NM conduit that can handle higher temperatures of an attic

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Eric E

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Is there a suggestion for what type of NM conduit to run in higher temperature environments like an attic, or do I need to stick with metallic conduit?

I’ve searched around, but can’t find a good solution for this. For background, I’m running CAT6 in a residential attic (2 story, single-family home). There’s a section of the attic that is a real pain to access, and additional LV cables will be pulled through there over time. So, the client wants a conduit to span the approximately 15’ leading from the 2nd story, into the attic, and to the more accessible area.

I’d like to stick with flexible NM conduit, but ENT and similar products can only be used up to ambient temperatures of 122F, and the attic might exceed that. LFNC is rated for higher temps, but it’s an odd use of it. I’d like to avoid FMC since it would require running a ground. The conduit can be properly secured along its length.
 
So these raceway is only for Cat6 cable? I would run FMC if you're concerned about the ambient temp of the attic. Metal sleeves do not require bonding.
 
I think you are overthinking this, it's only 15 feet and who cares what it looks like. I think you will be OK with PVC. Are you just pushing it through laying on the joists or will there be bends?

-Hal
 
Thanks for the quick feedback and ideas. There's a bunch of bends (not exceeding 360, but enough that flexible conduit is needed). And yet, it's only for CAT6.
 
Eric E said:
Thanks for the quick feedback and ideas. There's a bunch of bends (not exceeding 360, but enough that flexible conduit is needed). And yet, it's only for CAT6.
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Then go with FMC. I've run many basement to attic runs of FMC over the years. Even have a few in my own home for future cables.
 
infinity said:
Then go with FMC. I've run many basement to attic runs of FMC over the years. Even have a few in my own home for future cables.
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Awesome. Thank you so much for the recommendation. It was the bonding of the FMC that was holding me back from it, since I usually work with NM. I didn't realize that this would be considered as a sleeve and be exempt.
 
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I would definitely use ENT or Resi-Gard. Most ENT states it can be used in residential attics up to 3 feet above bottom of the ceiling joists.

Since this is just being used as a chase for LV cables the listing doesn't matter anyway.

LFNC is the worst raceway to pull through followed by metal flex. ENT is easy to pull through unless its a very long run and it gets installed like a roller coaster. I have pushed 100 amp feeders through relatively long runs of ENT with close to 360 degrees of bends.
 
Don't forget the Yellow 77 fella's . Best lube out there , but I admit it is the messy one , me , I don't care, I just use it constantly.

I use it for pulling NM cables thru a series of holes in wood framing as well. No shame.
 
curt swartz said:
I would definitely use ENT or Resi-Gard. Most ENT states it can be used in residential attics up to 3 feet above bottom of the ceiling joists.

Since this is just being used as a chase for LV cables the listing doesn't matter anyway.

LFNC is the worst raceway to pull through followed by metal flex. ENT is easy to pull through unless its a very long run and it gets installed like a roller coaster. I have pushed 100 amp feeders through relatively long runs of ENT with close to 360 degrees of bends.
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Thanks so much. You're very correct -- UL 1653 (the ENT spec) says that it covers products intended for use:
  1. a) at a maximum continuous operating temperature of 75°C (167°F);
  2. b) at a maximum ambient temperature of 50°C (122°F);
  3. c) in attics provided that the ENT is installed no higher than 900 mm (3 ft) above the bottom of the ceiling joist, and the ENT material is rated minimum 60°C (140°F)
It was the "maximum ambient temperature of 122°F" that was throwing me off, which I figured an attic would exceed.
 
SceneryDriver said:
Or use PVC the whole way. ENT is miserable to pull through, especially to get a fish tape through when there are bends.


SceneryDriver
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What? ENT is extremely easy to get a fix tape through and to pull through. The gaps on the inside are small enough that a properly made up fish tape head glides around them, and the ribs reduce the pulling tension. That is my experience anyway.
 
Strathead said:
What? ENT is extremely easy to get a fix tape through and to pull through. The gaps on the inside are small enough that a properly made up fish tape head glides around them, and the ribs reduce the pulling tension. That is my experience anyway.
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It must have been the particular stuff I was using, but I clearly remember it was absolutely terrible to get the fish tape through, and then to pull the conductors back through. And they were relatively straight runs. I've sworn the stuff off since then.


SceneryDriver
 
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