Schedule 40 and 80 PVC 6" conduit connected in underground ductbank

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isupowerplant

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Ames, Iowa
I have an electrical contractor that connected schedule 40 and 80 PVC 6" conduit in an underground concrete encased ductbank. The issue was discovered when the mandrel would not go through the conduit. The contractor is stating that the installation is acceptable and meets the NEC. The owner wants them to replace the section of ductbank where the transition occurs due to the increased inside diameter of the schedule 80 PVC and potential for damaging cable during the pull. Does the code say anything about whether connecting schedule 40 and 80 PVC conduit is allowable? I could not find anything. Thanks
 
Why ??? Did the contractor run out of one type of conduit & substitute the other one ? Can the pull be done so that you go from the Schedule 80 (smallest dia) to schedule 40 (largest dia) ?
 
They installed and connected them by "accident". Pulling from the PVC 80 side into the 40 side could be possible, however there are two sets of conduit runs that this occurred in an 8 cell ductbank. One conduit will get 750 MCM cable pulled in the near future, the other will be left as spare for a future cable pull. The concern is that X years in the future, this situation will be forgotten about and cable will get pulled from the 40 into the 80 and damage the cable.
 
I do not see a code violation.

I am not a huge fan of the "someone might do something in the future" reasoning.

What do the contract plans and specifications state?
 
Here's what Carlon FAQ's say:

Q. Is there a problem in connecting schedule 40 and schedule 80 2" and 4" PVC conduits together in a run? Rigid steel sweeps are specified with schedule 80 PVC. The contractor mistakenly used schedule 40 under building slab. The contractor spoke to the owner and received permission to continue the conduit path with schedule 80.

A. No, schedule 40 and 80 can be connected with the use of couplings or their integral bell. The inside diameter of the spigot of the schedule 80 conduit should be reamed to allow a smooth transition from the 40 to the 80.
Click to expand...

http://www.carlonsales.com/schedule4080elbows.php
 
Well, it is a little late to ream the inside of the 80 at the transition. The Carlon document certainly recognizes that there is the potential for a real problem.
I suppose you could send a tapered reamer into the conduit on a flexible shaft if there are no bends in the way.
 
Specifications call out all schedule 40 to be installed in UG duct bank. Contractor is proposing to ream the edge of the installed conduit as suggested above. Thanks for the replies.
 
>>> off topic <<<
Just wanted to state that the above linked website it not Carlon, but an independent company that set up their own website with an URL that included the Carlon name.
>>> end off topic <<<


I was not able to find the above statement in current Carlon documentation. Based on a Google search, it appears to be from a PVC conduit manufacturer that was formelrly part of the company who once owned Carlon.


I'm not saying the statement is correct or not, it just does not appear to be our statement.
 
We had the conduit televised soon after the mandrel did not go through the conduit to determine the problem. They are proposing to televise it again if they attempt to ream the edge of the schedule 80 PVC.
 
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