.

Do inspectors in anyone elses area look for a 'c , LB , box, etc.. on the other side of the wall when conduit is coming from inside to outside that would show proof there is sealant in pipe? Suprisingly, it appears that some electricians forget about it alot.
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As a rule, what should not always be done. It seems they are checking. But in practice, some forget about it.
 
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