Thread: Underground raceway - Gas and Elec

Good morning,

Recently I came accross a2” PVC conduit being used as an underground raceway for UF (12-2 w/ ground) and soft copper piping (1/2")carrying natural gas. It’s open at both ends and comes through the wall in thebasement and turns up through the slab in a detached garage. Seeing as how the2” PVC isn’t required for the UF, I’m not sure that there is a code violationhere. Thoughts?

Thanks,
Jason

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I would not call this a raceway, the PVC is just a chase or sleeve and it's fine the way it is.

You can run the UF or a raceway through it along with water, cable, gas, etc. Think of it as a concrete tunnel underground, but on a small scale.

Originally Posted by Jason V. Advani

Recently I came accross a2” PVC conduit being used as an underground raceway for UF (12-2 w/ ground) and soft copper piping (1/2")carrying natural gas. It’s open at both ends and comes through the wall in thebasement and turns up through the slab in a detached garage. Seeing as how the2” PVC isn’t required for the UF, I’m not sure that there is a code violationhere. Thoughts?

Jason,

That is not allowed.

From the 2006 IRC:
- G2415.11 (404.11) Piping underground beneath buildings. Piping installed underground beneath buildings is prohibited except where the piping is encased in a conduit of wrought iron, plastic pipe, or steel pipe designed to withstand the superimposed loads. Such conduit shall extend into an occupiable portion of the building and, at the point where the conduit terminates in the building, the space between the conduit and the gas piping shall be sealed to prevent the possible entrance of any gas leakage. If the end sealing is capable of withstanding the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such conduit shall extend not less than 4 inches (102 mm) outside the building, shall be vented above grade to the outdoors, and shall be installed so as prevent the entrance of water and insects. The conduit shall be protected from corrosion in accordance with Section G2415.8.

Your description does not match the requirements. While not specifically prohibiting what you describe with the UF in that conduit with the gas line, trying to fulfill the requirements of the code seems to be impossible, or at the very least - impracticable, and as such would be prohibited unless each and every requirement was complied with.

Sounds like that section applies to piping "under buildings" where this is between buildings, at least the way I read it.

Originally Posted by Mike Kleisch

Sounds like that section applies to piping "under buildings" where this is between buildings, at least the way I read it.

Originally Posted by Jason V. Advani

and comes through the wall in the basement and turns up through the slab in a detached garage.

Mike,

I read that as being that it goes under at least some of the building(s).

Fair enough, but I think it would be fine as PVC is used underground and under buildings for sewer lines, and would withstand the loads. PVC was designed to be buried underground, don't remember a max depth, but I think this would satisfy the requirement...

Originally Posted by Mike Kleisch

Fair enough, but I think it would be fine as PVC is used underground and under buildings for sewer lines, and would withstand the loads. PVC was designed to be buried underground, don't remember a max depth, but I think this would satisfy the requirement...

Mike,

The code is referring to the loads of the gas pressure if there is a leak, not the loads of the soil above the piping.

Jerry,

I enjoy learning, especially other codes like the IRC, WI has its own code and I think in time will adapt those codes, but I see this going down the road of ask 12 inspectors a question and get 13 answers…

I still think this code section has been satisfied, as I read it:

You have a pipe, PVC, designed for underground burial or beneath buildings.

Where the section of gas pressure comes into play, is if the ends of the pipe are sealed and capable of withstanding the full pressure of the gas line, then the conduit, the PVC in this case, must be able to withstand that pressure as well.

I’m guessing this pipe just pops in on both ends and is stuffed with insulation, duct seal, or nothing at all, we don’t know, but needs to be sealed.

Maybe I’m missing something, and there are a couple unknowns, but I think it is good to go.

I agree that it is a sleeve and probably OK. However; I think, ( you will have to verify ), that the code requires a minimum separation distance between U/G gas and electrical conductors that is not being met inside a 2" conduit sleeve.

What code requires separation of underground gas and electrical? I don't believe there is one...

Originally Posted by Roland Miller

What code requires separation of underground gas and electrical? I don't believe there is one...

I admit I quickly scanned the NEC after my post and found nothing pro or con. It is a requirement in my Hood, but it may be utility driven. The concern is digging for one and damaging the other. Hence separation required. It makes sense to me, but I need help in discovering any associated codes.

I called the area Chief elec insp. on this. He said we require separation; one utility in each side of the ditch. I concurred that was my understanding; but said I could not find any code reference. He repeated they require it. I repeated my code reference question. He said there is none. So I would call this a NEC 90-4 ruling which is supposed to give some authority to the AHJ. I suppose I could take them to the matt on this and win because they have not received specific permission from the NEC and they have not printed it in local hand books. BTW another claimed reason for separation is to porovide for better heat dissipation and reduce inductance from utility to utility.

I know some utilities have requirements as well as some municipalities, but haven't been able to find it in any of the model codes. I agree it would be a good idea.

Thanks