underground ducts

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Re: underground ducts

I appreciate the comments. I want to clarify that I was not responsible for the situation, or that I would put in anything other than UL listed and labeled electrical conduit for the instalation. This pipe is in the ground and was available. I was asked if I thought it met NFPA. I think that 310-60.(a) is ment to allow abandoned pipe to be used for the installation of direct buried rated cable as long as the pipe is below the direct buried depth. If above that depth the cable must be installed in listed electrical conduit. I know that is a fine line, but so is conduit embedded in a concrete wall. Other considerations would be where the conduit exits the ground i.e. plenum areas etc.
 
Re: underground ducts

Don, I am wondering why you are using the NEC? Assuming this is a project for an electric utility, Rule 322 on page 195 of the NESC would apply. The concern is the ability of the duct to resist crushing (we use a lot of grade DB) and that the surface of the duct is free from sharp edges and burrs.

The whole of Section 32 is to be followed but Rule 322 is germane to this discussion. The only reason to go the NEC is if you are acting as a contractor for a private entity and are installing these facilities for sale to same.

We have used bituminous fiber ducts and sewer tile for ducts in the past. A lot of it is still in use. :D
 
Re: underground ducts

Originally posted by charlie:
Don, I am wondering why you are using the NEC? Assuming this is a project for an electric utility, Rule 322 on page 195 of the NESC would apply. The concern is the ability of the duct to resist crushing (we use a lot of grade DB) and that the surface of the duct is free from sharp edges and burrs.

The whole of Section 32 is to be followed but Rule 322 is germane to this discussion. The only reason to go the NEC is if you are acting as a contractor for a private entity and are installing these facilities for sale to same.

We have used bituminous fiber ducts and sewer tile for ducts in the past. A lot of it is still in use. :D
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I do not have a copy of NESC. The installation if for the city's economic development business park. The pipe was installed so the utility company could pull their cable through for ease of expansion. The contractor installed white water pipe for the utility to pull through. The utility company said that they can't use it because it isn't listed electrical conduit. The utility company told the city inspector to not allow the pipe to be used. Would this installation be allowed in the NESC?
 
Re: underground ducts

Sorry Don, you said you were a Utility Power Engineer and I thought you worked for an electric utility.

If the conduit is for the use of an electric utility, they have the right to specify where they are going to stick their cable. Where cable is installed for our use, we require only that the PVC conduit be gray. In this area, the sewer is green and SBC (telephone company) is white. We do not care what the material is as long as Rule 322 is followed. Other utilities have different views.

Would this installation be allowed in the NESC? Yes. Will this electric utility accept its use? No. In order to move forward with this job, the conduit will have to be replaced. You will have to deal directly with the electric utility to see if you can persuade them to move on this issue since it is their cable.

Good luck. :D
 
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