NEC Code-Conduit size

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william peot said:
Is there a NEC code that state 3/4" conduit is the min size allowed?
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There is not. See, for example, the Annex C tables. They include 1/2 inch conduits. But is there a particular application that relates to your question? Are you asking if a particular situation requires a minimum size conduit?

william peot said:
Witch Article?
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Interesting choice of words to use on Halloween! :grin:
 
I agree with Ken and Roger,

This sounds like an engineers specification. I have worked on a lot of jobs with specs that mandate a minimum of 3/4" conduit.

Chris
 
Sounds like a job spec to me also.....it might not be "code", but it pays to follow specs :D
 
Does anyone know why people spec. a minimum of 3/4"? Seems like a big waste of someones money to have a raceway with 2 or 3 #12 wires in it.
 
infinity said:
Does anyone know why people spec. a minimum of 3/4"?
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I have no idea,

infinity said:
Seems like a big waste of someones money to have a raceway with 2 or 3 #12 wires in it.
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And I agree.

Roger
 
infinity said:
Does anyone know why people spec. a minimum of 3/4"? Seems like a big waste of someones money to have a raceway with 2 or 3 #12 wires in it.
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Probably because it's a CYA issue for the EE. As long as the specs exceed the NEC, he's covered. And the specs for one job are routinely copied (electronically) to the next, and some don't get changed.

Another reason may be for future expansion/loads.

But it's not a waste of MY money, just the customers. If it's spec'ed that way, I charge accordingly.
 
3/4" is a TIA spec, is it not??

edit -- wanted to add that the smallest KO in a low-voltage nail-up box is 3/4 for ENT terminators.
 
LarryFine said:
To fit 25- or 50-pr phone wire?
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I remember when all telephone drops were 1" so you could fit a 25 pair amphenol jack through the conduit. But the 3/4" minimum spec for say a switch stub up which will have only 2 conductors in it seems rather over kill.
 
And before long we will only need a 3/8 (or smaller) for the one fiber.

Roger
 
Does anyone want to know what is totally absurd? That the phone company specs a 4" conduit for their lines. And then what do they do once said conduit is installed? Install a single 25 or 50 pair cable in it. :rolleyes:
 
peter d said:
Does anyone want to know what is totally absurd? That the phone company specs a 4" conduit for their lines. And then what do they do once said conduit is installed? Install a single 25 or 50 pair cable in it. :rolleyes:
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I think alot of that has to do with future expansion and the ability to pull multiple tubes of interduct in the conduit. That and maybe the fact that their "fish tape" is big enought that is takes a dedicated truck. What I found crazy was that on a new construction job, part of the under street duct bank they used for a new fiber run was installed in the 1920's.
 
Astek said:
I think alot of that has to do with future expansion and the ability to pull multiple tubes of interduct in the conduit. That and maybe the fact that their "fish tape" is big enought that is takes a dedicated truck. What I found crazy was that on a new construction job, part of the under street duct bank they used for a new fiber run was installed in the 1920's.
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Perhaps, but as Roger pointed out, with the advent of fiber optics, such a spec still seem absurd. I've never seen them install an innerduct into any of their conduits around here, at least the ones that go from their outside network to the customer's building. Maybe they do that in their U/G installations, but it doesn't seem like the norm around here.
 
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