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#210260 06/06/13 08:39 PM
Joined: Jun 2012
Posts: 75
Member
Hi,
Is there a NEC requirement or other code that requires schedule 80 PVC if ran under a roadway?

Please quote article if you don't mind.

I have a duct bank with schedule 40 and 3" of concrete..seems to me it should be schedule 80.

thanks

GW


Don't drive and TEXT! Drive now TALK LATER!
2017 / 2014 NEC & Related Books and Study Guides
Joined: Jul 2004
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G
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Not that I could cite.
When I was working on the MM99 toll booth on I-75 I did spend some time with the engineers and they say the spec's the duct banks should be 5-6 feet below the sub bed of the road. Florida DOT says there is quite a pounding going on under a road when you have big trucks and lots of traffic.

Most of the actual protection is the concrete itself and the pipe is just a place holder until the concrete cures.


Greg Fretwell
Joined: Apr 2002
Posts: 7,279
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A real, real stretch would be 'subject to physical damage'.

I would say that the PE that did the design has the option of spec'ing Sch 80, but I could not cite Sch 40 for a duct bank with any NEC Article.


John
Joined: Jun 2012
Posts: 75
Member
Hi,
Thanks Greg and Hotline...our specs call for "schedule 40 HEAVY WALL" there is a diff between reg sch 40 and sch 40 heavy wall am I correct? I contacted cantex and they said they would send me the specs and that the wall thickness is different.

Thanks

again for your excellent knowledge.

Greg

Last edited by akmaster; 06/07/13 11:38 AM.

Don't drive and TEXT! Drive now TALK LATER!
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G
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There is sch 40 and sch 80. I am not sure what "heavy wall" means.
It sounds like the guy doing the spec is clueless.


Greg Fretwell
Joined: Jun 2012
Posts: 75
Member
Greg,
Yes he is clueless and has me running around like a blind dog in a meat house looking this crap up!

Sch 40 and Sch 80 is all there is besides UTILITY grade PVC that is THINNER than sch 40 and 80!!

I told them install it and have 3" coverage of concrete all around and dye the concrete red and use metal warning tape within 12" of finished grade...

thanks Greg

regards

Greg


Don't drive and TEXT! Drive now TALK LATER!
Joined: Jul 2004
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Over on the plumbing side there is sch200 (thinwall PVC), typically used for DWV or sometimes irrigation but I do not know of any equivalent in electric world.


Greg Fretwell
Joined: Feb 2002
Posts: 2,233
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Greg,

AT a large senior citizens complex around here, the EE stated that all underground MV wiring had to be in sch 20. Then it had red concrete poured all around it. I can't remember the thickness, I think it was 1' of concrete. I had a second EE sign off on the MV wiring.

Joined: Jul 2004
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G
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Sch 20?


Greg Fretwell
Joined: Feb 2002
Posts: 2,233
H
Member
Yeah, it was real thin stuff, but it was encased a lot of concrete so the EE didn't care. I questioned the EE but it was his design. This goes back almost 15 years ago, but I am pretty sure it was sch 20.

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