PVC Ques

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vramp7

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Im putting in a underground wire for a house service. The wire is in pvc conduit. Some of the pvc conduit goes under a driveway, the trench is 24".
Does the pvc conduit have to be sch 80 under the drive, or is sch 40 ok? Ive heard rumors of this in another city I was working in. I cant find this in the code book...
 
The NEC sez that Sch. 80 is to be used where subject to physical damage. 300.5(D)(4). And according to Table 300.5 Column 3, 24 " is the min. depth for nonmetallic raceways listed for direct burial without concrete encasement... under streets,......driveways,....... So you're fine according to my code interpretation.
 
Schedule 40 is fine for your installation.

Roger
 
On this subject I have a question. Around here some jurisdictions require schedule 80 whenever the PVC conduit extends above grade. Art. 300.5(D)(4). Is this really a legitimate calling on this article or is there another article that would require this.
 
Dennis Alwon said:
On this subject I have a question. Around here some jurisdictions require schedule 80 whenever the PVC conduit extends above grade. Art. 300.5(D)(4). Is this really a legitimate calling on this article or is there another article that would require this.
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This is our requirement here in south Florida...apparently the local AHJs feel that such installations are subject to "severe physical damage."
I'm not so sure about this myself, I suppose it would depend on the location but we always comply with this requirement.
 
Pvc

Pvc

The "key", I believe, is the UL White Book. The UL listing for NMRC )DZYR) states Sch 40 is for indoor use or underground. or where not exposed to physical damage, or concrete encasemed. Sch 80 is suitable where 40 can't be used
 
So would you considered the conduit coming out of the ground subject to physical damage. I guess my question is what is subject to physical damage mean.
 
I find it somewhat ironic that sched 40 would not be allowed above grade but I could use Liquidtight NonMetalic flex with no objection from the AHJ...I would think sched 40 is more durable than the flex.:-?
 
Dennis Alwon said:
So would you considered the conduit coming out of the ground subject to physical damage. I guess my question is what is subject to physical damage mean.
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I've always wondered the same thing...weed-eaters, junk piled against, etc. is the only answer I have ever been given by inspectors.
 
Dennis Alwon said:
I guess my question is what is subject to physical damage mean.
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There is no formal definition, kind of like "nearest the point of entrance "

Roger
 
Table 300.5 has 2 areas for driveways. One says 24" driveways, streets, parking, ect.. and one says 1 or 2 family dwellings driveways is 18" for direct burial cable. I picked 18".
 
vramp7 said:
Table 300.5 has 2 areas for driveways. One says 24" driveways, streets, parking, ect.. and one says 1 or 2 family dwellings driveways is 18" for direct burial cable. I picked 18".
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Sounds right to me.
 
Pvc

Pvc

obviously a AHJ call but 356.12 (1) prohibits LFNC to be used where subject to physical damage, so if Sch 40 shouldn't be used, neither should LFNC, in my opinion.
 
augie47 said:
obviously a AHJ call but 356.12 (1) prohibits LFNC to be used where subject to physical damage, so if Sch 40 shouldn't be used, neither should LFNC, in my opinion.
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I am in complete agreement with your conclusion.
 
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