I have a Contractor who submitted American Ductile Iron pipe for direct bore under a river. The submittal said Water, Sewage pipe. Is there any other direct bore Conduit allowed besides HDPE ?? Yoopersup
I suppose he could use the water pipe as a sleeve and pull HDPE or some other appropriate wiring method through it. FPL did a directional bore under the river next to me but I didn't get to see what wiring method they used. I think the bore casing itself was that thick wall (1 1/4" or so) PVC pipe because there were pieces of it on the side of the road.
I've heard of the occasional AHJ insist that any 'sleeves' be UL listed/labeled as 'at least electrical material'. This came up on a resi multi family rental unit developement. The sparkies, and the cable & telco guys used scrap pieces of orange PVC leftovers from the sprinkler installers. The debate raged on for a few weeks & held the job up. Outcome was 'what was installed can remain, but do not use it anymore'.
As to your OP, I do not know of any other listed bore conduit other than HDPE.
If the installer calls it a "duct" I am not sure which article the AHJ could cite. "Ducts" are talked about in the derating articles but they are never defined. White PVC driveway sleeves are the norm here in new construction and I have never seen it cited as a violation.
I think there's some 'legal amnesia' taking place. What did we use before there was HDPE? After all, HDPE is pretty new to the code. Were we not doing direct bores before then?
Just because one product is listed for a specific use, that does not mean that only that product can be used.
As for re-tasking materials from their original use and applying them to electrical uses, that's a call for the AHJ to make. While the code says 'use one of these ...,' the code also recognizes that the AHJ can waive / approve / make exceptions; that's why he's called the "AHJ."
Make your case as to why the substitution is justified, and let him earn his pay.
Conduit (HDPE ) VS Pipe Taken from handbook of Poyethylene pipe. In general plastic pipes and plastic pipes are very similar in structure &composition , but deployment is where they differ. #1 Conduits do not have long term interial pressure. #2 Externial forces are unchecked if ovalized during installtion, may not recover during service. #3 Long term stress rupture is not a factor ( Hydrostatic design basis is not required in material selection. Because we used improper methods before now that we have them is there any reason not to install it correctly now??? #4 Conduit ID is chosen by cable occupancy,where internal clearences are critical.whereas for pipeing applactions ID is based on volumetic flow requirements. And theres tons more on why Proper Conduit should be installed.