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Discussion Starter #1
On a 200-amp service upgrade the other day, I had an inspector tell me that when passing under a residential driveway, PVC conduit is required, presumably by NEC, to be schedule 80. I've been unable to find a code reference. Does anyone know where that might be? THX
 

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I just had a job with sch 80 specified under a commercial driveway.
3” sch 80 is $20 more per 10’. Almost $60 per stick
 

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How deep was your PVC buried? if less than 18 inches, Sch. 80 would be required. See NEC 300.5
 

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Discussion Starter #8
In this case it was HDPE, directional boring, and at the driveway it was probably 36"
The inspector referenced the requirement for PVC, and said it might or would apply here also.
 

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It is really an inspectors call as to whether the install is subject to damage

(4) Enclosure or Raceway Damage. Where the enclosure or
raceway is subject to physical damage, the conductors shall be
installed in electrical metallic tubing, rigid metal conduit, intermediate
metal conduit, RTRC-XW, Schedule 80 PVC conduit,
or equivalent.
 

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The directional drilling guys usually pull in HDPE. Is that allowed?
 

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In this case, it was HDPE, directional boring, and at the driveway, it was probably 36"
The inspector referenced the requirement for PVC, and said it might or would apply here also.
At the end of the day the inspector, being the AHJ, has the final say unless you have a board or committee you can submit a review. However, based on the NEC this is what I find:

HDPE per NEC 353.6 says that the conduit is to be listed for the installation.

353.10(4) says that it can be direct burial in earth or concrete. The note refers to table 300.5

353.12(1) says it cannot be used "Where Exposed"

I would say that HDPE would fall under column 3 in table 300.5 since it is a Non-Metalic Raceway, but is must be "Listed" for direct burial. Under a driveway or parking lot, it has to be 24"

300.5(D)(4) "Enclosure or Raceway Damage - Where the enclosure or raceway is subject to physical damage, the conductors shall be installed in.....Schedule 80 PVC..."

My understanding would be this: HDPE would be allowed to be used underground as long as the type you're using is listed for that use. It would have to be at least 24" for under the driveway, however, you would have to transition to PVC before emerging from the ground. Whether the conductors are subject to damage is subjective, some people would say that everywhere is subject to damage.....

Ultimately you have to determine whether it is in your best interest to argue the inspector's requirements. Does the jurisdiction that the inspector works for have an adopted code that overrides the NEC? If not, Do you have a board or committee that you can present this to? Or would it be better to just comply???
 

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Don't most inspectors have a boss? Or similar
Obviously not every municipality, county or state has the same structure, but I would dare say that each jurisdiction has an ordinance that has a way to handle grievances and to discuss code application. The inspector has a boss, whether a director or city planer for example, but the inspector is usually given the authority over his jurisdiction and going to the boss is generally not the appropriate way to handle the dispute. Generally there is a way to have a public hearing to review the application of the code by the inspector. It usually has enough bureaucratic red tape to make it difficult for a quick resolution.
That’s the way it is in the states I work in. I can’t say for certain how things work in all places.
Some inspectors are reasonable to discuss code, especially if you’re knowledgeable. Others are dead set on their knowledge and there’s no discussion.
FYI - I was an electrical inspector in my area for 3 years. I had people try to go over my head to my boss. The local ordinance required a public hearing before the electrical board to settle those issues.
 

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Discussion Starter #14
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I would say that HDPE would fall under column 3 in table 300.5 since it is a Non-Metalic Raceway, but is must be "Listed" for direct burial. Under a driveway or parking lot, it has to be 24"
300.5(D)(4) "Enclosure or Raceway Damage - Where the enclosure or raceway is subject to physical damage, the conductors shall be installed in.....Schedule 80 PVC..."
My understanding would be this: HDPE would be allowed to be used underground as long as the type you're using is listed for that use.
I have done a number of such jobs last year or two, different jurisdictions. In every case, I pull in cable rated for direct burial. I've not yet had any inspector raise an issue. Just this one who mentioned something about 80 under driveways. Even he didn't seem too sure of himself.
 
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